Sprocket nut locking "washer" blues

I'm in the process of changing the front sprocket on my 73 850 Commando.

I have the new sprocket on, but for the life of me I can't insert into it the screw that holds locking mechanism (small plate that keeps the nut from turning, and is itself secured by one screw - the one I can't get to go in 0 into the sprocket). The screw won't go in even without the locking plate, much less with it. Seems that it goes in on an angle, and the nut itself won't permit the screw to be tilted enough to engage the threads in the sprocket. I have a good ball-end allen wrench so that isn't the issue - it really seems to be the nut physically preventing the screw from tilting enough to go in.

Anybody run into this, or have any ideas?

Thanks - BrianK

The screw is usually a slotted dome head not a cap head, are you sure you've got the correct thread? The screw does go in at an angle relative to the sprocket face but it is square to the face it screws in to.(does that sound right?) Ball ended allen keys are handy but you cannot control the screw properly when trying to start the thread.

I would double check the thread, check the start of both threads and if necessary put a good start on the male thread, then use an ordinary allen key to stop the screw flopping about.

Hope this helps,

Cash

Thanks Cash. It is the right screw. But this just isn't working. Geometry of the new sprocket is off just enough.

Is there a "Plan B"? - tab washer? Red loctite? Other?

It is a pain in the ass at the best of times, as cash says it should be a slotted screw with a dome head, I'd suggest you get the correct screw, the head on the Cap screw may just be enough to render it mission impossible. You've got to get it right and locked up because you dont want to be pulling that primary side off at the side of a road somewhere.

Amen to that Gino.


Okay, I'll keep at it.

Thanks guys - BrianK

sprocket locking blues

As a last resort you could chuck up the nut in a lathe and cut a narrow chamferon the outer edge, just enough to allow the screw head to clear the nut and start in the threaded hole. Good luck. James.

I found exactly the same thing. Sprocket was sourced from ANIL.
I found there was enough meat in the "washer" outboard of the screw hole to use a round key file to elongate the hole slightly - then it went in OK.

Thanks all. I was able to grind down the head of a slotted screw and get it in - hadda grind it so far I didn't think it would hold the locking plate on by the time it would fit, but it does! It's in there with a little blue loctite and hopefully I won't be doing this job again for a while.


Thanks for all the helpful advice - couldn't have gotten there without it.

Cheers - BrianK