Strange ticking/sucking/tapping noise

[nulldevice]

It's a difficult noise to describe. It is there at idle and it goes away at mid to top engine loads and speeds and comes back when it slows down to near idle.

I thought it was a leaking exhaust, but a disassembly and reassembly with new gaskets at the exhaust port and muffler inlet and needed new muffler made no difference.

I thought it might be (shudder) the rod knocking, but the noise doesn't seem to happen when a rod knock should, and I really don't think it is piston slap.

I checked the variator and driven clutch/pulley when I replaced the belt today. All was good after a thorough clean and lube, but that made no difference. It does work much smoother now though.

Valve lash? That's tomorrow's check. But the noise goes away at higher than high idle speeds and it runs too well for me to think that is it.

I'm using Mobile 1 10w-40 high mileage oil.

Any ideas for my SunL 250 with a Honda copy motor?

[skuttadawg]

Roller weights rattle around and make a noise like a bad bearing can make . Get a stethoscope and listen to it on the CS and see where the noise is emitting from

[nulldevice]

I finally chaced down the noise source. The rattle jingle was loose tools. The knocking sound was the carb hitting a
The frame. The hissing was the carb at the manifold.

All cured by tightening one little screw.

[justdon]

Lucky you thank god thats all it was..