Power valve end play, side to side movement, rattle...

[Davehuge]

Hi all

I recently bought a well used 2004 EC300. The engine seems to be in good condition. It was running a bit rough but after adjusting the carb it's running sweet now.

My last remaining issue is a terrible rattle, it's very noticeable on overrun, for example rolling down a steep bank with the throttle shut.

I removed the left and right power valve covers and also the exhaust. The power valve seems to be well adjusted, it sits against the closed stop and has no slack in the mechanism.

I stuck my fingers up the exhaust port, I could feel a lot of side to side play/movement of the power valve. When I move it left/right I also hear the horrible rattle that I hear on overrun.

Questions:

1. Is there anyway to remove the sideways movement of the power valve (possibly with shims?) and thus reduce or eliminate the horrible rattle noise that I have?

2. Is it possible to remove the power valve unit without removing the cylinder head/barrel from the engine?

Thanks and best regards, Dave.