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YBR 125 stutters as if about to stall when pulling away + engine rattling when accelerating


Yamaheart
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Hi, just wondering if anyone could offer any advice for some problems I’m having on my bike,


I bought it about eight months ago, it’s a 2010 YBR 125cc (Custom but I believe mechanically it’s the same as the YBR)


Couple issues:

1 - When I try to pull away in first gear the engine stutters as if its about to stall out, but then it recovers. It’s hard to describe, but it’s easily noticed if you get on it and ride it. This only seems to happen after the bike has warmed up after a few mins and it doesn’t seem to happen if I pull away going downhill, which isn’t very often. Makes riding in town awful.


I have been riding for quite a few months and don’t think it's my technique, because no matter how much throttle I give, or how slowly I feed out the clutch lever it still seems to do it. My theory is that’s it’s the clutch, but I don’t know. Someone told me they have the same problem on their 2015 YBR and it’s still there after replacing all clutch plates, springs, clutch cable, and oil


2 - Weird clicking/rattling noises, coming from the engine I think and it only happens when I am accelerating. It’s just like a constant clicking. It seems to be louder in the higher gears.


Thanks very much in advance.

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Weeelll...


1. I did notice when I was riding my wife's YBR125 (to the MOT, which it failed!) that the chain was a bit slack; I noticed this because the power delivery feels bit 'wrong' - while the chain is flapping around getting tensioned up after you pull away. This is kind of like a juddering. I'm pretty sure it will go away when the chain next gets tightened up.


So if you haven't checked it already, I would suggest you check the chain tension (and give it a clean and lube while you are there).


2. Assuming that the 'weird clicking and rattling noises' didn't happen before I'd guess (a wild guess) that it's the valve clearance that needs adjusting. The YBR125 has manual-type screw valve adjusters which can work loose. If they do it will sound like the proverbial bag of spanners.


It could (of course) be something else - it's pretty hard to say without being there IRL.


NB. if you put your vague location in your profile then if you are really lucky someone might come and have a listen or at least might know a reputable place locally where you can take it.

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The idea of a chat forum is to chat . I hope you are not another person who registers , asks one vague technical question and is then never heard of again . So , does it smoke ?

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Hi guys, thanks for the responses. Wasn't expecting any.

 

Weeelll...


1. I did notice when I was riding my wife's YBR125 (to the MOT, which it failed!) that the chain was a bit slack; I noticed this because the power delivery feels bit 'wrong' - while the chain is flapping around getting tensioned up after you pull away. This is kind of like a juddering. I'm pretty sure it will go away when the chain next gets tightened up.


So if you haven't checked it already, I would suggest you check the chain tension (and give it a clean and lube while you are there).


2. Assuming that the 'weird clicking and rattling noises' didn't happen before I'd guess (a wild guess) that it's the valve clearance that needs adjusting. The YBR125 has manual-type screw valve adjusters which can work loose. If they do it will sound like the proverbial bag of spanners.


It could (of course) be something else - it's pretty hard to say without being there IRL.


NB. if you put your vague location in your profile then if you are really lucky someone might come and have a listen or at least might know a reputable place locally where you can take it.

 

It's definitely not the chain as I just recently replaced it (I had been commuting 10 miles a day solid everyday throughout winter without realising chain cleaning and lubrication was a thing...)


Also about the clicking, a new noise got thrown into the mix last week after I set a new land speed record of 61mph on a dual carriageway.


Thanks for the heads up on the location, I've updated it. (Hertfordshire)

 

Does it smoke at all ?

 

It does not smoke no

 

Has it always done this or is it a new development ?


have both occurences appeared at the same time ?


does it only stutters after you have stopped using the choke/ half choke ?

 

It's been doing both for months. Fairly sure it was NOT there when I bought it though. They didn't appear at the same time, no - the rattling is a newer issue. Could it be related to the neglected chain? My bike doesn't have a choke.


Side note (could be related): I took off the air filter just to have a look, but as soon as I took off the cover that goes on top of it, a load of oily crap started leaking out... It was a complete mess to clean up and the "crankcase breather" also needed cleaning out because it had completely filled up (that might've been what overflowed?). I also noticed it's a genuine Yamaha filter, now I could be wrong but who knows if it has ever been replaced (can't find anything in the one bit of service history I have. Looking at the past MOTs, it appears the bike wasn't maintained great).


Picture here if anyone's interested:



And I was thinking of getting some petrol injection cleaner. Was suggested by someone and it may help?


Edit: Since I got the bike I've been putting fuel from Morrison's in it. Could that be a problem?

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Ok, apologies for my earlier comment regarding your lack of response, I was feeling a little annoyed about some other first time posters who use this forum once only to seemingly demand technical help and then fail to acknowledge our efforts. So welcome to the forum . The reason I needed to know if it smoked is that from experience with a colleagues bike and some posts here , I have become aware that YBRs might be prone to excessive cylinder wear and piston ring failure. The poor performance, ticking noises and increased discharge of oil vapour from the crankcase breather all point in this direction BUT if it isn't smoking then I doubt that this is actually the case . Other likely causes of ticking noises can be flappy tappets but more usually tappets close up . A leaking exhaust can produce a metallic ticking sound as can a loose camchain . A lack of oil to the top end can create worn camshaft journals which would also affect running and produce noise . The thing that all of these possibilities have in common is that the only sure way to find out what's wrong is to methodically strip down the engine starting with the top end , inspect and measure all components in accordance with the specifications in the manual and replace as required. If you buy a Haynes manual and follow it carefully you will find this to be a very rewarding experience that will set you on the right path to becoming a good motorcycle mechanic . By the way , if your engine turns out to be trashed you could always buy a generic Chinese YBR style engine brand new for as little as £200 . After all, the YBR is not actually made by Yamaha in Japan. It's a Chinese Jianshe built to ( presumably ) a slightly higher standard with a higher price tag to match . So sticking a Chinese engine in it wouldn't make a lot of difference.

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my ybr stutters when i don't give enough throttle when i release the clutch, it shakes a bit under 3000 rpm's if that makes sense. If i give proper throttle +4000 rpm's it's stutter free and the clutch is all good. It depens how fast you engage the clutch as well.


Fresh fully synthetic oil will help with the smoothness of the clutch.

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Ok, apologies for my earlier comment regarding your lack of response, I was feeling a little annoyed about some other first time posters who use this forum once only to seemingly demand technical help and then fail to acknowledge our efforts. So welcome to the forum . The reason I needed to know if it smoked is that from experience with a colleagues bike and some posts here , I have become aware that YBRs might be prone to excessive cylinder wear and piston ring failure. The poor performance, ticking noises and increased discharge of oil vapour from the crankcase breather all point in this direction BUT if it isn't smoking then I doubt that this is actually the case . Other likely causes of ticking noises can be flappy tappets but more usually tappets close up . A leaking exhaust can produce a metallic ticking sound as can a loose camchain . A lack of oil to the top end can create worn camshaft journals which would also affect running and produce noise . The thing that all of these possibilities have in common is that the only sure way to find out what's wrong is to methodically strip down the engine starting with the top end , inspect and measure all components in accordance with the specifications in the manual and replace as required. If you buy a Haynes manual and follow it carefully you will find this to be a very rewarding experience that will set you on the right path to becoming a good motorcycle mechanic . By the way , if your engine turns out to be trashed you could always buy a generic Chinese YBR style engine brand new for as little as £200 . After all, the YBR is not actually made by Yamaha in Japan. It's a Chinese Jianshe built to ( presumably ) a slightly higher standard with a higher price tag to match . So sticking a Chinese engine in it wouldn't make a lot of difference.

 

Appreciate the response, but that’s definitely not something I’d feel comfortable doing considering it’s my only method of transport. I completely get that it will improve my overall skills on working with bikes though. It’s a bit of a shame that it could well be anything at all really. I just hope that I am not causing any damage by continuing to ride

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my ybr stutters when i don't give enough throttle when i release the clutch, it shakes a bit under 3000 rpm's if that makes sense. If i give proper throttle +4000 rpm's it's stutter free and the clutch is all good. It depens how fast you engage the clutch as well.


Fresh fully synthetic oil will help with the smoothness of the clutch.

 

Yeah I was going to go with fully synthetic oil the next time I changed it. I was also going to clean the oil strainer

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I think that [mention]fastbob[/mention] has mentioned all the usual common causes.......I'd definitely be checking for holes in the header pipe or leaks around where it goes into the cylinder head.....This can cause a ticking noise and running issues. ......and, given that you say that the maintenance hasn't been great, the header can rot through..... :wink:

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