'78 650 SR - Cam Shaft Install - Which Marks?

All you can do is line it up by your choice of teeth, so if you think moving the cams one tooth would be closer, do it, otherwise you are set correct as it's going to be. You can imagine that camchain was x" long when it was made new, now just like anything, it's slightly longer than x" from wear. The more wear the longer the chain gets, the tensioners take up the slack, but timing will still be off some. I'm sure you did it right.

As Ron said the difference is likely due to a stretched cam chain. When you say the tensioner is not tightened up, what do you mean? According to the factory manual the cam chain tensioner should be out when you line up the cams and count pins, keeping the chain tight up front. Once they are timed you tighten the cam caps down, install the top tensioner and then the cam chain tensioner last.

When I did my first shim adjustment on my 650 I was worried about the cam timing too. As I recall I did everything by the book and no matter how I did it the marks were a hair off, just like yours. One mark was down and the other up a bit, but if I moved the cam and tried different things the best I could get was what you are seeing now. I carefully buttoned everything up and slowly turned the engine by hand and all seemed good, then I fired it up and it ran great.

It's good you asked about it. It would be very obvious if the cams were off a tooth, the marks would be off more than a millimeter or two. You seem to understand the pin count process, I think you can trust that everything will spin free and not hit.

Thanks for the reassurance guys, really appreciate it. Helps to put me at ease.

OKC, when I said the tensioner was not tightened up, I meant I had the rear tensioner installed but was not set (i.e. locked) but just under the spring tension. When I setup the cams and counted the pins, both the top guide and rear tensioner were not installed.

Before reading your posts I just came in from doing it again (third time) with the same result. This, in combination with your reassurance, has me now believing it should be good. I've spun it many times and it seems good. I have a few more weeks of other work on the bike before I can fire it up though.

Question though, will this affect the ignition timing at all? Meaning, when I set the timing with a timing light, will this bit that its off affect this at all? Probably over thinking everything here, but it's my first time.

Thanks again.

The ignition is all on the crankshaft, so camchain has no effect on it. A couple years ago I said a camchain will last upwards of 100,000 miles, but they do stretch just like a drive chain and you may not be running 100% because cam timing will be off to a certain extent. I always was probably opposite of most guys where cosmetics is my thing, how great they run is secondary.

I was wondering about the lifespan of these chains. Thanks.