QuestionHey on my 1984 Honda CB650SC there is a rattle that sounds like it's coming from the top end. I took the cams out and tried to inspect the slippers, the one attached to the adjuster has less than a millimeter worn into it and the other isn't worn at all. The chain looks good but I think it's the original, my bike has about 22k miles on it. Could the chain be stretched and wearing into the slipper?
AnswerHello Torry,
The top end of the CB650SC is a little noisy
at least when cold. This is due to it having
hydraulic valve lash adjusters. These are
similar to what most automobiles use
and I am sure you have heard that noise before.
Only replacing the adjusters will help there.
If the noise is a rattle noise then it could
be the cam chain is loose.
This can be due to a weak cam chain tensioner spring
or cam chain and slipper guide wear.
These could be close to needing replacement
at 20k to 30k miles.
You can rotate the engine slightly forward
and check the chain tension but if it is adjusted
correctly and the tensioner is working ok the noise
will be less.
The guide below should have info on the
cam chain tensioner.
There is also a small chain on the alternator drive
that might rattle but only a chain replacement will help
there as well.
Here is a guide with some useful information:
http://home.online.no/~ivbekkel/CB650/Honda%20Cb650%20Simple%20Service.pdf
http://webservices.motorsportdealers.com/parts/partImages/HOM/2/14ME5D/ILLUST/E1...
Wayne S.
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