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I am reinstalling the drive shaft after changing the clutch on a 1979 R65. The four bolts that connect the drive shaft to the back of the transmission are new. They all went in finger tight just fine. I started tightning them one half turn each. One of them never got tight. I pulled it out and its threads were trashed. I replaced it with a used bolt which tightned up more than the first one, but it also felt like it was slipping so I stopped without leaning on it very hard.

I intend to finish the assembly so that I can test the clutch before I do anything about it, but I don't think I want to leave it this way.

So - whats the risk of having one semi-stripped drive shaft bolt. How do I fix it? Is the back plate on the transmission replaceable? Fixable? What have I gotten myself into?

Loctite 243 - oil resistant.
I wouldn't trust it forever.

So - whats the risk of having one semi-stripped drive shaft bolt.

The screw will back out and interfere with the moving parts in it's path ...

How do I fix it?

Tap threads in the plate of the next size, and source an appropriate screw.

Leaving those threads in that condition may work for a while, but you cannot really know for sure.

I would find a good used output flange and replace yours. It will require that the transmission be pulled out, a flange puller tool be used....and then back in the bike. It is not a difficult job. I was just wondering if it could be done in the bike, but I imagine that it would be more trouble than it is worth.

As for finding the output flange, I would check with guys that rebuild transmissions (like me) that usually have a stash of parts. I only do the 4 speeds....sorry. Oh, I just remembered that Rob has a transmission for his R65 that he ran without oil...if I remember correctly. Maybe he is willing to part with the output flange, as it should still be good.

[quote="vanzen@rockerboxer.comTap threads in the plate of the next size, and source an appropriate screw.[/quote]

Do I have to do two of them to maintain ballance?

I'm thinking you could do it w/ the tranny in the bike with a holder/puller like Cycleworks makes.

But, not worth the extra head ache to save the 1/2 hour to pull the transmission.

bbelk wrote:[quote="vanzen@rockerboxer.comTap threads in the plate of the next size, and source an appropriate screw.

Do I have to do two of them to maintain ballance?[/quote]

I would do all four if you go that route...to keep the heads consistent. I would make sure that you don't have to enlarge the holes in the driveshaft flange. Mcmaster-Carr sells 12 point head bolts....but only in standard threads.

http://www.mcmaster.com/#cap-screws/=ah3tr2

Here is a metric source:

http://www.allensfasteners.com/search_r ... aramCat=81

I hate to shoot down ideas...but the more I think about using a larger bolt in this situation, the more cons I can think of. The clearance in there is tight....and a larger bolt will require a larger wrench. A larger bolt may not fit through the driveshaft flange holes (I have one out of a bike if you want me to check). Since these are replaced every time you remove and install the bolts, you will have to keep a stash on hand or be sure they are available. The next owner will be thrown a curve ball.

It may still be the right path for you....just throwing out some thoughts.

I would HATE having to remember which of the 4 holes used the queer fastener.

I like the idea of replacing the flange.

I don't know how I could get mine off for you. I haven't the tools, nor a welder.

I would go with Frog on this and find a used output flange. Tis the only proper fix.

In the meantime if you NEED to ride the bike, I'd leave that bolt out, as long as the other three are perfect, and then be real gentle with it till it's fixed.

justoneoftheguys wrote:
I don't know how I could get mine off for you. I haven't the tools, nor a welder.

Just ship him the whole box, there is nothin good left inside anyway.