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 cam chain stretch

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becoyote




PostSubject: cam chain stretch   Mon Mar 20, 2017 9:10 am

How do you measure for stretch? Can't find it in the manual.

Thanks!
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66T

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PostSubject: Re: cam chain stretch   Tue Mar 21, 2017 5:36 pm

How much work has your bike done? If it's a lot, don't hesitate. Change the chain and inspect the tensioner. Valves and pistons aren't a good look after they've tangled!
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becoyote




PostSubject: Re: cam chain stretch   Tue Mar 21, 2017 10:17 pm

18k on it. I bought it last year with 16k.
No bad noises but when I did the valve check I noticed all the timing marks weren't lining up.
I ordered A manual cam chain tensioner. Hoping it was just the automatic one not doing its job.

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CRFan1




PostSubject: Re: cam chain stretch   Wed Mar 22, 2017 11:09 pm

Very unlikely that the cam chain has stretched....those HyVo chains are designed to last the life of the engine. I would suspect the tensioner....
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becoyote




PostSubject: Re: cam chain stretch   Wed Mar 22, 2017 11:19 pm

That is what I am hoping. It was an 08 with the original tensioner. I saw that yamaha has an updated one but I went for the manual one anyway.

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johnkol




PostSubject: Re: cam chain stretch   Thu Mar 23, 2017 6:37 am

These are not roller chains, they are Morse chains, they don't really stretch.

If the timing marks were not lining up, that means that at least one of the cams jumped teeth. It may have been due to a chain tensioner malfunction, but usually this is the result of a wrong installation.
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becoyote




PostSubject: Re: cam chain stretch   Thu Mar 23, 2017 8:54 am





With the crankcase timing mark in position, this is how far off the marks on the cam sprockets were.

If I lined up the marks on the sprockets then the mark wasn't even visible through the crankcase cover.

I'm pretty sure this is the first time the bike has been opened.
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johnkol




PostSubject: Re: cam chain stretch   Thu Mar 23, 2017 11:06 am

These timing marks don't look like they're one full tooth apart. Can you feel any play in the chain? There shouldn't be any.
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becoyote




PostSubject: Re: cam chain stretch   Thu Mar 23, 2017 12:14 pm

There was no slack in the chain bewen the sprockets and there really isn't much of the chain exposed other than that.

Ive already pulled the old tensioner.

I'll just go ahead and reassemble with the new manual tensioner once it gets here without doing the chain
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johnkol




PostSubject: Re: cam chain stretch   Thu Mar 23, 2017 1:23 pm

Looking at the picture again more closely, it does appear that the timing marks could be just one tooth off. Did you attempt to move one camshaft by one tooth to see if the timing marks precisely align?
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becoyote




PostSubject: Re: cam chain stretch   Thu Mar 23, 2017 8:09 pm

Not yet. I have to adjust the valves. I'll try to get it all lined up after that. Waiting on the new rensioner before I do anything else.
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becoyote




PostSubject: Re: cam chain stretch   Wed Mar 29, 2017 11:13 am

Installed a manual tensioner.

Haven't restarted the bike yet but things are lining up the way they should.
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66T

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PostSubject: Re: cam chain stretch   Wed Mar 29, 2017 7:16 pm

Sorry to disagree, but I had to replace my chain at 26k km. Maybe a lot of slow running wears them...
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