bob abell

I had trouble with my Montesa when new but the chain was tightening up after a big hit. Cleaned up the factory grease from the sides of the cams, washers and spacers and OK. (leave the threads lubed though) I also make sure the cams are oriented so that if they get hit with a rock they would turn in the loosening direction. Saves the chain and huge loads on the bearings. Mark the position of your cams next ride. If the chain loosens without the axle moving then maybe time for a new chain. By the way I found that the DID (non 0-ring) chain that I replaced the stock chain with, wore quite a bit faster then the OE chain. It was on the slightly worn sprockets though.

I don't know about the pj1 but we use no-toil and you need to let it sit after applying the filter oil so that the solvent can evaporate. If you're installing it right after oiling, there is more chance that the solvent + oil would be drawn into the airbox. Also make sure you squeeze out any excess oil.

According to my Haynes book: stroke 50mm for both bore 56mm for 125 and 66mm for 175 primary ratio 74/19 for both transmission ratios the same final drive 37/17 for 125 and 51/13 for 175 Only lists side clearances for rod, not diameters so I can't see if the sizes are the same.

Found it!