CL175 clicking noise???


New Member
Have a 73 CL175.
Its been running well recently. When I started it up this morning it took about 9 kicks to get going, would start, idle fine but when I gave it gas and the RPMs got to around 3000+ the engine starts making sort of a clicking noise - not a backfire "pop" noise, but more of an internal clicking sound. sounds like its coming from the left side.
Haven't made any changes to it recently.

My thought is maybe a timing issue? which is messing up the sparking?

Any input as to where I could start first would be much appreciated.

as a note, the PO told me that the bike tends to go through plugs. I was having issues before (taking MANY kicks to start, left piston not firing, etc.) and replaced the plugs a month ago and it has been great since.


Over 1,000 Posts
While you are doing valves, remove the points cover and try to wiggle the cam up and down and side to side. Those engines are pretty rock solid but cam bearings are just like a 350/360 design and can wear out/sieze.


New Member
Thanks a lot guys, much appreciated and I'll check all that out.

I've also been reading up on this clacking noise, sounds like it could also be my cam chain and tensioner. As the sound is an occasional "clack" - it makes me wonder if the chain is a little loose and slapping something when the RPMs go up.

While I'm doing what you suggested, I'm gonna adjust the tensioner as well.

If you have further input lemme know.


New Member
Turned out to be the cam chain. I tightened the tensioner a bit and the clack noise is gone.

I was too dumb to realize before my original post that its also misifiring. Idle is choppy and giving it throttle increases the choppiness. no backfire, just inconsistent firing

tried checking valve clearance but I can't get the tappet covers off to save my life..

possibly blew another spark plug? (in less than a month)

also got some gas from a 76 station i've never used before, the ride exactly before the problem. I have fuel filters and got premium but is bad gas a possibility?


Been Around the Block
Is your spark plug black?

I had a similar issue, where the bike wasn't starting reliably, choppy idle and would usually die after giving it throttle a couple times. Once the spark plug fouled (black) the bike started backfiring.

Main problem was the pilot jet, which wasn't screwed in properly, and the air screw. The fouling was caused by the extra fuel that was being run because of the loose pilot jet.


New Member
Good to know. ya, the spark plug tip is black. its a thin black film that wipes off easily, but ya its still black.
sounds like you had the same problem as I have now!

Do you happen to know the stock pilot jet setting? or should i just loosen them each like 1/4 turn - start it up and see how it does?

when i first got the bike it was running rich, so i lowered the needle jet (3rd notch), previous owner had it all the way up (5th notch). I thought this fixed it but as time passed, i see it hasn't.

but i like the idea of adjusting the pilot jet.


Been Around the Block
Hey, did you end up solving it? Sorry I missed your post.
I imagine my pilot jet settings would have been different to yours. Between one and a half to three turns out is ok.

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