Cam Chain Rattle - which tensioner is this and is it missing a part?

Hi All,

So everything seems to be running great except for the rattle. So I get out my Clymer manual and it is a bit vague as to which tension adjuster was on the bike. I have an '81 650CSR. It looks like there is something missing from the adjuster as there is a threaded hole with nothing in it (highlighted in the pic with an arrow). So questions are..... Which adjuster is this? Is it missing a part? Should I try one of the APE adjusters from Z1?

Thanks in advance!
Dave.
:huh:

Pretty sure you're missing the bolt and the lock-nut there.
I wouldn't run that bike AGAIN until you get one in there.:ohmy:

Well,after looking,I see that it's not REALLY a locking nut,but here is what you're missing...

Dave, I don't know if 650 had this tensioner as stock, but I have a '91 Zephyr 750 and uses same tensioner. I have taken it apart when adjusting valves, and the bolt you are missing(92001) is a "stop" for the main plunger(13118A).

You see, the main plunger has a long slot, and the tip of the "stop" bolt goes in, preventing main plunger from overtraveling. Actually, I don't think the stop does much of anything once tensioner is installed. When you take the tensioner off the block, however, that bolt prevents the plunger from jumping away. The instructions tells you hold the plunger with your finger, and then take the "stop" bolt out, and now you can let the plunger out of the tensioner body easy.

I would try to find out if this is the tensioner for this bike. If it is, I would get the bolt and washer, and simply install them see if it seats well into the slot. If it doesn't, or rattle continues, I would consider taking the tensioner out and inspect it. This is very easy, but the problem is that the carbs have to come out and that's the real pain. But, also, consider that if it is missing this part, it could also conceivably be missing some other part inside, like the push rod(13116), or a spring.

In any case, I doubt that missing this bolt by itself is causing the problem. But first, I would try installing it back. It is no good having missing parts, even if it is just an stop. If not original tensioner, get one.