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Main Area => General GS500 Discussion => Topic started by: malcman on March 02, 2009, 10:39:34 AM

Title: cam chain tension & clearance questions
Post by: malcman on March 02, 2009, 10:39:34 AM
So I'm on march break at the moment and finally have time to start looking into the GS. When I bought the bike, the only time it ran was when I went to look at it and it took a very very very long time for it to start. I wanted to make sure that it did run before I bought it but knew that there was something wrong because of the fact that it took so long to start. Now today I took the valve cover off and started to check valve clearances, and I can't even fit a 0.20mm feeler gauge between the shim and the cam on the intake( I had the cam lobe position like it says in the manual, and I even tried it at some other positions just to make sure) and I never even bothered to check the exhaust yet. I'm assuming that the valves are just way too tight for it to start, could I be correct in this assumption? I have some spare shims from my parts motor that I'm gonna try and see if I can get them within spec. Also, my bigger concern is the cam chain tension. At some points of the motor revolution the chain is tight like it should be, but then at some points in the revolution the chain is pretty slack. Should the chain have equal tension during all points of the motors revolution? I would have thought yes but I could be completely wrong. Again, I could take the tensioner from my parts motor and try if the consensus is that the chain should have equal tension at all times in the motors rotation. Here's a picture of the chain, 2 pictures are when it is slack, the other is when it is tight.

Slack
(http://img.photobucket.com/albums/v239/malcman/IMG_0739.jpg)

Slack
(http://img.photobucket.com/albums/v239/malcman/IMG_0740.jpg)

Tight
(http://img.photobucket.com/albums/v239/malcman/IMG_0742.jpg)

Title: Re: cam chain tension & clearance questions
Post by: GeeP on March 02, 2009, 11:25:20 AM
Check your chain tensioner and tension guide.  It might be seized up, or the guide may be worn.

HOWEVER:

The chain tensioner is a ratchet mechanism.  As it nears the next ratchet position, the chain will run somewhat loose.  That seems a little too loose to me though.  My chain has never been that loose.

The varying tension is caused by the phasing of the camshafts.  Sometimes the cam ramps load the gears in one direction, sometimes in the other direction.
Title: Re: cam chain tension & clearance questions
Post by: malcman on March 02, 2009, 12:57:25 PM
Sounds good, I figured it wouldn't hurt to swap the tensioners from my parts bike and it seems the tensioner on my good motor was pretty seized, it would only go about halfway out compared to the one on my parts bike. Chain seems to be considerably tighter now, one less thing to deal with lol.
Title: Re: cam chain tension & clearance questions
Post by: GeeP on March 02, 2009, 01:28:56 PM
Good deal! :cheers: