Motorcycle Repair: CL350K2 top end noise, camshaft lobes, camshaft timing

Question
Hi Bill,
I am rebuilding the top end because of a noise sounding like rocks in a coffee can. I have nos and used parts (cam and rocker arms camchain rollers etc. ) so far but now I have scoring on one of the upper con rods do you think this is giving me the noise?
Paul

Answer
Paul.... I may need clarification on "upper con rods" part. The connecting rods for the pistons are one piece and part of the crankshaft. Did you mean the upper end of the connecting rod, where the wristpin goes? If you can wiggle a new wristpin in the end of the rod, it will make some clicking noises under part-throttle conditions and rattle worse when the clearances are larger.

I suggest that you look at all the parts that came out to see what the possibilities are. Honda did change the upper cam tower housing and there were some issues with camshaft lobes hitting the housing. A flapping camchain due to lack of adjustment or broken tensioner will cause a lot of noise.

Camchain tensioner rollers that have started chunking the roller material can cause some noises.

Take a look at the spark advancer to see if the weights/springs are loose and flopping around.

If the camshaft timing was a tooth off, there could have been contact with valves and pistons.

When it goes back together you have to check for excessive camshaft side play. There are various sized shims to take up excessive slack. Assemble the cam tower with camshaft and bearing ends with the side gaskets in place and check the camshaft end play. Maximum end play is .012"
There are two different types of bolts for the camshaft sprocket assembly. Don't mix them up. One has a shoulder on it and goes into the hole with the recess.

Hope that helps some. I have a CD with lots of 350 info on it, if you get stuck.

Bill Silver
www.vintagehonda.com