Whilst riding recently I experienced a sudden loss of power and the wheels locking up. This was short lived after which there is now a bad knocking noise coming from what appears to be the engine. It sounded very much like the cam chain so I took the head cover off. All seems to be well with the chain in good condition and tight. The tensioner works well and all the valves seem to be doing the right stuff. Carb has been taken off and the path between the carb and the inlet valves is clean.

Poked around in the cylinder through the spark plug hole and all is OK. Plently of compression when pulling with the manual start.

It could be the bottom end but before attempting major sugery is there any other suggestions on what this might be? I am thinking maybe something to do with the primary clutch? The knocking is rev related and is noisy on idle. Note this is not tappet noise. I know that noise and this is much louder.

Any pointers appreciated.

Chris.

 

Pull the primary clutch off and start the engine to see if the noise is still there - this should isolate if it is clutch or engine...... Of course it could even be in the centrifugal clutch (which is behind the primary clutch rear cover) as well........