FRONT SPROCKET

[jcslocum]

I wonder if you get tooooo much movement (still only have one thickness of sprocket spline ) between all those plates that causes the bolts to unscrew/break wires.

I was figuring since the bike is nearly 100% ridden in the mountains, maybe all the back-and-forth between acceleration and deceleration was acting like an impact wrench. I was a little miffed when the bolts came loose after applying Locktite on them, but I was completely shocked when the bolts came loose with Locktite AND the safety wire broke.

If you look at what you created it's not hard to see why it broke out. The sprocket was transferring all of the load to the bolts. It doesn't fit tight on the shaft so there has to be movement. All the keeper does it prevent side to side movement. Everytime you whacked the throttle you were wrenching the crap out of it.

[Desmo_Demon]

If you look at what you created it's not hard to see why it broke out. The sprocket was transferring all of the load to the bolts. It doesn't fit tight on the shaft so there has to be movement. All the keeper does it prevent side to side movement. Everytime you whacked the throttle you were wrenching the crap out of it.

Exactly.

I have been thinking of a way to leave the assembly a little loose so it has the freedom to allow play between the splines (in the direction of the force - along the path of chain travel). My only concern is the sprocket traveling in and out along the shaft, possibly further chewing up the splines and prematurely wearing the retainer. I may go back to that design and try to figure out the best way to allow some wiggle. The easiest way is to get a bolt that is a little too long and bottom it out in the shaft, but I hate bottoming out any bolt in a blind hole (usually boogers up the threads on both the bolt and the threaded part it is screwed into).

[ducinthebay]

I was thinking about this and came to the same conclusion. If there is any freeplay in the sprocket to the shaft, it will loosen up the bolt. the sprocket has to have freeplay, otherwise you will need to press fit the sprocket on the shaft.

Your best bet would be a shoulder bolt and use a warpy (Bellville) washer to reduce the amount of freeplay. Let the shoulder of the bolt bottom on the end of the shaft. Another method would be to make a collar that the bolt tightens down on, but does not transmit the torque to the plate. Use Loctite on the bolt threads, and a touch of grease on the bellville.

The Ducati manual suggests a thick grease on the shaft splines before you install the sprocket. As I think of this, Disc Brake Quieting grease would probably be the ideal stuff to put there. Its super thick, doesn't wander, and has a damping affect.

Cheers,