180 drive pulley problem...again..please help!!!

Greetings,
I need some help and sound advice. When I started with my project the teeth had gone on the drive pulley so I replaced it and all seemed fine..now 1000 miles later and it has gone again..it looks like it was
rubbing against the inside of the casing..why would itdo this??? Need an air gun now to get the nut off which shouldn't be a problem..
I guessing as the teeth have worn this has created a bit of play and then it touched the casing..I can move it a couple of mm...I just don't know why this has happened...it only been 1k miles
Any help advice would be greatfully recieved..
Cheers
Russ

 

Just to update my last..having delved past the variator and the ramp it seems this to was well on the way to loosing its teeth as it had shifted a couple of mm onto the teeth of the crankshaft as was a little tricky to get off..so the ramp had jumped on to the spines of the crank and the finned plates teeth had also gone..you heard of the happening before or is this a new one..the only thing I could think of was locking up the rear and doing skids??
The spines on the shaft are in good order..
Cheers
Russ