Cam chain replacement

CAMSHAFT_-_CHAIN.png


Which part is the stopper? If I had to take the engine apart, yes, I would replace all of it. If the tensioner is fully extended, it's time to replace the chain. In doing so, I'm not sure how well you can see the guides. If you can see them, a visual inspection should tell you whether the guides are serviceable or not. Have you found rubber bits on your screens?
 
when I replaced my guide I just replaced chain and chain tensioner too.
If You are going in You might as well. thats my opinion
Make sure the guide is centered in the tunnel too.
Welcome to the site.
 
Thank you for the replies. The guide stopper is part six in the diagram. And yes, there were bits of plastic in the screen when I took it out.
 
The rear guide (#9) usually holds up pretty well. It may have some grooves worn in it from the chain but like I said, they usually hold up well. The front guide (#6) is another story. That's probably about this engine's weakest "link". It's not that it's a bad part, it's just that they're all near 30 years old (or better) and are failing at a regular rate now. The rubber strip usually comes unglued from the aluminum base. Here's how I found mine, about 2/3 off .....

FrontGuide2.jpg


On my parts bike motor, the rubber strip had fallen right off and was sitting down on the crank.
 
I replaced my chain and front guide, the rubber had come off of the front guide. The rear guide looked perfectand the wear surface was bonded tightly so I reused it.
 
I have a couple of '81 motors apart on the bench, and wondered about whether the rear guide/tensioner pivot arm needed to be replaced. (Sorry for the mediocre focus in the photo.) The wear material appears to be still bonded on both, not cracked or missing chunks. The one on the left had a front guide worn to the metal, since replaced, and the lighter wear areas on the rear look to have aluminum particles embedded in the plastic, probably wiped off the chain after it harvested them from the front guide. The plastic on both still seems to have close to the original thickness. Given 5twins thought that they hold up pretty well, I wonder , how often do people replace the rear guide? I don't mind spending a bit to replace something that could be a problem, but if the test is that there's plenty of wear material left and it's bonded pretty well, I'll run what I've got.

As a side note, I'm thinking that with a proper oil level, the chain probably drags oil up from the sump so the rear guide is pretty well lubed which would tend to make it live longer.

John
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