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Aaronbagby
02-10-2016, 10:26 PM
Long shot here, but I'm hoping to help a buddy. He has a 1993 Yamaha TDM 850. One day, he was riding it on the highway and his front sprocket popped off the bike. He claims that when he tried to reinstall the sprocket with a new nut (old one was lost on the highway), it would not go on past two turns because the thread on the mainshaft is damaged. They honestly don't look outright thrashed to me. Has anyone here ever been able to repair threads like this without pulling the transmission out? Thanks in advance.

6719167192

DustyDave
02-11-2016, 10:54 AM
I think those would fix with a thread file. If its too hard to cut with a thread file I have used a spare nut and valve lapping compound. It takes hours of small back and forth and forth!
Dusty

Aaronbagby
02-11-2016, 3:25 PM
I think those would fix with a thread file. If its too hard to cut with a thread file I have used a spare nut and valve lapping compound. It takes hours of small back and forth and forth!
Dusty

Thanks. I'll see what I can do with it!

farmall
02-11-2016, 3:52 PM
If you do cure the problem I'd slather it with red Locitite so it doesn't move after final nut installation. Loctite doesn't gall threads.

Shovel52
02-11-2016, 8:25 PM
You'll probably have to go buy a dye..

Aaronbagby
02-11-2016, 11:55 PM
If you do cure the problem I'd slather it with red Locitite so it doesn't move after final nut installation. Loctite doesn't gall threads.

That was absolutely the plan. Thanks.

Aaronbagby
02-11-2016, 11:56 PM
You'll probably have to go buy a dye..

This is what I originally thought, but I can't see a die working with the shaft on the motor. Wouldn't the surrounding parts block the die handles? Also, would using a die for the existing thread size even do anything?

Blackbetty
02-12-2016, 10:06 AM
It looks totally salvageable - I'd get a few nuts, lube the threads with motor oil, and try to run them down.

Shovel52
02-12-2016, 12:40 PM
Yes, a dye would work like a charm.,,once it started it would run on up...you would have to make some king of handle to screw it on, or vice grips even....and taper a little with a file... but it's far better than pulling the unit out..I've done it several times on other stuff.

Aaronbagby
02-12-2016, 12:50 PM
Yes, a dye would work like a charm.,,once it started it would run on up...you would have to make some king of handle to screw it on, or vice grips even....and taper a little with a file... but it's far better than pulling the unit out..I've done it several times on other stuff.

Can you explain how you mean to taper it with a file?