Why Is My Sonic Doing This?

[nellyp]

P.s. Oil measurement should be done on the centre stand, not the side stand. Let bike warm up for a bit then turn it off and leave it for at least 3 mins to allow oil to run down.

You know all this already, why I am telling you this.

This is a bit odd I just checked the oil(on the center stand ) and it appears to have mor eoil than the last time I checked it (on the center stand ).

I've also taken some pics that I'll try to upload of the oil around the engine. I've had a close look now and it appears that the oil is comming from the top joint of the engine (Valve cover) and has loads of burnt oil around the exhaust.

I'm off to see how much a new sprocket is. Would it make much difference if I changed the front instead of the back as it might mean that I don't need a chain. The chain is rigt at the front of the adjuster so there is loads to go.

[KRS1]

There are no front sprockets made that will give you the ratio of 2.93 that you would get with 15/44 sprockets.

12 and 13 teeth ratios:

15/44 = 2.93

13/36 = 2.769

12/36 = 3.0

15/36 = 2.4

its highly unlikely you will be able to find 12 or 13 teeth front sprockets. But you may be lucky and find the 12, id go for that one over the 13.

The ideal ratio is between 2.93 and 3.0 ......3.0 will be about 10kph slower top speed than 2.93...but 3.0 will have faster acceleration.

Either 2.93 or 3.0 will be a night and day difference over the 2.4 ratio you are pushing right now.

Look at the chain adjustment indicators, if the rear axle is all the way to the back right now...then the 44 might have a chance of fitting.

Dont go any smaller than 44 if you use 15 front

Edited February 16, 2013 by KRS1

[nellyp]

new socket with fitting 250 baht for the rear sprocket. Having it done tomorrow. I'm gonna take new photos as I cleaned the engine a went for a short run. No oil yet so I will see how long it takes to appear. I'm gonna go back to the garage that re-bored the engine and ask about the valves and carb. I'll do that tomorrow as well so can report back with a bit more info

[KRS1]

Take a picture of the carb, head gasket and valve cover gasket....need to see if its the original carb or N-Pro and whether its real or fake if its an N-Pro.

Take a picture of the muffler too please, especially the outlet hole.

Edited February 16, 2013 by KRS1

[nellyp]

There are no front sprockets made that will give you the ratio of 2.93 that you would get with 15/44 sprockets.

12 and 13 teeth ratios:

15/44 = 2.93

13/36 = 2.769

12/36 = 3.0

15/36 = 2.4

its highly unlikely you will be able to find 12 or 13 teeth front sprockets. But you may be lucky and find the 12, id go for that one over the 13.

The ideal ratio is between 2.93 and 3.0 ......3.0 will be about 10kph slower top speed than 2.93...but 3.0 will have faster acceleration.

Either 2.93 or 3.0 will be a night and day difference over the 2.4 ratio you are pushing right now.

Look at the chain adjustment indicators, if the rear axle is all the way to the back right now...then the 44 might have a chance of fitting.

Dont go any smaller than 44 if you use 15 front

Dude... you are a font of knowledge. I just went to sort out the job tomorrow, but I said I wanted a 42 tooth sprocket (obviously a brain fart). I hope they don't get one before II go tomorrow (they won't have any in stock). I am assuming that the bike will run more as intended once this is done but do not know if it will make a massive difference to my problem with top end, though I understand how it will affect the power delivery through the gears. Do you think it will make the bike faster in 5th than it is now in 3rd?

[KRS1]

There are no front sprockets made that will give you the ratio of 2.93 that you would get with 15/44 sprockets.

12 and 13 teeth ratios:

15/44 = 2.93

13/36 = 2.769

12/36 = 3.0

15/36 = 2.4

its highly unlikely you will be able to find 12 or 13 teeth front sprockets. But you may be lucky and find the 12, id go for that one over the 13.

The ideal ratio is between 2.93 and 3.0 ......3.0 will be about 10kph slower top speed than 2.93...but 3.0 will have faster acceleration.

Either 2.93 or 3.0 will be a night and day difference over the 2.4 ratio you are pushing right now.

Look at the chain adjustment indicators, if the rear axle is all the way to the back right now...then the 44 might have a chance of fitting.

Dont go any smaller than 44 if you use 15 front

Dude... you are a font of knowledge. I just went to sort out the job tomorrow, but I said I wanted a 42 tooth sprocket (obviously a brain fart). I hope they don't get one before II go tomorrow (they won't have any in stock). I am assuming that the bike will run more as intended once this is done but do not know if it will make a massive difference to my problem with top end, though I understand how it will affect the power delivery through the gears. Do you think it will make the bike faster in 5th than it is now in 3rd?

Yes top end speed will increase, provided the valves have the correct clearances.

Sitting upright probably something like:

42 tooth you'll probably hit 110-115 kph, maybe 120 kph in a full tuck.

44 tooth around 115-120kph, 125-130 kph in a full tuck.

[nellyp]

Take a picture of the carb, head gasket and valve cover gasket....need to see if its the original carb or N-Pro and whether its real or fake if its an N-Pro.

Take a picture of the muffler too please, especially the outlet hole.

sorry about the carb pics but I didn't want to take it off. As you can see the screwws in the carb look a bit f**cked so I didn't want to mess them up further. I'm gonna leave the panels off a go for a few Km tomorrow (after the sprocket is changed) to see where the oil is coming from.

[KRS1]

yep, the oil leak is coming from the valve cover gasket, you can see where they used a grey silicone gasket paste to overlay the original gasket. It doesnt look like a serious leak though, more like prolonged seepage of oil that essentially accumulated after time.

In image 4 the philips screw in the middle of all that brown crud is the air/fuel mixture screw (stock carb), when you take the screw out there is an o-ring inside that seals it off. The screw should be set somewhere between 2.75-3.5 turns out. Set the idle to 3.5k rpm before you adjust it, where ever it idles fastest when you turn it between 2.75 -3.5 turns....that is the sweet spot. Then readjust idle back down to 1.3k rpm.

Honda sells a gasket/oring set for that carb...

it contains :

1) that oring

2) the choke gasket

3) bypass valve diaphragm (not the needle slide diaphragm)

4) bowl gasket

If you are going to do the carb, you should also replace the needle and get new jets - just to make sure they didnt try to enlarge the jets by reeming them out. Different sized jets for this carb are almost impossible to find, the 115/35 are the sizes to use if you are truly at 150cc.

If you get the carb done id get a new needle at the very least. There should be 1 washer under the top of the needle, if there isnt then its running lean, if there is 2 then its running rich

a new slide diaphragm is very expensive for this carb and rivals the cost of a new Npro carb,

Change sparkplug to NGK CR9EGP, you'll have a better chance of breaking 130 kph...every little thing adds up.

Clean the mud off your radiator please.

[nellyp]

yep, the oil leak is coming from the valve cover gasket, you can see where they used a grey silicone gasket paste to overlay the original gasket. It doesnt look like a serious leak though, more like prolonged seepage of oil that essentially accumulated after time.

In image 4 the philips screw in the middle of all that brown crud is the air/fuel mixture screw (stock carb), when you take the screw out there is an o-ring inside that seals it off. The screw should be set somewhere between 2.75-3.5 turns out. Set the idle to 3.5k rpm before you adjust it, where ever it idles fastest when you turn it between 2.75 -3.5 turns....that is the sweet spot. Then readjust idle back down to 1.3k rpm.

Honda sells a gasket/oring set for that carb...

it contains :

1) that oring

2) the choke gasket

3) bypass valve diaphragm (not the needle slide diaphragm)

4) bowl gasket

If you are going to do the carb, you should also replace the needle and get new jets - just to make sure they didnt try to enlarge the jets by reeming them out. Different sized jets for this carb are almost impossible to find, the 115/35 are the sizes to use if you are truly at 150cc.

If you get the carb done id get a new needle at the very least. There should be 1 washer under the top of the needle, if there isnt then its running lean, if there is 2 then its running rich

a new slide diaphragm is very expensive for this carb and rivals the cost of a new Npro carb,

Change sparkplug to NGK CR9EGP, you'll have a better chance of breaking 130 kph...every little thing adds up.

Clean the mud off your radiator please.

Thanks again for all of this. I'm gonna have the sprocket done, but the guy who is doing it says I should have both sockets and the chain replaced. The chain will be too short so he said he will put a couple of links in for the same price. I have no idea how much it is for a full set, but I am trying to do this for not too much money, so I'm just gonna get the back sprocket replaced for now. I am going to have a bit of trouble setting the mixture as I don't have a rev counter on my bike. On cars I would just wind it all the way in the back it out till the revs and engine steadied. Perhaps I'll try that. I would love to sort out the needle too (by the washers), it seems a very odd way to set a standard for running lean etc. Can I do this with the carb on the bike? I'll get a new needle to do that soon.

For now though 1/ New sprocket, 2/ Try to set mixture, 3/ Spark plug

You are a star taking the time to give me this info, I promise I'll clean the radiator for you. What do you think about draining the oil and putting 20/50 in to stop the leak so much or maybe some engine sealer?

[KRS1]

You can do it with the carb on the bike as long as you can reach the top cap screws, only problem is you have to give those screws a good tapping before attempting to unscrew or else you may strip the heads, i am not joking. Place philips on screw and tap firmly with solid object.

I'd try to turn the top cap screws yourself first, only let each screw slip twice anymore than that stop.

Check the front sprocket and see if its really worn down and teeth are starting to slant, they're only around 80-120 baht

20/50 may work if you dont ride fast and heat the oil up too much, the surface plane between the valve cover and head are not seating evenly because of the old gasket and unevenly dispersed silicone .

Changing the gasket is easy. It'll take longer to scrape that old silicone off if you can talk your mechanic into scraping it off completely. That grey stuff sucks to scrape off, had to do a carb float bowl once and it took forever to get off completely if it gets into the ridges, that grey stuff aint no joke.

no engine sealer, try tightening the valve cover screws.

[nellyp]

You can do it with the carb on the bike as long as you can reach the top cap screws, only problem is you have to give those screws a good tapping before attempting to unscrew or else you may strip the heads, i am not joking. Place philips on screw and tap firmly with solid object.

I'd try to turn the top cap screws yourself first, only let each screw slip twice anymore than that stop.

Check the front sprocket and see if its really worn down and teeth are starting to slant, they're only around 80-120 baht

20/50 may work if you dont ride fast and heat the oil up too much, the surface plane between the valve cover and head are not seating evenly because of the old gasket and unevenly dispersed silicone .

Changing the gasket is easy. It'll take longer to scrape that old silicone off if you can talk your mechanic into scraping it off completely. That grey stuff sucks to scrape off, had to do a carb float bowl once and it took forever to get off completely if it gets into the ridges, that grey stuff aint no joke.

no engine sealer, try tightening the valve cover screws.

I'll do all of this (next weekend ) and let you know how it goes. I have already tried the cap screws and you are right they would not move. I'll soak them with some lube and give them a tap. I thought the front sprocket looked Ok so I'll leave it

\You are a gent

[BSJ]

Only one thing I can say: Ayaya yaya! Although it's best to hear it said.

[KRS1]

...one last recommendation, make sure you use the largest philips head that will fit. More than likely standard philips heads will be too small. Removing some of the pointy tip of the philips screwdriver also helps to get a grip on the philips head. (scrape on concrete)

quick firm (strong) hits on the philip screws to unset it. Just dont break it...lol

post picks of slide and needle when you get it out...good luck !

new harder black colored screws can be purchased from the dealer.

Edited February 16, 2013 by KRS1

[karlos]

This is a great thread, exactly what this forum should be about, members helping others.

I was away at a wedding today and wanted to add some input to this thread but KRS1 has been a great help to you.

Buy this man a drink if he pops by your way

[BSJ]

If your going to be working on motorbikes, you need one of these. An impact driver.

I bought my first one, made by Vessel, about 40 years ago and it's been my saviour 1000 times. It's still in the toolbox in Oz and my son is still using it.

I bought another one last year for use here......which is a Vessel too!

[nellyp]

If your going to be working on motorbikes, you need one of these. An impact driver.

I bought my first one, made by Vessel, about 40 years ago and it's been my saviour 1000 times. It's still in the toolbox in Oz and my son is still using it.

I bought another one last year for use here......which is a Vessel too!

I was going to make a comment about having one in the Uk but I couldn't remember what it was called. A great tool

[nellyp]

This is a great thread, exactly what this forum should be about, members helping others.

I was away at a wedding today and wanted to add some input to this thread but KRS1 has been a great help to you.

Buy this man a drink if he pops by your way

I can't thank him enough. He will probably be lost if he comes where I live

[nellyp]

Just went to pick up the bike he had put a 42 tooth on it when I specifically told him only a 44. Argument ensues as he feels I don't know what I'm talking about and only 42 for Sonic. I told him to change it, he has to go 50 km to buy (I can buy it in the town, so why can't he?) He will put the original back on Fine I say he shuts up and tells me to come back tomorrow.

I can get it done for 150 baht in a shop up the road. That's 100 baht cheaper

Why do they have to make life so difficult. If you ain't got the part, don't make decisions for me

[Briggsy]

Feelin' for ya.

If poss, do the Thai thing :-

Either

1) source the parts yourself

or

2) examine all the parts before fitting and stand over him and watch everything he does like a hawk.

It's ok, they all do it here.

By doing 2) above, I ensured he didn't put standard IRC tyres on my CBR when I had specifically sought out that shop as I wanted Michelin's.

[dave_boo]

Definitely about buy your own parts...I have a Vortex sprocket inbound for that very reason. Hopefully it doesn't mess up my acceleration too much as now I think about it I may have gone overboard...

[nellyp]

Fitting my sprocket part 2

Took from first garage with old sprocket re-fitted

Went to second garage, having made sure they had a 44 tooth sprocket....Yes yes no problem

Took off back sprocket,

I asked about chain

They said better to have new

I said how much for a new set (2 sprockets and chain) fitted.

320 Baht

OK (I was paying 250 for rear sprocket at 1st garage)

They strip the bike down

(replaced screws on the Carb cap...10 baht)

No 44 tooth sprocket-----Can we put a 45 tooth sprocket on for you?

No I want a 44 tooth sprocket

You will have to wait for a week

Wicked

Bike rebuilt and off to have a beer.

What difference will a 45 tooth rear sprocket make?

I have been advised to have an NGK CR9EGP plug fitted they only had a F1 CR8EGP, is this an equivalent plug or the same as the Denso I have on it now.

I am seriously thinking of buying the parts and doing this myself. I know how to do it, and know that all the nuts will be easy to remove and replace as they have just been done. But as the fitting is next to nothing ios it worth it?

Edited February 17, 2013 by nellyp

[KRS1]

45 tooth = 3.0 ratio , will be a bit peppier in low and mid range and run at a bit higher rpm than 44 and about 5-8 kph slower top end than 44....its the same ratio as 14/42 = 3.0 or 12/36 =3.0

45 is ok

cr9EGP - the EGP means its a platinum tip needle type electrode, the 8EGP is a different temperature, ive tried it before and throttle response isnt as good as the 9EGP....A CR9EIX designates a needle type Iridium sparkplug 400-500 baht, platinum is good enough. Same design as EGP, but uses Iridium instead. As for the F1 CR8EGP, never heard of an F1 designation. Only NGK.

Sparkplug and carb are easy to do, if your sure you can get the carb top cap off go for it. Finger tighten the spark plug as much as you can then tighten about 0.75-1.00 of a turn do not over tighten., and make sure the sparkplug wire ''snaps" into place when putting it back on.

When you remove the carb top cap, hold down the cap as you remove the last screw, there's a spring directly beneath it and will push up, its not strong and wont go flying but it will push upwards.

1) remove the spring, then remove the slide and diaphragm , it will be all one piece and the needle will be attached.

2) reach into the slides hole with a pair of needle nose pliers and extract the needle retainer and remove the needle. You may have to turn it a little, memory is fuzzy.

3) inspect rubber diaphragm for pin holes

4) inspect slide for excessive wear

5) put needle and retainer back into slide

6) make sure to line up the notch on the diaphragm with the notch on the top of the carb.

7) stick spring in

8) put center notch on bottom of top cap into the springs hole and put on carb, then screw in.

Make sure everything is very clean before putting it back together and dont let any dirt fall into the carb...and make sure your philips head is a big one.

If you take it to a shop and let them do the carb to clean and rebuild it, bring them some fresh benzene/gasohol to clean it with , its almost guaranteed that they will use old benzene to clean it that will be dirtier than the actual carb...carburetpr cleaner spray is very hard to find in thailand....they'll probably use compressed air to blow out the jets and bypass holes, thats why you need fresh benzene. Acetone or rubbing alcohol will also work.

Edited February 17, 2013 by KRS1

[nellyp]

45 tooth = 3.0 ratio , will be a bit peppier in low and mid range and run at a bit higher rpm than 44 and about 5-8 kph slower top end than 44....its the same ratio as 14/42 = 3.0 or 12/36 =3.0

45 is ok

cr9EGP - the EGP means its a platinum tip needle type electrode, the 8EGP is a different temperature, ive tried it before and throttle response isnt as good as the 9EGP....A CR9EIX designates a needle type Iridium sparkplug 400-500 baht, platinum is good enough. Same design as EGP, but uses Iridium instead. As for the F1 CR8EGP, never heard of an F1 designation. Only NGK.

Sparkplug and carb are easy to do, if your sure you can get the carb top cap off go for it. Finger tighten the spark plug as much as you can then tighten about 0.75-1.00 of a turn do not over tighten., and make sure the sparkplug wire ''snaps" into place when putting it back on.

When you remove the carb top cap, hold down the cap as you remove the last screw, there's a spring directly beneath it and will push up, its not strong and wont go flying but it will push upwards.

1) remove the spring, then remove the slide and diaphragm , it will be all one piece and the needle will be attached.

2) reach into the slides hole with a pair of needle nose pliers and extract the needle retainer and remove the needle. You may have to turn it a little, memory is fuzzy.

3) inspect rubber diaphragm for pin holes

4) inspect slide for excessive wear

5) put needle and retainer back into slide

6) make sure to line up the notch on the diaphragm with the notch on the top of the carb.

7) stick spring in

8) put center notch on bottom of top cap into the springs hole and put on carb, then screw in.

Make sure everything is very clean before putting it back together and dont let any dirt fall into the carb...and make sure your philips head is a big one.

If you take it to a shop and let them do the carb to clean and rebuild it, bring them some fresh benzene/gasohol to clean it with , its almost guaranteed that they will use old benzene to clean it that will be dirtier than the actual carb...carburetpr cleaner spray is very hard to find in thailand....they'll probably use compressed air to blow out the jets and bypass holes, thats why you need fresh benzene. Acetone or rubbing alcohol will also work.

I figure no problem with the carb as i had them alter the screws in the cap and had the needle et al out for a look. I had no idea what i was looking for as to wear on the needle. I can take the cap off easily now and know what I am looking at (I downloaded a cbr 150r manual that anybody is welcome to, just PM me).

Spark plug is no problem I've replace and cleaned hundreds

I am also thinking about doing the full set of sprockets and chain, I can do it myself as I've seen them do it in the shop now, I was a bit worried about the chain link but they have freed that up as well. This shop looks quite good though, oiled and greased everything they took off and put back on. Checked brakes, oil levels as they went. I may just let them get on with it, 320 baht bought and fitted (full set) and clean hands.

I have told them to get me the NGK plug you recommended so I will wait for that. I'll do this in stages so I can comment on any improvement

I really can't thank you enough for all this info, and workshop like advice.

[KRS1]

Id let them do it, hell i dont even want to do it, its a messy job. Sparkplug is easy enough though. Try sticking some good oil in there, i like Castol Power 1 but theres a lot of fake stuff out there. D.I.D. makes a good chrome chain, don't go to cheap on the chain, the cheap ones stretch easily if you ride hard.

The cbr 150 has a different head, try to find the cbr 125 manual, check out the canadian forums.

Good luck

[nellyp]

Id let them do it, hell i dont even want to do it, its a messy job. Sparkplug is easy enough though. Try sticking some good oil in there, i like Castol Power 1 but theres a lot of fake stuff out there. D.I.D. makes a good chrome chain, don't go to cheap on the chain, the cheap ones stretch easily if you ride hard.

The cbr 150 has a different head, try to find the cbr 125 manual, check out the canadian forums.

Good luck

You asked me to post pics of the needle. I took it out yesterday so you can see it. I'll have a look for the manual later. is the engine exactly the same?

[loserlazer]

I think your sonic is bored in the middle of nowhere buddy and this is why it is doing this!

Just drive it in bangkok rush hour traffic two doses morning and evening and it will wake up:lol:

[KRS1]

Id let them do it, hell i dont even want to do it, its a messy job. Sparkplug is easy enough though. Try sticking some good oil in there, i like Castol Power 1 but theres a lot of fake stuff out there. D.I.D. makes a good chrome chain, don't go to cheap on the chain, the cheap ones stretch easily if you ride hard.

The cbr 150 has a different head, try to find the cbr 125 manual, check out the canadian forums.

Good luck

You asked me to post pics of the needle. I took it out yesterday so you can see it. I'll have a look for the manual later. is the engine exactly the same?

Needle looks ok, not worn, looks like its already been replaced actually. The CBR 125 engine is the same as the Sonic engine. The CBR 150 has a different head with 4 valves vs 2 for the sonic, the magneto, stator and CDI are also different between the 2 bikes, and also has different timing. The exhaust pipe on the CBR 125 uses the exhaust from the cbr 150 also, it's a little longer vs the shorter Sonic exhaust downpipe.

Edited February 19, 2013 by KRS1

[nellyp]

I think your sonic is bored in the middle of nowhere buddy and this is why it is doing this!

Just drive it in bangkok rush hour traffic two doses morning and evening and it will wake up:lol:

It's been there and done that. It didn't like it, and neither did the owner.

[nellyp]

Delay on the job. I can't find the sprocket I want (44 tooth) so I am trying to find somewhere to buy a set online. My closest big town is Roiet and they only have 45 rear sprockets, I thought about going 12 front and 36 rear but I can't find a 12 either...oh to live in a civilized area.

P.S I've been riding with the panels of (playing with carb) and the bike seems to have more pep.

[KRS1]

Im not 100% sure, but a cbr 150 rear sprocket may fit, the stock size is 44...

The rear brake disc fits on the front of a sonic, so the sprocket may be smaller, but it couldnt hurt to ask.

Probably be better to place them on top of each other at a shop to see. Then you'd know for sure, im thinking its smaller though.

Chain size would also have to be the same.