NGWClub®, Inc.

I already asked this here but maybe it will get a reply if I start a separate thread:
A while ago the bolt that attaches my '79 engine's flywheel/rotor to the alternator shaft backed out, broke through the cap and jammed, stalling the engine. I finally have the engine out and apart and the threads on the bolt and inside the shaft are messed up so I want to replace them. I should be able to simply transplant the entire alternator shaft assembly, complete with mounting plate from my dead '77 engine.

The alternator shaft assembly from the '77 engine came out easily; I just undid the mounting plate's bolts and lifted it out.

I can't get the one out of the '79 engine. I have all 6 bolts out and I can move the plate around; It sort of pivots a degree or so on the dowel pin and I can see space between the plate and the block when I pull on it but it feels like it is fouling on something inside the block so I don't want to force it and break something.

Anyone have any ideas on what could be keeping it from just lifting out like the other one did?

No real solid information but there were a couple of changes to the cases back in that area and that might be the issue. I forget exactly when but think it was mid to late in the 77 run that they thickened the case back there and added the primary tensioner?

I got rid of all my spare engines that were already split or I would go look. I think what I would do is put up parts break down images of a 75 and a 79 side by side on your screen and see if anything else changed. Maybe those dampers or something else have an impact?

I've been through the parts drawings and can't see anything different.

I also found the part in the '80-81 1100 FSM about removing it and it says to remove the bolts and "slide the generator drive assembly free of the case". So unless they changed something between '77 and '79 and then changed it back before '80 it should just lift out.

Looking inside the hole where the assembly came out of the '77 and putting the assembly back in & removing it again I can't see anything even close to interfering with it coming out.

Tomorrow I'll try rotating the engine to see if something falls out of the way and stops fouling it.

Sorry Bob I have nothing to add either. both my 84's just slid out too.

I've never been in the back side of the motor, so I'm just going by parts diagrams... how much of that assembly is inside? Looks to me like most of it is, so, here's my half a cent's worth... Could be that the alternator bolt coming loose is only half the problem. As all those gears and stuff are tied into the crankshaft, something giving way inside is quite possible. I'm betting on the damper(s) being mucked up, and causing the shaft to bind... but that's just a WAG...

I finally gave up and decided to pry up on the plate and see if it moved. It came out reluctantly and now I know why it didn't want to come out. The gear has uniform dimples about 3mm across next to the root of each tooth and the gear on the crank that it meshes with has uniform matching bumps. It looks as if something bounced around between the gears at some time during the long history of this engine (it has already been in 3 frames and survived 2 write offs).

This would be a fairly easy thing to fix if I was to split the blocks on both engines and swap in the good gear from the '77. But that will have to wait; for now I'm going to close both engines back up, box the parts I removed to get this far and go back to getting the 1100 engine ready to install and the bike ready to install the engine in it (I need to do a lot of rust removal & painting while the engine is out).