gilera runner speed/crank problem..help please

Hi,
Having just been for a little blast I noticed the bike seemed to have a deeper tone to it and didn't seem to be as quick or fast at the top end took engine casing of to check all was well and noticed tiny metal fragments and the usual dust from the belt. Then as I turned the crank I could see it was making contact with the engine casing in a couple of places as I turned the crank a complete rotation.!??..
Can anyone suggest why this is happening..I've just fitted a new belt and malossi variator to my 180 and she was running sweet...is it possible the crank for some reason has gone out of line causing the variator to touch the casing
Help please!
Cheers all

 

Yeah the spacer was fitted..looking at in more detail the arm is definitly out of line and I suspect I need a new crank which I am more than prepared to buy..gonna fit a new piston too..any feedback as to which manufacturer to use for the parts..or any other tips while the engine is in pieces?
Cheers
Russ