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Posted

Moving the mass upwards will shift the CofG upwards, not forwards.

I guess pillions are not very good for bikes in terms of balance, luggage too and there are very few places on the front of most bikes to mount stuff, apart from a tank bag, although I have seen some tool tubes, on expedition bikes.

Ever hear of weight transfer? Below is the formula.

ΔWeightfront = ah/wm

ΔWeightfront is obviously the change (delta) of weight on the front tyre, a is longitudinal acceleration, h is centre of mass height, w is wheelbase and m is total mass. Let's plug in some values.

A, w, and m we'll keep the same as we're going to simply change the mass height. Let's say we increase it 2 cm. Note that I took 1/2 of the CBR250's height and the rest of the measurements from that bike.

stock.......................1*563/1370*166

raise preload 2cm...1*565/1370*166

Means you have 68.22 stock and 68.46 raising the preload. You start adding mass (to the 166) and the delta is going to increase even further.

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Posted

It's all good with the Honda dealer now .... What I would like to know it's possible for full system after market pipe ( TwoBrothers ) damaging that engine like that ?

Many variables.

If the aftermarket pipe made the engine breath better - exhaust gases could exit quicker - this may lean out the mixture.

Most OEM ECU's will compensate for changes - but to what degree I do not know.

If the mixture is made more lean - piston crown temperatures will rise, along with exhaust valves especially.

Lean is not good - the factories do it to pass fuel economy targets, not to enhance performance.

Most aftermarket ECU 'Reflash' is to add fuel to lean spots in the rev band.

Too lean = too hot. Too hot = burned valves and melted pistons.

That being said your bike is probably OK

What did the pipe manufacturer recommend ? Reflash, airbox mods, maybe a Power Commander (I have never had much luck with them but some have)

???

for me all that look a like !!!!!!!

after they repair everything where should I go get that done ?

Posted
???

for me all that look a like !!!!!!!

after they repair everything where should I go get that done ?

First one would like to know, what was broken ?

Then, if you don't understand all that mechanical stuff, why you modify the bike ? Unhappy with performances? Did you found an improvement? Want it louder?

Posted

Moving the mass upwards will shift the CofG upwards, not forwards.

I guess pillions are not very good for bikes in terms of balance, luggage too and there are very few places on the front of most bikes to mount stuff, apart from a tank bag, although I have seen some tool tubes, on expedition bikes.

Ever hear of weight transfer? Below is the formula.

ΔWeightfront = ah/wm

ΔWeightfront is obviously the change (delta) of weight on the front tyre, a is longitudinal acceleration, h is centre of mass height, w is wheelbase and m is total mass. Let's plug in some values.

A, w, and m we'll keep the same as we're going to simply change the mass height. Let's say we increase it 2 cm. Note that I took 1/2 of the CBR250's height and the rest of the measurements from that bike.

stock.......................1*563/1370*166

raise preload 2cm...1*565/1370*166

Means you have 68.22 stock and 68.46 raising the preload. You start adding mass (to the 166) and the delta is going to increase even further.

Sorry mate this is nonsense.

You cannot use this formula, since it is based on acceleration, we are talking about all conditions positive, zero and negative acceleration. That means that your "mass transfer" will be moving all the time you are riding the bike, this formula is designed predominately for braking distance calculations. The reason 4x4's have such long braking distance is because the Cof G is so high, so raising any part of the bike is not a good idea anyway.

If you doubt this put all of the values in your formula, rather than just some and then re-post the result.

Posted

Moving the mass upwards will shift the CofG upwards, not forwards.

I guess pillions are not very good for bikes in terms of balance, luggage too and there are very few places on the front of most bikes to mount stuff, apart from a tank bag, although I have seen some tool tubes, on expedition bikes.

Ever hear of weight transfer? Below is the formula.

ΔWeightfront = ah/wm

ΔWeightfront is obviously the change (delta) of weight on the front tyre, a is longitudinal acceleration, h is centre of mass height, w is wheelbase and m is total mass. Let's plug in some values.

A, w, and m we'll keep the same as we're going to simply change the mass height. Let's say we increase it 2 cm. Note that I took 1/2 of the CBR250's height and the rest of the measurements from that bike.

stock.......................1*563/1370*166

raise preload 2cm...1*565/1370*166

Means you have 68.22 stock and 68.46 raising the preload. You start adding mass (to the 166) and the delta is going to increase even further.

Sorry mate this is nonsense.

You cannot use this formula, since it is based on acceleration, we are talking about all conditions positive, zero and negative acceleration. That means that your "mass transfer" will be moving all the time you are riding the bike, this formula is designed predominately for braking distance calculations. The reason 4x4's have such long braking distance is because the Cof G is so high, so raising any part of the bike is not a good idea anyway.

If you doubt this put all of the values in your formula, rather than just some and then re-post the result.

If you didn't know that mass transfer happens in all sorts of directions during riding...wow, I can't believe that you're criticising my post (as an aside, using negative acceleration means you are raising a negative number...and -x*-x = x*x; i.e. the difference is greater than 'positive acceleration').

Even at rest there's acceleration. 9.8 m/s2.

I'd rather not drag this thread down with bickering, and since it's obvious that the physics are a subject that most lay people have problems with, I propose a practical experiment. Take a decently weighted length of whatever. Rest one end on a scale and hold the other end level with the scale. Start raising the end you are holding. See how much more weight ends up registering on the scale.

Posted

Moving the mass upwards will shift the CofG upwards, not forwards.

I guess pillions are not very good for bikes in terms of balance, luggage too and there are very few places on the front of most bikes to mount stuff, apart from a tank bag, although I have seen some tool tubes, on expedition bikes.

Ever hear of weight transfer? Below is the formula.

ΔWeightfront = ah/wm

ΔWeightfront is obviously the change (delta) of weight on the front tyre, a is longitudinal acceleration, h is centre of mass height, w is wheelbase and m is total mass. Let's plug in some values.

A, w, and m we'll keep the same as we're going to simply change the mass height. Let's say we increase it 2 cm. Note that I took 1/2 of the CBR250's height and the rest of the measurements from that bike.

stock.......................1*563/1370*166

raise preload 2cm...1*565/1370*166

Means you have 68.22 stock and 68.46 raising the preload. You start adding mass (to the 166) and the delta is going to increase even further.

Sorry mate this is nonsense.

You cannot use this formula, since it is based on acceleration, we are talking about all conditions positive, zero and negative acceleration. That means that your "mass transfer" will be moving all the time you are riding the bike, this formula is designed predominately for braking distance calculations. The reason 4x4's have such long braking distance is because the Cof G is so high, so raising any part of the bike is not a good idea anyway.

If you doubt this put all of the values in your formula, rather than just some and then re-post the result.

If you didn't know that mass transfer happens in all sorts of directions during riding...wow, I can't believe that you're criticising my post (as an aside, using negative acceleration means you are raising a negative number...and -x*-x = x*x; i.e. the difference is greater than 'positive acceleration').

Even at rest there's acceleration. 9.8 m/s2.

I'd rather not drag this thread down with bickering, and since it's obvious that the physics are a subject that most lay people have problems with, I propose a practical experiment. Take a decently weighted length of whatever. Rest one end on a scale and hold the other end level with the scale. Start raising the end you are holding. See how much more weight ends up registering on the scale.

No offence mate but you are using the wrong formula for this particular argument.

This formula calculates the mass transfer as a result of acceleration and is nothing to do with moving forward the mass of some bags on a motorbike.

If you had the correct formula you would be able to provide a result, that is how maths (or in this case algebra) works, by entering values for each of the variables and obtaining an answer.

At best you could calculate the mass transfer at one particular rate of acceleration, so what use is that, since I am not always accelerating?

Posted

Go back to school Allan.

If a refrigerator falls on top of you with one end digging into your stomach and I lift the wrong end; tell me that it's not hurting you more. ie more weight is transferred to your stomach by lifting the back end.

Posted

Go back to school Allan.

If a refrigerator falls on top of you with one end digging into your stomach and I lift the wrong end; tell me that it's not hurting you more. ie more weight is transferred to your stomach by lifting the back end.

I really don't know what to say, you obviously have no idea what you are talking about. I asked you for an answer to this equation you quoted so eloquently and that answer would be a weight measurement (lbs/kg) and distance moved measurement (inches/mm) and now we are on to refrigerators.

Now most intelligent people would realise that their BS had been rumbled (by an Engineer as it happens) and disappeared, but you are either determined to convince everyone on this forum that you are a (DELETED)l, or that this is just a wind up that has gone on a bit too long.

I will be charitable and assume the latter.

However, if you are really convinced that this formula is correct put in all the values into it and post the result, any other rubbish I will ignore.

Posted

Go back to school Allan.

If a refrigerator falls on top of you with one end digging into your stomach and I lift the wrong end; tell me that it's not hurting you more. ie more weight is transferred to your stomach by lifting the back end.

I really don't know what to say, you obviously have no idea what you are talking about. I asked you for an answer to this equation you quoted so eloquently and that answer would be a weight measurement (lbs/kg) and distance moved measurement (inches/mm) and now we are on to refrigerators.

Now most intelligent people would realise that their BS had been rumbled (by an Engineer as it happens) and disappeared, but you are either determined to convince everyone on this forum that you are a complete fool, or that this is just a wind up that has gone on a bit too long.

I will be charitable and assume the latter.

However, if you are really convinced that this formula is correct put in all the values into it and post the result, any other rubbish I will ignore.

Replying the wrong person mate.

I've put an imaginary value in the acceleration value, if you want to put different values in and prove me wrong...knock yourself out. If you are not satisfied with that (and did not even notice the 9.8 m/s2 and understand the implication) than I'm sure the forum has determined the validity of your stance. The fact an English teacher provided a practical example (as well as me suggesting an experiment to determine if I am wrong) and yet you "an Engineer as it happens" (who none the less couldn't determine the cause of his vehicle's poor running) can not wrap your mind around it speaks volumes.

Posted

Enough. The original question was about lack of weight on front end with luggage and pillion. With just a pillion front end is light when accelerating. Upping the pre-load on rear will do very little to change that whatever formulas you come up with.

Posted

Enough. The original question was about lack of weight on front end with luggage and pillion. With just a pillion front end is light when accelerating. Upping the pre-load on rear will do very little to change that whatever formulas you come up with.

Than obviously he doesn't have to do it. He can either try and balance out the weight any way possible or be (DELETED) and think I'm full of (DELETED). I'm not riding with him so I don't care either way. Was merely trying to help him.

Posted

Enough. The original question was about lack of weight on front end with luggage and pillion. With just a pillion front end is light when accelerating. Upping the pre-load on rear will do very little to change that whatever formulas you come up with.

Than obviously he doesn't have to do it. He can either try and balance out the weight any way possible or be deleted and think I'm full of deleted. I'm not riding with him so I don't care either way. Was merely trying to help him.

Did not say it would do nothing to help, better than doing nothing but as pillions ass is directly over rear axle front is light under acceleration. Had front pop up with my lad on the back (65 kg ) pre-load one down from max, mild acceleration in second.

Posted

Go back to school Allan.

If a refrigerator falls on top of you with one end digging into your stomach and I lift the wrong end; tell me that it's not hurting you more. ie more weight is transferred to your stomach by lifting the back end.

I really don't know what to say, you obviously have no idea what you are talking about. I asked you for an answer to this equation you quoted so eloquently and that answer would be a weight measurement (lbs/kg) and distance moved measurement (inches/mm) and now we are on to refrigerators.

Now most intelligent people would realise that their BS had been rumbled (by an Engineer as it happens) and disappeared, but you are either determined to convince everyone on this forum that you are a complete fool, or that this is just a wind up that has gone on a bit too long.

I will be charitable and assume the latter.

However, if you are really convinced that this formula is correct put in all the values into it and post the result, any other rubbish I will ignore.

Replying the wrong person mate.

I've put an imaginary value in the acceleration value, if you want to put different values in and prove me wrong...knock yourself out. If you are not satisfied with that (and did not even notice the 9.8 m/s2 and understand the implication) than I'm sure the forum has determined the validity of your stance. The fact an English teacher provided a practical example (as well as me suggesting an experiment to determine if I am wrong) and yet you "an Engineer as it happens" (who none the less couldn't determine the cause of his vehicle's poor running) can not wrap your mind around it speaks volumes.

So no answer then......? You prove the validity of a formula by working it out and providing an answer.

I did notice you mentioned 9.8m/s2 which is close to the rate of acceleration due to earth's gravity...and?.

With regards to my bike, this turned out to be an intermittent electrical problem, a faulty electronic sensor, not my forte and understandably it foxed everyone, save for a man called Jo Modify who had seen the problem before. I don't profess to be a genius, I just have a little knowledge of the sciences.

Posted

Rear Height Adjustment

If your shock has a ride height adjustment and you wish to use it, you must measure the ride height (as for Rear Sag). We are recommending to make adjustments of only 5 to 10mm increments at a time. Larger changes will cause the bike to steer considerably quicker, and if you're not ready for it, you may find yourself in trouble! Raising the rear ride height will put more load on the front and may make it necessary to tighten up the front to compensate.

From here:

Posted

Rear Height Adjustment

If your shock has a ride height adjustment and you wish to use it, you must measure the ride height (as for Rear Sag). We are recommending to make adjustments of only 5 to 10mm increments at a time. Larger changes will cause the bike to steer considerably quicker, and if you're not ready for it, you may find yourself in trouble! Raising the rear ride height will put more load on the front and may make it necessary to tighten up the front to compensate.

From here:

http://www.suspensionshop.org/tech_suspension_setup.php

If you up the pre-load ride height stays the same. More weight on bike less compression on suspicion. Sorry but will do bugger all to prevent front end lifting.

Posted

Wow, there's a lot of experts on this thread who are giving out bad advice.

So expert they know more than Ohlïns.

NOTE!

The spring pre-load affects the ride height, it does not affect the spring stiffness. Therefore, on models with a linkage to the shock absorber, the suspension may actually feel harder when you reduce the pre-load and the shock absorber gets into the harder range of the link system.

I'm really trying to stay away from this thread because it's obviously toxic, but incorrect statements need to be addressed.

Posted

Wow, there's a lot of experts on this thread who are giving out bad advice.

So expert they know more than Ohlïns.

NOTE!

The spring pre-load affects the ride height, it does not affect the spring stiffness. Therefore, on models with a linkage to the shock absorber, the suspension may actually feel harder when you reduce the pre-load and the shock absorber gets into the harder range of the link system.

I'm really trying to stay away from this thread because it's obviously toxic, but incorrect statements need to be addressed.

No expert. Played around in my youth. Accept that upping preload is better than nothing. Rode the odd big bike in my time. Rear suspension dalliance will not stop the front lifting.

Posted

Back to actual actual topic. Any cool breaklight/indicator combinations available to this bike?

I did an integrated tail light/tail tidy at K-speed on Ram Intra for my 300R. Looks similar to the one in Dave's link (not sure if it's the same brand but you get the idea). Bike looks a lot better without those hideous stock turn signals. The total cost was a little over 2000 baht.

Posted

Been thinking about buying one, you guys who have a CB300, are you happy, ecstatic, disappointed or bored?

I think I would find it difficult to buy one.

If going for that sort of bike I would just buy a used CBR250 for 60 odd thousand. The used market has completely bottomed out on them.

The 300 is after all only 286cc and the same as the 250 in almost every other way.

If deciding to spend 135k or whatever they go for new, I would probably spend that on a nearly new Ninja 300 instead.

Posted

Been thinking about buying one, you guys who have a CB300, are you happy, ecstatic, disappointed or bored?

I think I would find it difficult to buy one.

If going for that sort of bike I would just buy a used CBR250 for 60 odd thousand. The used market has completely bottomed out on them.

The 300 is after all only 286cc and the same as the 250 in almost every other way.

If deciding to spend 135k or whatever they go for new, I would probably spend that on a nearly new Ninja 300 instead.

The CB has a more upright riding position than the CBR making it a slightly different bike and more comfortable for me, but I do get your point about price. There is a handlebar conversion kit I believe, will this change the riding position sufficiently?

Not to many raving about the CB so far, after only 3 hours of ownership it doesn't count and "happy for now" doesn't seem like a sign of ecxtacy (bloody spell check).

Also, I have ridden a CBR250 and it didn't exactly blow my mind, so I understand why people sell them.

Posted

Been thinking about buying one, you guys who have a CB300, are you happy, ecstatic, disappointed or bored?

I think I would find it difficult to buy one.

If going for that sort of bike I would just buy a used CBR250 for 60 odd thousand. The used market has completely bottomed out on them.

The 300 is after all only 286cc and the same as the 250 in almost every other way.

If deciding to spend 135k or whatever they go for new, I would probably spend that on a nearly new Ninja 300 instead.

The CB has a more upright riding position than the CBR making it a slightly different bike and more comfortable for me, but I do get your point about price. There is a handlebar conversion kit I believe, will this change the riding position sufficiently?

Not to many raving about the CB so far, after only 3 hours of ownership it doesn't count and "happy for now" doesn't seem like a sign of ecxtacy (bloody spell check).

Also, I have ridden a CBR250 and it didn't exactly blow my mind, so I understand why people sell them.

Nothing to be extremely excited by, dirt bikes and bigger bikes for that feeling.

Solid light city commuter which doesn't get stuck behind the cars and has enough power for the ring roads around BKK. Ideal bike for my daily commuting.

Posted

Been thinking about buying one, you guys who have a CB300, are you happy, ecstatic, disappointed or bored?

I think I would find it difficult to buy one.

If going for that sort of bike I would just buy a used CBR250 for 60 odd thousand. The used market has completely bottomed out on them.

The 300 is after all only 286cc and the same as the 250 in almost every other way.

If deciding to spend 135k or whatever they go for new, I would probably spend that on a nearly new Ninja 300 instead.

The CB has a more upright riding position than the CBR making it a slightly different bike and more comfortable for me, but I do get your point about price. There is a handlebar conversion kit I believe, will this change the riding position sufficiently?

Not to many raving about the CB so far, after only 3 hours of ownership it doesn't count and "happy for now" doesn't seem like a sign of ecxtacy (bloody spell check).

Also, I have ridden a CBR250 and it didn't exactly blow my mind, so I understand why people sell them.

I like my little CBR250. I think I may have bought the Givi topbox for it off you a year or so ago. I rack up 20km every morning and again every evening going through traffic and opening up a little bit when the highway becomes free for a few minutes. For that I think it is perfect and will keep it until I move jobs or house.

However buying again now, I would probably spend the same money I paid for it on a nearly new Ninja 300 instead.

Posted

Been thinking about buying one, you guys who have a CB300, are you happy, ecstatic, disappointed or bored?

I think I would find it difficult to buy one.

If going for that sort of bike I would just buy a used CBR250 for 60 odd thousand. The used market has completely bottomed out on them.

The 300 is after all only 286cc and the same as the 250 in almost every other way.

If deciding to spend 135k or whatever they go for new, I would probably spend that on a nearly new Ninja 300 instead.

The CB has a more upright riding position than the CBR making it a slightly different bike and more comfortable for me, but I do get your point about price. There is a handlebar conversion kit I believe, will this change the riding position sufficiently?

Not to many raving about the CB so far, after only 3 hours of ownership it doesn't count and "happy for now" doesn't seem like a sign of ecxtacy (bloody spell check).

Also, I have ridden a CBR250 and it didn't exactly blow my mind, so I understand why people sell them.

In my case "Happy for now" refers to my current situation, wants and needs. yours may differ.

Its a great bike for BKK. couldnt be happier. Faster than the scooters and nearly as nimble through traffic.. Believe me, the bulk of my riding is peak hr traffic jams.

But coming from a background of "big things" i.e Road Trains and V8 cars in my previous life back in the Australia im using it as training wheels, for however long it takes, till i'm in the right frame of mind to get something bigger. Having said that, it does such a damn good job of what I ask of it around BKK i might just keep it as well.

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