I had a near disaster on the maiden voyage of the new to me M20. About 6 miles out on the ride, a terrible grinding sound from the primary chain case got me to the side of the road. After trucking her home and getting the outer chain case off, I discovered that 2 of the engine sprocket bolts had worked themselves out and got tangled in the chain and knocked the chain off the rear sprocket. I have since learned that those bolts were supposed to be safety wired (which they weren't). The bolts are unusable and I have been unable to find some nor do I know what size and thread pitch they are. Information on the size and vendor for these would be greatly appreciated. I also remember seeing a photo of the correct safety wiring of these bolts but I can't seem to find it.
Thanks in advance,
Regards,
Barry
Those are 5/16 Whitworth bolts (sets). If the heads are drilled through with a small hole, just go through each hole with tying wire and twist the ends together with a pair of pliers. Ron
Thanks everyone for replies. I had some 5/16 x 18 bolts that I cut down, and drilled a hole in the head. Made up a new gasket and installed the inner chaincase complete with safety wire. I think I’ Replace the clutch rollers while I have it apart. Don’t know why the parts book doesn’t specify bolt sizes but that’s the way it is. Thanks again.
Barry
