cam chain - Horizons Unlimited

**FredXTZ** · #1 3 Dec 2002

When I put a new piston in @ 58.000 km. I forgot to renew the cam chain, Somebody told me afterwards. Now a friend has done it and found out that the new chain is abt. 1 cm. shorter, so it's probably necessary. However, shouldn't we renew the sprockets too, like with the drive chain & sprockets ?

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Fred, XTZ660, Holland.

**aukeboss** · #2 3 Dec 2002

Wear of the camchain happens mostly inside the chain at pin / blade connection, as the lubrication of the chain / sprocket surfaces is excellent inside the engine.
This is contrary to the drive chain where the environment for the chain / sprocket contact surfaces is adverse with dirt, often no lubrication etc and where, with modern O-ring chains the lubrication of the pins and rollers is excellent.

So, no need to renew the timing chain.

Auke

**FredXTZ** · #3 3 Dec 2002

Hé Auke, hoef jij niet te werken ?

My question was not whether to replace the chain or not, I'm convinced that it's useful
because Peter has bought a new one and it's about 1 cm. shorter that the old one. So the camshaft timing is about 0,5 cm. late !
But if the chain is lengthened, the distance between the rollers is bigger. Has the distance between the sprocket pinions also become bigger by following the worn chain ?

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Fred, XTZ660, Holland.

**aukeboss** · #4 4 Dec 2002

1. Jein
2. You're right. This does have a certain 'medicijnmangehalte'. But, I never heard of someone (having to) replace the sprockets.

An explanation might be that with increasing wear on the chain, as distance between pins increases, the chain 'moves up' on the triangular teeth of the sprokets so compensating for increasing distance AND timing difference.

Auke

**david lambeth** · #5 8 Dec 2002

Hi
You dont need to replace either of the sprockets as they are incredibly hard and the lower one is not available anyway.
Beware...do not use anything other than a genuine Yamaha cam chain.
David Lambeth

[This message has been edited by david lambeth (edited 08 December 2002).]