Honda305.com Forum

My newly rebuilt 160 suddenly has a high pitched chirp at idle.

Doesn't seem to increase under power, but I have loud pipes, so maybe I can't hear it.

I did confirm oil flow after the rebuild, and have driven about 75 miles without trouble since the rebuild.

Anyone seen this before? I don't like the sound of it.

Well, that that has to rival the geico pig snorting wheee! while driving- maybe you have a couple of captive chipmunks out for a joy ride!
Do you think the noise is mechanically related ( perhaps cam chain slap ) or it be chuffing from an air leak like an old VW air cooled exhaust?
Does the chirp happen while accelerating or when you close the throttle, or both?
Allan

No hitchhiking animals I can see. Having read up, I am hoping its exhaust or cam chain. the chain is brand new. The other candidates are cam or bearings, and I don't like the sound of that.

Try this- so cover end of 1 pipe at a time with a rag and you may hear a leak as you open the throttle slowly (on center stand in neutral) then check the other.
If you think bearings or mechanical you'll have to drop the motor.
I'm assuming that you adjusted the cam chain tensioner.
Allan

Thanks. I will try that. Ad tighten the pipes generally too.

I did the cam adjustment when I assembled the top end. It's a new cam chain, so maybe it needs an adjustment now that its broken in.

Happy New Year everyone. The chirping 160 is still singing.

Here is the video: http://youtu.be/yoQjHboSRyk

I have adjusted the cam chain tensioner, and the pipes, and used a scope to listen all around the bike.

I cannot tell where this chirp lives!

I did confirm one thing - it chirps when the kicker rotates the engine, even when not running, so that rules out exhaust I think.

Doesn't seem any louder on right, top, or bottom, and is not constant. It comes and goes, but is definitely getting worse.

Compression is 150 in one side, and 130 in the other. The 130 is oddly low, as it was 150 a few months back when I did the rebuild. Could a broken ring chirp?

Any ideas or wisdom before I pull the engine?

The bike also refuses to idle for more than a few minutes before fouling the plugs, which is fun. Runs like a monster at above 1/4 idle. Would make a good track bike maybe....

Did you have this engine running before the rebuild?


HT