u/AsparagusTime969

I have a Tomos where I hear some knocking while walking and at idle. It does not seem to make a problem while riding. Does anyone have any insight into what it could be? Sorry for the background noise.

I have an original cylinder head and piston for Tomos that is limited to 25 kph what would my options be for porting, experimenting and trying as I have never ported anything before. Porting the cylinder and even the piston