strange engine noise.

[Geoffrey25]

Hi all I am new to this site this my first post so here we go ,I have had bikes on the road for over 30 years and had all manner of bikes I have just recently purchased a 2009 ybr125 with 17000 on the clock.This is my smaller bike I use through the winter months to save my 650 bandit any way the ybr is fairly clean and tidy looking it rides quit well all gears select well ,but there is a noise coming from what seems the left side of the engine when riding over 30 mph it sounds like rumbly front sprocket kind of noise.Now since hearing this noise I have changed chain and sprockets checked out the clutch checked valve clearance and cam chain tensioner at first I thought I had sorted it but the noise is still there,but it sounds good enough when on idle and when you rev it in neutral it just does it when riding.My question is I have never heard the engine of a ybr 125 before so I am not sure if there is a problem with it or they are just a noisey sounding bike , I have read that they can develop a common rumble sound just wondering if anyone has experienced any thing similar with their ybr many thanks joe.

[Stu]

Hi Joe welcome to the forum

Pop over to newbies and say hello

Have you tried pulling the clutch in while riding to see if the noise stops or carries on?

This will determine whether its engine related or drive train

My initial thoughts are wheel bearings or output shaft bearing

[TimR]

Stiff/broken link on chain

Loose front sprocket

As only when driving i would limit my prelim search to drive chain area

[Stu]

Stiff/broken link on chain

Loose front sprocket

As only when driving i would limit my prelim search to drive chain area

 

Tim he has changed all that since the noise started with no difference

[TimR]

Stiff/broken link on chain

Loose front sprocket

As only when driving i would limit my prelim search to drive chain area

 

Tim he has changed all that since the noise started with no difference

Oops read that as checked not changed ffs specsavers here i come or stop masterbating....decisions

[TimR]

Check for anything catching on chain ie chain guard bent/split ... stone ir similar caught in its path along swingarm guide

[Geoffrey25]

Hi stu thanks for speedy reply pulling clutch in doesn't change sound did you mean con rod bearing or crankcase bearing I have never had a main bearing go ,but I have been told you can feel it through foot pegs and handle bars engine sounds good when stationary only really does it from 30 mph onwards many thanks joe.

[Stu]

No conrod and main bearings are fine as the sound carries on when you pull the clutch

I would start with wheel bearings make sure they are OK first they are the cheapest and easiest to look at

The output shaft bearing is the one behind the sprocket, The shaft the sprocket goes on is the output shaft

[Geoffrey25]

Ok stu thanks for that hopefully it will last for the better weather then it could mean engine out and on the bench job I am quite handy with spanners but have never done an out put shaft bearing before if its not too difficult I will give it a go thanks again joe.

[Stu]

As I say check other things like wheel bearings first as they can all sound similar

Let us know the outcome

I have known output shaft bearings start humming and last for 40k!

[Tango]

Yeah, I'd be checking wheel bearings.....

[Guest]

Check cush drive too. Don't know if ybr just has the simple rubbers?