Author Topic: Cam Chains and Valve Guides  (Read 2920 times)

flyingbiker

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Cam Chains and Valve Guides
« on: March 17, 2014, 09:09:59 PM »
Hi all, just going over my bike which has done 4500 miles.
My first problem is the cam chains, most of the time they are loose to the point they are hitting the covers, but at certain points of the revolution they are so tight they feel like they are about to be snapped, any ideas? see photos.

Secondly have a look at the photo looking into the exhaust valves and let me know what you think is letting the oil in.

Cheers.

flyingbiker

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Re: Cam Chains and Valve Guides
« Reply #1 on: March 17, 2014, 09:10:34 PM »
next photo!

flyingbiker

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Re: Cam Chains and Valve Guides
« Reply #2 on: March 17, 2014, 09:11:05 PM »
last one!

Miti

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Re: Cam Chains and Valve Guides
« Reply #3 on: March 21, 2014, 10:08:20 AM »
Hi Simon;

Hope the chat helped the other night...

What was the result after correct adjustment of the chains..?  Still tight-loose-tight loose..?

Jeff
1974 Triumph T160 Trident (New Project)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Red Sport)
1982 Hesketh V1000 (Production/Development Engine)

flyingbiker

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Re: Cam Chains and Valve Guides
« Reply #4 on: March 22, 2014, 07:13:45 AM »
Hi Jeff.

Chat was very helpful, the first thing i did was check the chain on the right hand vertical run when the top run was bow tight, just as we expected the rest off the chain is hanging off!
So it looks like problem solved.

Thanks again.

Tig

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Re: Cam Chains and Valve Guides
« Reply #5 on: March 24, 2014, 07:21:36 PM »
Hi Jeff

Can you expand on this please..

Tig

Miti

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Re: Cam Chains and Valve Guides
« Reply #6 on: March 30, 2014, 11:42:19 PM »
Can you expand on this please..

Certainly Tig...  Simon and I discussed camchain tension and the effect that the action of the valve-springs/cams has on the cam-chain tension...  There are periods in the rotation where the springs are fully extended and the lobes facing away from the followers, so the valvegear doesn't additionally contribute to camchain tension at this point...  Conversely, there are periods where both cams are bearing down on the valve-springs and this adds significantly to the camchain tension...

Simon had examined the camchain tension on his V1000 and found that both were quite loose.  He tried to tension them, but didn't pre-position the engine before doing this... I've been there and the results are less than satisfactory - to say the least! ::)

I'm hoping that correct pre-positioning and adjustment has sorted the problem for Simon... It didn't for me.  I found that my camchains had definite tight/slack spots - particularly the rear one.  I suspect they had been maladjusted before... So, I've replaced both chains on my V1000 and the slack/tight problem is sorted.   ;D

Mine is taxed from Tues, so let's hope the weather smiles for me...

Jeff
1974 Triumph T160 Trident (New Project)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Red Sport)
1982 Hesketh V1000 (Production/Development Engine)

Tig

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Re: Cam Chains and Valve Guides
« Reply #7 on: April 01, 2014, 05:54:26 PM »
Ah yes... as I recall both lobes facing outwards towards the top?

Miti

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Re: Cam Chains and Valve Guides
« Reply #8 on: April 01, 2014, 08:17:34 PM »
Yep... same as position for shim clearance measurements...

It's all in the owner's manual, y'know...

Jeff
1974 Triumph T160 Trident (New Project)
1981 Yamaha XS1100 Sport (Trike Project)
1981 Yamaha XS1100 Sport (Red Sport)
1982 Hesketh V1000 (Production/Development Engine)