Woodruff key sheared off 81 KDX 175

[Bark3rd]

Hey all, I have a sheared woodruff key on the crankshaft, trying to figure out what to do. Has anyone had any luck with just somehow securing the flywheel in place without the woodruff key? Seems like this would be a whole lot easier than splitting the cases and replacing the crankshaft. So, how do you do this? Anyone in the Dallas area who works on these?

 

[dirt bike dave]

Unless the crank got damaed, there is no need to split the cases.

FWIW, I sheared a key on my '84. There was no damage at all to the crank, just the little key itself had literally sheared in two.

It was simply a matter of removing the flywheel and replacing the key.

BTW, don't put any lubricant on the crank shaft end - the flywheel should be a tight, friction fit.

 

[Bark3rd]

On this model, as far as I can tell, the key is actually part of the crankshaft, so theres no way to replace it without buying a new crankshaft

 

[dirt bike dave]

That's strange.

Typically, the key is a little piece that fits in a notch in the crankshaft and a matching notch in the flywheel.

I guess you could try machining a notch onto your crank to accept a key from a later KDX.

 

[Bark3rd]

Youre right, the key does come out, it was just ground down flush and looked like part of the shaft.

Unfortunately while re installing I managed to strip the internal threads in the crankshaft with my impact wrench (it was on low).

So...what now?

 

[julien_d]

Only option are to run a tap through there and put a larger bolt in, or you could try a helicoil or timesert.

 

[reepicheep]

Are the threads *in* the crankshaft? Or on the end of it?

 

[sr5bidder]

bark3rd
the threads may have been stripped allready by a PO, I have not looked but I take it there is a bolt that goes into the crank instead of a nut that goes on...I'm not shure there is room enough to drill it out and use repair kits but maybe you can study the bolt and find something slighty bigger with fine threads (maybe a fine US thread) and tap it out carefully (you wouldn't want the tap to snap off in there)

 

[reepicheep]

I tried the permatex repair kit for a really easy repair, and it was beyond useless. The glue never even set. Maybe it was out of date or contaminated, but it came right out of a sealed container fresh off the store shelf. No way I would trust the stuff on a crank (though I'll never touch it again for anything else either).

Heli coils are nice and strong, but do require a bigger hole.

An approach I have used before is to tap one size bigger, and see if that holds. If so, great. If not, then you have almost the right sized hole for the heli coil.

 

[Bark3rd]

Thanks all. I friend is sending me a couple of high quality longer bolts that will hopefully catch the remaining threads in there.

1 yr of ownership and still no ride!! lol, good thing I have a couple of KTMS laying around.