Alright chaps. So riding home from work my xt 125 2010 suddenly starts a loud knocking coming from the bottom end of the engine. It happens when the bike is moving past 15 mph, not when idling. Ideas ?

I'm not a mechanic but I'm eager to split the engine and have a look and I've learnt slowly but surely. Would it be cheaper to buy a new bottom end or the parts depending on what it is?

does it depend on revs or road speed.

ride with the clutch in over 15 mph and see if it still knocks

Pretty sure it's speed drewpy but I will double check

could be a stiff link in your chain, see if the chain links have any kinks when between the sprockets ?

Can be quite commonplace if you ignore your chain oiling in winter !

You'll hear it when the engine is under load...and it'll be hard to hear with the throttle closed

Yeah I thought of that airhead, thanks though. I do keep on top of my chain maintenance. It definitely is coming from the bottom end and is a really loud knock

When the engines at idle , and you rev it , is noise still there ,?

No it isn't blackhat, only when moving

Yeah I thought of that airhead, thanks though. I do keep on top of my chain maintenance. It definitely is coming from the bottom end and is a really loud knock

Double check the chain and sprockets, remove the front sprocket cover and check inside it, spin the rear wheel by hand while watching the front sprocket to see if the chain jumps or theres a stiff link, you may not see it at the rear spkt due to the larger radius

Can you feel the knock through the footpegs ?

At least we know its not the engine , as kev says thru the footpegs, = sprockets or chain, My tiger did this on over-run last year,

it turned out front sprocket was hooked teeth,,

Hi there how do I start a new topic

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I was trying to rule out big end or main bearing trouble Blackhat ,

I was trying to rule out big end or main bearing trouble Blackhat ,

It can't be the engine, its transmission related

[ Quote kevthe rev , rule out big end ]

So was I kev "

Sorry chaps I've been a busy bee. There's no stiff links in the chain, I know by only saying knocking you can't imagine my problem clearly but the noise is certainly coming from the bottom end of the engine, not the front sprocket/chain.

I can't really feel it at the foot pegs but it's more of a loud slap and I don't think the vibrations would be strong enough to feel if that makes sense.

if you pull the clutch in does it quieten ,?

No it doesn't blackhat, the noise kicks in at around 15mph, at first it was 25mph, and stops again when the bike slows down past 15mph

so if it doesn't knock at standstill,with the engine running, its not the big ends!! As per my post #13

Mains umder load?

Balancer shaft "