Honda Cbr150

[thomo]

Not want to disrupt a good discussion, but the Honda CBR150R replacement will be on the Thai market in September. Nope its not a 150cc.

Well do continue... ya big tease.

[thaicbr]

<br>

<br>Whats the point in riding at higher RPM's if you have less power? Revving faster doesn't necessarily mean you have more power, the gains you claim to have were purely psychological. Louder doesn't mean faster.<br><br>Can you provide proof that the stock exhaust is too restrictive? its a two way road.<br><br>Regarding the NSR carb, I've installed these carbs on many different variations. From all stock, to 177cc stroked and cammed with 1mm extra lift, polished ports - and 118/35 always comes out on top for aggressive street driving, 120/35 or 118/38 if you insist on using an aftermarket pipe and don't want to blow the piston. However for stronger lowend move down to a 110-112 on a stock pipe and low end is much stronger but will shake when entering mid band, and if you ever cracked one of these bikes open you'd see that you can't fit larger valves, you can on the sonic though.<br><br>I have a stock head i just built up last night if you want a pic.<br><br>Here's a question, which one goes on first, the valve seal or the valve retainer?<br>

<br><br>So again you are evading questions. How do you know there is less power? YOU stated that the stock exhaust is better than an after market one. WHY is it better, I'm presuming that you haven't done any Dyno runs on any of the different variations you have built . Mate i have NEVER rebuilt a Cbr150 engine. However. I really do find it hard to believe that 118/35 is <u>optimum</u> for such a wide range of engine mods. I know the Sonic has a two valve head and the Cbr a 4 valve and most if not all engines have larger inlet valves than exhaust valves. I'm not deriding your skills i'm just asking how you can be so sure. And go against the general tuning rules that engineers the world over follow.<br><br> aseanmoto does a 170cc big bore kit including a reworked head with this spec. Bigger valves i believe.<br><div align="center">           <div align="center">Bore 66  x Stroke 49.2 mm. </div>         </div>                       <div align="center">-Valve IN 26 Valve EX 22<br><br><div align="left">"How is increasing the size of the exhaust going to allow more air to enter the combustion chamber?"<br><br>Well one way is that the exhaust gases are escaping quicker because of the larger bore so freeing up space for more (air pump).That may be why it revs quicker. Also did you know that the downpipe for the cbr150 is the same as the one for the euro cbr125.<br><br>Tony... Dyno run for 600b what a bargain! <br><br>Krs1.Tell ya what if you have a <u>stock</u> cbr150 available lets try it. I will pay for the 2 runs on the Dyno and supply the exhaust (an endurance unit). You supply the bike. Hows that sound? <br>In reality it would need a few more runs to get the jetting correct for optimum performance. But it should be ok straight from the box.<br></div></div><br>

I know there's less power because i just have to get on and ride it, all my friends have to do is get on and ride, and all my friends grandmother has to do is get on and ride it. Simple.

If that's not enough for you i have quarter miles times that can prove it. But then again you would have to be there and see it to believe it.So that's how i know, and i'm not evading anything.

You are however evading the question of how you know stock is restricted?

What tuning rules are you talking about that engineers follow the world over? If all rules were followed by every engineer in the world. it doesn't seem like there would ever be any type of advancement, and we'd never move forward. It is however the pioneering of certain individuals who break free from the norms and do whats not expected of them that DO advance humanity into the future.

I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best, for a simple reason and that's because you've never experimented, if you did you'd know first had what the results are.. I have an idea - try it, instead of just talking about it, you'll find that you don't need a dyno at all, it still perplexes me to this day why so many people are so quick to jump on the dyno bandwagon. When there are so many things that dyno correction factors just don't take into consideration. Simple

The downpipe for the CBR 150 and the CBR 125 are NOT the same they use the same outside casing and thats it, after the catalytic converter which is inside the downpipe, which contributes to back pressure, which this bike needs... there is an inner pipe, the inner pipe on the Thai CBR150 is 6 inches longer than a euro spec CBR 125. The Euro spec CBR 125's are actually sonic engines with slightly different magnetic flywheels and timing, the sonic engine GAINS from a bigger exhaust BUT the Thai CBR 150 does not. This is simply because there are two valves opposed to one and the rate of exhaust flow is much faster than the sonic. This is why you literally have to tame the CBR 150's exhaust by controlling the back pressure.

The exhaust gases that are being freed on the exhaust stroke is the same for both exhaust, as can be determined by TDC (top dead center) just at different rates, unless the aftermarket pipe magically extends the stroke on the exhaust stroke, the same amount of exhaust will be moved because its dictated by stroke length.

An imbalance to the other cycles however will be introduced, unless you compensate on the intake side. This imbalance is what causes you to have less power at higher RPM'S. Imagine a string of clay, you pull it slow it'll get quite a bit longer. BUT if you pull it too fast its going to rip almost immediately. By introducing a faster exhaust rate and not preparing the intake side the air string on intake isn't going to be as dense, this is why there's a loss of torque, unless you compensate.

Aseanmotos claim of bigger valves is bogus, you'd have to widen the valve seats as well as the ex/in ports, and when that happens you WILL have head gasket leaks, I can fit bigger valves on the CBR 150 no problem, I can go up about 2mm in size for each one.

But there's no point in doing it if you cant widen the valve seats. If you'd like gasket leaks every 1k Kilos, go right ahead and do it.

Here's an interesting piece of info for you, the stock valve seats are double bevels, while replacement valve seats are single bevels. What this means is that the shims will have to be almost twice the original height, because the valve will sit lower in the chamber. - another reason why stock is best.

to answer my previous question to you, the valve seal goes on first.

next question, how many screws hold on the top of the stock carburetor, and how many screws need to be removed in order to remove the needle?

I'm in Chiang Mai or else i'd gladly take you out for some quarter mile runs and maybe even a beer.

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

"some quarter mile runs"

I think that now i understand more. You are setting your bikes up for 1/4 mile drags ala Thai style. so you are not really bothered about ridability, were i'm talking about optimum fast street riding.

Thanks for the detailed answer above.

Edited July 21, 2010 by thaicbr

[thaicbr]

Thomo.. I'm up for testing the exhausts. Maybe early next month. I think it's going to have to be a saturday, can you do that. Cheers Allan

[songoku777]

DBS pipes.. helps improve the 'power' of the engine. It's also very noisy.

Yes very noisy! - i installed a DB killer on mine.. it's not as quiet as the stock, but not enough to wake up the dead. Also, shorter mufflers are generally more noisy.

I am about to buy a CBR150 (first bike) and read up on a number of things I should watch out for when buying a used bike (green book, engine/frame number...).

Since I might need to check the bike myself, can anyone tell me where on the CBR150 can I find the engine and frame numbers? (pictures would be appreciated )

In the same context - can someone recommend a mechanic (or anyone else who knows their stuff) who I could get for a fee and check the bike for me?

HTH ...

About the never ending argument on open pipe vs stock pipe.. based on my own experience.. the stock pipe is most ECONOMICAL, but a more open pipe (combined with other fine tuning elements) would be the most EFFICIENT. But whatever CBR mod (or stock config) one might have.. as long as they're happy with it (and serves the rider's purpose) ... thats ok

[songoku777]

What do you guys use for storage on short trips (e.g. magnetic bags on the tank, top bins, dry bags strapped on the back seat)? Do you find that's enough for a weekend trip to the beach?

I just have a dislike for riding with a backpack and am wondering what alternatives there are with the CBR150.

This bike belongs to a friend of mine who calls 500km rides a 'short trip' >,<

It's got all you need to travel anywhere and survive. 2 givi tour packs, 1 center givi box, a tank bag, and a water bottle ^^

A video of the bike's rear view on a group ride can be found here :

NOTE : The center givi is not attached to the bike in this video

[troehr]

What do you guys use for storage on short trips (e.g. magnetic bags on the tank, top bins, dry bags strapped on the back seat)? Do you find that's enough for a weekend trip to the beach?

I just have a dislike for riding with a backpack and am wondering what alternatives there are with the CBR150.

This bike belongs to a friend of mine who calls 500km rides a 'short trip' >,<

It's got all you need to travel anywhere and survive. 2 givi tour packs, 1 center givi box, a tank bag, and a water bottle ^^

A video of the bike's rear view on a group ride can be found here :

NOTE : The center givi is not attached to the bike in this video

Where did he buy the cases and the fittings? That is exactly the setup I have been looking for mine. But have not been able to find the side cases for a decent price.

T

[T_Dog]

Here's a pic of our last trip two months ago. 850 KM with just a day pack and two up. Photo taken on the way to Mae Chaem before we headed east to Khun Yuam and points north. You really don't need to carry much when cruising in Northern Thailand.

[BigBikeBKK]

Here's a pic of our last trip two months ago. 850 KM with just a day pack and two up. Photo taken on the way to Mae Chaem before we headed east to Khun Yuam and points north. You really don't need to carry much when cruising in Northern Thailand.

Nice!

We're heading up that way tomorrow- BKK-Tak-Mae Sot-Mae-Sariang on day one. Keeping our fingers crossed for decent weather. Happy Trails! Tony

[BigBikeBKK]

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

Well, it's a fact that Allan's got a bigger ass so I think I'll trust his ass dyno over CM racer boy's

[thaicbr]

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

Well, it's a fact that Allan's got a bigger ass so I think I'll trust his ass dyno over CM racer boy's

Thanks Tony IT's true.(about the big ass, BUT it aint as big as Rustic's)

[thomo]

Thomo.. I'm up for testing the exhausts. Maybe early next month. I think it's going to have to be a saturday, can you do that. Cheers Allan

Possibly, I usually work on Saturdays. But of course have the time off around the queens birthday. Think that Sat is the 15th.

[BigBikeBKK]

Thomo.. I'm up for testing the exhausts. Maybe early next month. I think it's going to have to be a saturday, can you do that. Cheers Allan

Possibly, I usually work on Saturdays. But of course have the time off around the queens birthday. Think that Sat is the 15th.

I rather expect the staff at Dirtshop will also have time off for the Queen's B-Day

Lemme know when you guys decide to go as I'd like to watch and perhaps test one of my bikes as well.

Ride On!

Tony

[thomo]

I rather expect the staff at Dirtshop will also have time off for the Queen's B-Day

That is true.

[KRS1]

<br>

<br>Whats the point in riding at higher RPM's if you have less power? Revving faster doesn't necessarily mean you have more power, the gains you claim to have were purely psychological. Louder doesn't mean faster.<br><br>Can you provide proof that the stock exhaust is too restrictive? its a two way road.<br><br>Regarding the NSR carb, I've installed these carbs on many different variations. From all stock, to 177cc stroked and cammed with 1mm extra lift, polished ports - and 118/35 always comes out on top for aggressive street driving, 120/35 or 118/38 if you insist on using an aftermarket pipe and don't want to blow the piston. However for stronger lowend move down to a 110-112 on a stock pipe and low end is much stronger but will shake when entering mid band, and if you ever cracked one of these bikes open you'd see that you can't fit larger valves, you can on the sonic though.<br><br>I have a stock head i just built up last night if you want a pic.<br><br>Here's a question, which one goes on first, the valve seal or the valve retainer?<br>

<br><br>So again you are evading questions. How do you know there is less power? YOU stated that the stock exhaust is better than an after market one. WHY is it better, I'm presuming that you haven't done any Dyno runs on any of the different variations you have built . Mate i have NEVER rebuilt a Cbr150 engine. However. I really do find it hard to believe that 118/35 is <u>optimum</u> for such a wide range of engine mods. I know the Sonic has a two valve head and the Cbr a 4 valve and most if not all engines have larger inlet valves than exhaust valves. I'm not deriding your skills i'm just asking how you can be so sure. And go against the general tuning rules that engineers the world over follow.<br><br> aseanmoto does a 170cc big bore kit including a reworked head with this spec. Bigger valves i believe.<br><div align="center">           <div align="center">Bore 66  x Stroke 49.2 mm. </div>         </div>                       <div align="center">-Valve IN 26 Valve EX 22<br><br><div align="left">"How is increasing the size of the exhaust going to allow more air to enter the combustion chamber?"<br><br>Well one way is that the exhaust gases are escaping quicker because of the larger bore so freeing up space for more (air pump).That may be why it revs quicker. Also did you know that the downpipe for the cbr150 is the same as the one for the euro cbr125.<br><br>Tony... Dyno run for 600b what a bargain! <br><br>Krs1.Tell ya what if you have a <u>stock</u> cbr150 available lets try it. I will pay for the 2 runs on the Dyno and supply the exhaust (an endurance unit). You supply the bike. Hows that sound? <br>In reality it would need a few more runs to get the jetting correct for optimum performance. But it should be ok straight from the box.<br></div></div><br>

I know there's less power because i just have to get on and ride it, all my friends have to do is get on and ride, and all my friends grandmother has to do is get on and ride it. Simple.

If that's not enough for you i have quarter miles times that can prove it. But then again you would have to be there and see it to believe it.So that's how i know, and i'm not evading anything.

You are however evading the question of how you know stock is restricted?

What tuning rules are you talking about that engineers follow the world over? If all rules were followed by every engineer in the world. it doesn't seem like there would ever be any type of advancement, and we'd never move forward. It is however the pioneering of certain individuals who break free from the norms and do whats not expected of them that DO advance humanity into the future.

I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best, for a simple reason and that's because you've never experimented, if you did you'd know first had what the results are.. I have an idea - try it, instead of just talking about it, you'll find that you don't need a dyno at all, it still perplexes me to this day why so many people are so quick to jump on the dyno bandwagon. When there are so many things that dyno correction factors just don't take into consideration. Simple

The downpipe for the CBR 150 and the CBR 125 are NOT the same they use the same outside casing and thats it, after the catalytic converter which is inside the downpipe, which contributes to back pressure, which this bike needs... there is an inner pipe, the inner pipe on the Thai CBR150 is 6 inches longer than a euro spec CBR 125. The Euro spec CBR 125's are actually sonic engines with slightly different magnetic flywheels and timing, the sonic engine GAINS from a bigger exhaust BUT the Thai CBR 150 does not. This is simply because there are two valves opposed to one and the rate of exhaust flow is much faster than the sonic. This is why you literally have to tame the CBR 150's exhaust by controlling the back pressure.

The exhaust gases that are being freed on the exhaust stroke is the same for both exhaust, as can be determined by TDC (top dead center) just at different rates, unless the aftermarket pipe magically extends the stroke on the exhaust stroke, the same amount of exhaust will be moved because its dictated by stroke length.

An imbalance to the other cycles however will be introduced, unless you compensate on the intake side. This imbalance is what causes you to have less power at higher RPM'S. Imagine a string of clay, you pull it slow it'll get quite a bit longer. BUT if you pull it too fast its going to rip almost immediately. By introducing a faster exhaust rate and not preparing the intake side the air string on intake isn't going to be as dense, this is why there's a loss of torque, unless you compensate.

Aseanmotos claim of bigger valves is bogus, you'd have to widen the valve seats as well as the ex/in ports, and when that happens you WILL have head gasket leaks, I can fit bigger valves on the CBR 150 no problem, I can go up about 2mm in size for each one.

But there's no point in doing it if you cant widen the valve seats. If you'd like gasket leaks every 1k Kilos, go right ahead and do it.

Here's an interesting piece of info for you, the stock valve seats are double bevels, while replacement valve seats are single bevels. What this means is that the shims will have to be almost twice the original height, because the valve will sit lower in the chamber. - another reason why stock is best.

to answer my previous question to you, the valve seal goes on first.

next question, how many screws hold on the top of the stock carburetor, and how many screws need to be removed in order to remove the needle?

I'm in Chiang Mai or else i'd gladly take you out for some quarter mile runs and maybe even a beer.

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

"some quarter mile runs"

I think that now i understand more. You are setting your bikes up for 1/4 mile drags ala Thai style. so you are not really bothered about ridability, were i'm talking about optimum fast street riding.

Thanks for the detailed answer above.

Your suggesting a dyno is more real life than a quarter mile run? Wake up please.

I found it hard to believe also that 118/35 worked best, but keep in mind the NSR carb flows much better than the stock carb. So its getting much more fuel than the stock carb.

You don't need a dyno to see the differences in jets, unless your a total newb, go above a 125 jet and the only thing the bike likes to do is bog out, you don't need a dyno to feel that. You also don't need a dyno to feel the bike shake when its transitioning from low to mid and running too lean. When transitioning from mid to hi, you can tell when the motors happy or if its sluggish. All these replies just indicate that you don't have much experience at all and have simply fallen into the trap that bigger MUST be better, no disrespect intended, but when you actually do it, you can just tell.

in other words some may need a dyno - But i don't

I didn't give this explanation earlier because its a lot of typing, and I knew that this type of analysis requires high levels of spacial (not special) visualization, that most people just can't grasp. The average person cannot even draw a 2d picture in their mind.

To answer the previous question, the stock carb has two screws up top, and no other screws within the carb need to be removed to remove the needle, it slides right out.

[KRS1]

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

Well, it's a fact that Allan's got a bigger ass so I think I'll trust his ass dyno over CM racer boy's

Is that your shop across the way from Loi Kroh? It says Tony's big bike, so it must be yours ehh?

[KRS1]

<br>

<br>Whats the point in riding at higher RPM's if you have less power? Revving faster doesn't necessarily mean you have more power, the gains you claim to have were purely psychological. Louder doesn't mean faster.<br><br>Can you provide proof that the stock exhaust is too restrictive? its a two way road.<br><br>Regarding the NSR carb, I've installed these carbs on many different variations. From all stock, to 177cc stroked and cammed with 1mm extra lift, polished ports - and 118/35 always comes out on top for aggressive street driving, 120/35 or 118/38 if you insist on using an aftermarket pipe and don't want to blow the piston. However for stronger lowend move down to a 110-112 on a stock pipe and low end is much stronger but will shake when entering mid band, and if you ever cracked one of these bikes open you'd see that you can't fit larger valves, you can on the sonic though.<br><br>I have a stock head i just built up last night if you want a pic.<br><br>Here's a question, which one goes on first, the valve seal or the valve retainer?<br>

<br><br>So again you are evading questions. How do you know there is less power? YOU stated that the stock exhaust is better than an after market one. WHY is it better, I'm presuming that you haven't done any Dyno runs on any of the different variations you have built . Mate i have NEVER rebuilt a Cbr150 engine. However. I really do find it hard to believe that 118/35 is <u>optimum</u> for such a wide range of engine mods. I know the Sonic has a two valve head and the Cbr a 4 valve and most if not all engines have larger inlet valves than exhaust valves. I'm not deriding your skills i'm just asking how you can be so sure. And go against the general tuning rules that engineers the world over follow.<br><br> aseanmoto does a 170cc big bore kit including a reworked head with this spec. Bigger valves i believe.<br><div align="center">           <div align="center">Bore 66  x Stroke 49.2 mm. </div>         </div>                       <div align="center">-Valve IN 26 Valve EX 22<br><br><div align="left">"How is increasing the size of the exhaust going to allow more air to enter the combustion chamber?"<br><br>Well one way is that the exhaust gases are escaping quicker because of the larger bore so freeing up space for more (air pump).That may be why it revs quicker. Also did you know that the downpipe for the cbr150 is the same as the one for the euro cbr125.<br><br>Tony... Dyno run for 600b what a bargain! <br><br>Krs1.Tell ya what if you have a <u>stock</u> cbr150 available lets try it. I will pay for the 2 runs on the Dyno and supply the exhaust (an endurance unit). You supply the bike. Hows that sound? <br>In reality it would need a few more runs to get the jetting correct for optimum performance. But it should be ok straight from the box.<br></div></div><br>

I know there's less power because i just have to get on and ride it, all my friends have to do is get on and ride, and all my friends grandmother has to do is get on and ride it. Simple.

If that's not enough for you i have quarter miles times that can prove it. But then again you would have to be there and see it to believe it.So that's how i know, and i'm not evading anything.

You are however evading the question of how you know stock is restricted?

What tuning rules are you talking about that engineers follow the world over? If all rules were followed by every engineer in the world. it doesn't seem like there would ever be any type of advancement, and we'd never move forward. It is however the pioneering of certain individuals who break free from the norms and do whats not expected of them that DO advance humanity into the future.

I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best, for a simple reason and that's because you've never experimented, if you did you'd know first had what the results are.. I have an idea - try it, instead of just talking about it, you'll find that you don't need a dyno at all, it still perplexes me to this day why so many people are so quick to jump on the dyno bandwagon. When there are so many things that dyno correction factors just don't take into consideration. Simple

The downpipe for the CBR 150 and the CBR 125 are NOT the same they use the same outside casing and thats it, after the catalytic converter which is inside the downpipe, which contributes to back pressure, which this bike needs... there is an inner pipe, the inner pipe on the Thai CBR150 is 6 inches longer than a euro spec CBR 125. The Euro spec CBR 125's are actually sonic engines with slightly different magnetic flywheels and timing, the sonic engine GAINS from a bigger exhaust BUT the Thai CBR 150 does not. This is simply because there are two valves opposed to one and the rate of exhaust flow is much faster than the sonic. This is why you literally have to tame the CBR 150's exhaust by controlling the back pressure.

The exhaust gases that are being freed on the exhaust stroke is the same for both exhaust, as can be determined by TDC (top dead center) just at different rates, unless the aftermarket pipe magically extends the stroke on the exhaust stroke, the same amount of exhaust will be moved because its dictated by stroke length.

An imbalance to the other cycles however will be introduced, unless you compensate on the intake side. This imbalance is what causes you to have less power at higher RPM'S. Imagine a string of clay, you pull it slow it'll get quite a bit longer. BUT if you pull it too fast its going to rip almost immediately. By introducing a faster exhaust rate and not preparing the intake side the air string on intake isn't going to be as dense, this is why there's a loss of torque, unless you compensate.

Aseanmotos claim of bigger valves is bogus, you'd have to widen the valve seats as well as the ex/in ports, and when that happens you WILL have head gasket leaks, I can fit bigger valves on the CBR 150 no problem, I can go up about 2mm in size for each one.

But there's no point in doing it if you cant widen the valve seats. If you'd like gasket leaks every 1k Kilos, go right ahead and do it.

Here's an interesting piece of info for you, the stock valve seats are double bevels, while replacement valve seats are single bevels. What this means is that the shims will have to be almost twice the original height, because the valve will sit lower in the chamber. - another reason why stock is best.

to answer my previous question to you, the valve seal goes on first.

next question, how many screws hold on the top of the stock carburetor, and how many screws need to be removed in order to remove the needle?

I'm in Chiang Mai or else i'd gladly take you out for some quarter mile runs and maybe even a beer.

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

"some quarter mile runs"

I think that now i understand more. You are setting your bikes up for 1/4 mile drags ala Thai style. so you are not really bothered about ridability, were i'm talking about optimum fast street riding.

Thanks for the detailed answer above.

Why do you assume it has to be a drag? Quarter mile times don't have to be drag times. When we time the bikes we start off at 800 RPM. How else would you evaluate transition of power? If i wasn't bothered by rideability why would i be recommending the stock pipe? Please think before you speak.

True we've done some drag type runs and timed them, but who wouldn't?

[thaicbr]

kRS1 "You don't need a dyno to see the differences in jets, unless your a total newb, go above a 125 jet and the only thing the bike likes to do is bog out, you don't need a dyno to feel that. You also don't need a dyno to feel the bike shake when its transitioning from low to mid and running too lean. When transitioning from mid to hi, you can tell when the motors happy or if its sluggish."

I thought that Mid range on a carb is controlled by the needle and that raising the needle would sort out the lean spot in the mid-range. But again being a noob i have probably got that wrong :D

[BigBikeBKK]

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

Well, it's a fact that Allan's got a bigger ass so I think I'll trust his ass dyno over CM racer boy's

Is that your shop across the way from Loi Kroh? It says Tony's big bike, so it must be yours ehh?

Urm, yeah, cuz I'm the only guy in Thailand named Tony, right?

[troehr]

So what does a NSR carb cost? Is there anything special that you need to do? Is this something the local Honda shop is capable of doing correctly?

[KRS1]

kRS1 "You don't need a dyno to see the differences in jets, unless your a total newb, go above a 125 jet and the only thing the bike likes to do is bog out, you don't need a dyno to feel that. You also don't need a dyno to feel the bike shake when its transitioning from low to mid and running too lean. When transitioning from mid to hi, you can tell when the motors happy or if its sluggish."

I thought that Mid range on a carb is controlled by the needle and that raising the needle would sort out the lean spot in the mid-range. But again being a noob i have probably got that wrong :D

God you really are a moron, when did i ever say the needle didn't need adjustment, actually in most cases all you'd have to do is turn the mixture screw.But i guess you knew that since you didn't mention it.

Stop making things up, and answer the question of how you can prove the stock exhaust is too small.

Well, you done made me look up your old CBR post and it appears you sold your old bike with a carb that needed tuning as well as running a back sprocket that was much too small even for a 30 lb midget.

Why don't you tell us why you sold the bike with an improperly tuned carb and sprockets that couldn't beat a turtle? did you raise the needle on that bike too? Why didn't you just tune it properly before you sold it? Oh that's right you've never taken apart the carb, so who did it?:jap:

[KRS1]

Krs1. Your full of questions you know i can't answer because as i told you i have never dimantled a Cbr150. Why did you not give this explaination a few posts back when asked. One thing i find funny, you told us all that what we are feeling is bogus (seat of the pants dyno) but claim that YOUR seat of the pants dyno is valid and then stating that a Dyno is no good.

as for this "I know you'd find it hard to believe 118/35 is best, just like you find it hard to believe that the stock exhaust is best"

I do find it hard to believe that a setting of 118/35 on the nsrcarb is optimum for a Cbr 150 stock bike AND a bigebore,cammed bike.

BUT then thats your 'seat of the pants dyno' figuring that out. So it must be right.

Hey you may be right but the few Cbr's i ridden have ALL felt more responsive when they have had a larger bore downpipe.

Well, it's a fact that Allan's got a bigger ass so I think I'll trust his ass dyno over CM racer boy's

Is that your shop across the way from Loi Kroh? It says Tony's big bike, so it must be yours ehh?

Urm, yeah, cuz I'm the only guy in Thailand named Tony, right?

So then where's your shop, you know, the place you make carbon fiber and try to push here on the forum. The warehouse, where's the warehouse? C'mon, your the man, your cool and quick witted and you have a 'BigBike', can we all just have a chance to be as cool as you?

Please?

[KRS1]

So what does a NSR carb cost? Is there anything special that you need to do? Is this something the local Honda shop is capable of doing correctly?

2000-2500 baht for an original 1500 baht for a fake. Need to rejet and use an NSR throttle cable, actual carb slips right in.Dealers don't usually take this project on, but you may get lucky.

[T_Dog]

Here's a pic of our last trip two months ago. 850 KM with just a day pack and two up. Photo taken on the way to Mae Chaem before we headed east to Khun Yuam and points north. You really don't need to carry much when cruising in Northern Thailand.

Nice!

We're heading up that way tomorrow- BKK-Tak-Mae Sot-Mae-Sariang on day one. Keeping our fingers crossed for decent weather. Happy Trails! Tony

Tony.... Wish we could join you! Last year we took a trip this time of year to Mae Sariang from CM and we both almost got hypothermia about 30 km from our guest house. Luckily a noodle shop, some hot tea, and a short wait for the rains to let up and we were good to go again. Amazing how cold it gets on some of those passes. You will definitely hit some rain up there this time of year, but it should be scenic and green. Have fun!

[thomo]

*enters poo fight momentarily*

Stop making things up, and answer the question of how you can prove the stock exhaust is too small.

Again, just to bring up, I don't think anybody is saying it is too small. Just that the much lighter, bigger aftermarkets give a better performance. Some agree, some don't.

*exits poo fight, with hopefully poo free clothes*

[dave_boo]

a ) So how do you know the stock exhaust is restrictive?

b ) Can you prove that its not already at the maximum size for best stock performance?

To create power you need more air coming in, not just out.

c ) How is increasing the size of the exhaust going to allow more air to enter the combustion chamber?

All these aftermarket exhaust in Thailand do are allow the bike to rev up faster, but you aren't seeing any gains in power or speed unless you make additional modifications. d) Your simply making less power at higher RPM's.

e ) Did you realize the exhaust valves in the cbr 150 are smaller than the intake valves? Honda must have done this for a reason or else they would have made them bigger if they wanted the exhaust to flow faster.

You want more power, buy a bigger carburetor like the NSR 28mm Keihin and jet it to 118/35. This carb can be bored out to a maximum of 31-32mm, you want more air this is it.

...and keep the original exhaust, because you aren't anywhere near the maximum velocity.

I'm sorry that I haven't been checking my emails recently and fell off this thread. However I just had to reply to this post since there's some things I'd like to address that I hadn't seen contested in following replies. I also took the liberty of coding my answers to the OP's reply.

a ) The stock exhaust is restrictive because Honda has to meet certain emissions standards. Hence the 'lean' tune and catalytic convertor.

b ) Of course for stock it's likely at relatively best performance; but if losing some weight and gaining a bit of power comes from an affordable upgrade, why not?

c ) Because it allows the expanding gas to exit even more easily from the combustion chamber, increasing the flow of fuel mixture since you are not running up against the wall of hot gasses that are exiting (I'll cover this a bit more later).

d ) How do you figure you'll make less power at higher levels? While at lower RPM levels back pressure helps a small displacement engine evacuate the chamber it is a liability at higher engine speeds thus the valves in the exhaust on certain bikes....plus who wouldn't want to get in the powerband more quickly? Grandma?

e ) The wrongness of that statement astounds me. ALL engines I've ever seen (perhaps 2T have same-same or larger ports; Thanh would have to state) have had smaller exhaust valves than intake. There's a stupidly simple explaination. Volumetric efficiency versus inertia. On a four stroke engine there are two ups and two downs for every power pulse in a cylinder. Let's consider that at STP (standard pressure and temperature--sea level at 70 something farenheit) an engine has to suck air in through an airbox, an air filtre, a series of tubes, a carb and occasionally a manifold. This air is some 14.5 PSI. All the suction of the piston traveling downwards on the intake stroke is used to transfer the air/fuel mixture through that restricitve path that I just mentioned and into the cylinder. A bit after BDC (bottom dead centre) the intake valves slap shut and the piston continues upwards to compress the mixture. Slightly before TDC (top dead centre) the spark plug should initiate the spark. As the flame edge spreads across the surface of the piston it reaches TDC and continues downward aided by the reaction (explosion). Somewhere before BDC the exhaust valve opens and starts allowing the spent gasses to escape. The valves stay open all the way past TDC which allows the escaping spent gasses to assist in the suction of the incoming cooler air charge which actually starts before TDC. Since the spent gasses are now extremely hot and are under increasing pressure during the upward tick of the exhaust stroke they are much easier to displace than those cooler ones you're trying to bring in. Since the spent gasses are more efficiently removed the valves can be smaller to allow more area in the head for the intake valves which have the 'harder' job. Your assertion that Honda would have made the valves bigger is incorrect.

[songoku777]

Where did he buy the cases and the fittings? That is exactly the setup I have been looking for mine. But have not been able to find the side cases for a decent price.

T

It's from a local shop where i come from. Look for Ryan.. i think he's the owner. Im sure they might have shipping arrangements if you like the price of the stuff

These links might help...

http://www.motorcyclephilippines.com/forums/forumdisplay.php?f=236

http://www.motoworld.com.ph/product_categories.php?cat=GIVI%20Cases

[T_Dog]

*enters poo fight momentarily*

Stop making things up, and answer the question of how you can prove the stock exhaust is too small.

Again, just to bring up, I don't think anybody is saying it is too small. Just that the much lighter, bigger aftermarkets give a better performance. Some agree, some don't.

*exits poo fight, with hopefully poo free clothes*

Hey, you hit on a factor that makes a lot of sense! The stock pipe is very heavy compared to my achy-breaky-Faddy. Getting rid of several pounds always makes a bike faster! I'll weigh them in a few days when I put my welded-yet-again over size pipe back on the bike.

[thaicbr]

"God you really are a moron, when did i ever say the needle didn't need adjustment, actually in most cases all you'd have to do is turn the mixture screw."

Exactly WHEN DID you ever talk about the needle until i mentioned it.

KRS1.... This Discussion..... which as far as i'm concerned is all it is. Started when i asked you what proof you had to your firm conviction that the original exhaust is better than ANY after market pipe. I don't believe that at any time i used rude or condesending words to you. So the statement that i'm a moron is a bit steep.

As for my old bike yes i did try and rejet it but due to my lack of Thai and getting the correct parts i left it as standard in the end. As for the gearing I honestly can't remember what they were when i sold it (stock i believe). I did enjoy experimenting with the bike but lack of time and the neccersary parts made it difficult.

You enjoy your bikes and tuning. I can tell, But sometimes other peoples ideas are valid as well.

I'm finished with this thread until after we Dyno Thomo's bike early next month. Have a nice long weekend everyone.

Edited July 22, 2010 by thaicbr

[KRS1]

a ) So how do you know the stock exhaust is restrictive?

b ) Can you prove that its not already at the maximum size for best stock performance?

To create power you need more air coming in, not just out.

c ) How is increasing the size of the exhaust going to allow more air to enter the combustion chamber?

All these aftermarket exhaust in Thailand do are allow the bike to rev up faster, but you aren't seeing any gains in power or speed unless you make additional modifications. d) Your simply making less power at higher RPM's.

e ) Did you realize the exhaust valves in the cbr 150 are smaller than the intake valves? Honda must have done this for a reason or else they would have made them bigger if they wanted the exhaust to flow faster.

You want more power, buy a bigger carburetor like the NSR 28mm Keihin and jet it to 118/35. This carb can be bored out to a maximum of 31-32mm, you want more air this is it.

...and keep the original exhaust, because you aren't anywhere near the maximum velocity.

I'm sorry that I haven't been checking my emails recently and fell off this thread. However I just had to reply to this post since there's some things I'd like to address that I hadn't seen contested in following replies. I also took the liberty of coding my answers to the OP's reply.

a ) The stock exhaust is restrictive because Honda has to meet certain emissions standards. Hence the 'lean' tune and catalytic convertor.

b ) Of course for stock it's likely at relatively best performance; but if losing some weight and gaining a bit of power comes from an affordable upgrade, why not?

c ) Because it allows the expanding gas to exit even more easily from the combustion chamber, increasing the flow of fuel mixture since you are not running up against the wall of hot gasses that are exiting (I'll cover this a bit more later).

d ) How do you figure you'll make less power at higher levels? While at lower RPM levels back pressure helps a small displacement engine evacuate the chamber it is a liability at higher engine speeds thus the valves in the exhaust on certain bikes....plus who wouldn't want to get in the powerband more quickly? Grandma?

e ) The wrongness of that statement astounds me. ALL engines I've ever seen (perhaps 2T have same-same or larger ports; Thanh would have to state) have had smaller exhaust valves than intake. There's a stupidly simple explaination. Volumetric efficiency versus inertia. On a four stroke engine there are two ups and two downs for every power pulse in a cylinder. Let's consider that at STP (standard pressure and temperature--sea level at 70 something farenheit) an engine has to suck air in through an airbox, an air filtre, a series of tubes, a carb and occasionally a manifold. This air is some 14.5 PSI. All the suction of the piston traveling downwards on the intake stroke is used to transfer the air/fuel mixture through that restricitve path that I just mentioned and into the cylinder. A bit after BDC (bottom dead centre) the intake valves slap shut and the piston continues upwards to compress the mixture. Slightly before TDC (top dead centre) the spark plug should initiate the spark. As the flame edge spreads across the surface of the piston it reaches TDC and continues downward aided by the reaction (explosion). Somewhere before BDC the exhaust valve opens and starts allowing the spent gasses to escape. The valves stay open all the way past TDC which allows the escaping spent gasses to assist in the suction of the incoming cooler air charge which actually starts before TDC. Since the spent gasses are now extremely hot and are under increasing pressure during the upward tick of the exhaust stroke they are much easier to displace than those cooler ones you're trying to bring in. Since the spent gasses are more efficiently removed the valves can be smaller to allow more area in the head for the intake valves which have the 'harder' job. Your assertion that Honda would have made the valves bigger is incorrect.

a) The cbr 150 utilizes a exhaust gas recirculation valve, the bike is not lean tuned -its correctly tuned, and the catalyst isn't there solely for the purpose of meeting emissions, its for the back pressure that's needed, the tube that extends past the Cat is also there to increase velocity. If you want to gain some low end in exchange for hi end, plug the exhaust gas recirculation valve.

Lighter doesn't always mean better performance, thats why a crank is designed the way it is - i had a nissan bluebird SSS that was faster stock with 2 people than 1.

c) The exhaust gases are directly related to the design of the intake, your not increasing the volume of fuel/air intake unless you modify the intake. You may increase the rate, but not volume, more than likely the volume has been reduced without first accommodating the intake side. I already wrote that, you missed it.

d) Back pressure is an important factor at all levels not just low levels, as a matter of fact it's really important at high speeds or else you'll just be making a lot of noise and not going anywhere. Why would you want to enter the powerband with less power at higher rpm's? Why? Do you enjoy wasting fuel?

e) Thank you for that long winded post and for shooting yourself in the foot, to sum things up - you'd have to adjust valve overlap to accomodate a commercially available aftermarket pipe. - another reason why stock is best.

I suggest you study muffler design, then come to a conclusion of just what the chambers in the silencer is designed for, its not just to attenuate the sound.

Thank you have a nice day - I'm out

[KRS1]

"God you really are a moron, when did i ever say the needle didn't need adjustment, actually in most cases all you'd have to do is turn the mixture screw."

Exactly WHEN DID you ever talk about the needle until i mentioned it.

KRS1.... This Discussion..... which as far as i'm concerned is all it is. Started when i asked you what proof you had to your firm conviction that the original exhaust is better than ANY after market pipe. I don't believe that at any time i used rude or condesending words to you. So the statement that i'm a moron is a bit steep.

As for my old bike yes i did try and rejet it but due to my lack of Thai and getting the correct parts i left it as standard in the end. As for the gearing I honestly can't remember what they were when i sold it (stock i believe). I did enjoy experimenting with the bike but lack of time and the neccersary parts made it difficult.

You enjoy your bikes and tuning. I can tell, But sometimes other peoples ideas are valid as well.

I'm finished with this thread until after we Dyno Thomo's bike early next month. Have a nice long weekend everyone.

Doesn't seem like you mentioned the mixture screw either, why didn't you mention the mixture screw before? - did it slip your mind?

But you've never taken apart your carb, so how did you try to tune it yourself? Seems like any normal person would just take the part in hand to the parts guy and just show him what you needed.

Your sprockets weren't stock, they were something way off the mark like 34 or 36 rear. I can see why you'd think that endurance is better now, you'd need it to rev just to keep from stalling.