Hey all, I am a newbie...
I just bought an old yamaha moto 4 with the 4 stoke 200cc engine. There is an erratic knocking at the bottom of the engine / trans close to the starter. It seems to start after just a few seconds of running and disapears when the engine accelerates or is under load. I can hear the engine hesitate on the harder hits. I don't want to keep running it this way of course, if anyone knows what this is and if there is a simple fix, I would sure apprieciate a reply. I've done alot of auto-mechanic work, as well as small engine work.

I did noticed what looks like an adjustment screw with Increase and decrease printed above it. does anyone know what this is for? The bike is shaft drive, if that helps.

Thanks all in advance. [img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-shocked.gif[/img][img]i/expressions/face-icon-small-frown.gif[/img]

 

It is 1986-87

 

My 225 dose the same thing. Its normal im pritty sure. and the increase/ decrease screw is for the clutch and when it fully engages, so dont mess with that.

 

I had an 89 moto 4. mine made some noise to for a few years until i sold it and is still running. sorry cant really help to much without being there in person. to actually hear the noise