Opinions, please: should I put loc-tight on the threads holding the engine sprocket nut? There's no mention of it in the shop manual, and the threads are oriented to tighten as the engine pulls. BUT, there was some type of goop on there when I changed the sprocket... Is it sufficient to torque to the recommended point? Thanks! --Cliff GSF600S ('03) "Bounce" GL650 ('83) "Eunice"
Yup. Bimota for one. The problem is that it's difficult and expensive to have the countershaft and swingarm pivot on the same axis. You'd have to either have a very robust bearing on the opposite side of the engine as the countershaft, or you'd have to have two bearings - one on the opposite side of the engine, one on a solid shell surrounding the countershaft. Having a co-axial pivot will also probably make a bike wider, although this can be solved with a short shaft driving the rear sprocket geared to the countershaft. In addition, having the pivot be somewhat above the countershaft introduces a small amount of "jacking" into the suspension, which counters the natural tendency of the bike's rear to squat on acceleration - the chain "pulls down" the swingarm. If you want to have the pivot and countershaft sprocket be co-axial, probably the best way to do it would be to have two parallel swingarms, one above the countershaft, one below, and have the "virtual pivot" be at the same place as the countershaft. (Basically like a BMW Paralever suspension.) The problem with this design is that it requires *4* pivot points rather than just one, like a conventional suspension - although you might be able to get rid of one pivot by using a fiberglass leaf spring in place of one of the suspension arms - this will make wheel location poorer, though. -Andrew
I had the same problem on my XT600, only there is no safety bolt on that bike. However, after I started using blue Loktite on the sprocket nut it has stayed in place. Guess I'd better have a look on the TT600R to see how things are, probably not too good as previous owners seem to have been mechanically inept (to be polite).
