Torque ????? Help

I put a new weighted flywheel on and when tightening the nut I snapped the threaded portion of the crankshaft. Am I shafted? How difficult is it to replace? Any idea where I can get the parts? I am in an enduro this Sunday. I guess chances are slim I will be riding. Any help would be greatly appreciated. I used a torque wrench, but something went terribly wrong.



God Bless

Dave, Ive seen this posted before, Im not real sure what the guy had to do. You might look back at previous posts and try to find it. I think the torque setting is only like 34 ft/lbs, its not much at all.

Norman # 911


Oh my Lord, I’m afraid you are screwed. If that were me I’d probably still be breaking things, that really, really bites.

I wish I was wrong but I think you are going to need a new crank, I don’t see any other options given that you broke the end off. You may be able to save a few dollars through a crank rebuilder like Falicon, I don’t know if they do singles anymore but it is a place to start. They are press-fit crankshaft experts so you may want to call them regardless, they may know a better way to skin this cat.

I bought a new crank assembly (rod & bearing included, ready to install) for my ’00 for $300 from NCY, I think that may have been discounted though, it lists for $329. I couldn’t believe it but they had it in stock (800-225-1629).

As for replacing it, um, yeah, it is a fairly involved job, but I did it so I’m sure you can manage as well. The one invaluable trick I’d convey is the “tool” I made to remove the old one and install the new one. If you want just reply and I’ll describe it in detail. I was quoted like $300 for the tool the manual calls for, but you may want to check that because I only asked one parts guy, and he did seem confused by the weird PN for this tool given in the manual.

If you have a 400 you may consider getting a 426 crank, barrel and piston kit (two of the three you probably need anyway). The barrel is “only” $250 or so, and you will now have a 426 :)

Finally, I’d like to say that this really sucks, you may consider breaking some inconsequential object, that usually makes me feel better (unless someone is watching in which case I just feel stupid).

Originally posted by DaveJ:

The other option would be to drill and tap a bolt into it.

Hey, that’s a great idea. You’re right, a tapered shaft and woodruff key hold the flywheel on and timed correctly. You may need a machinist for this to make sure you get a straight, properly centered hole, in which case you may have to remove the crank anyway.

But I think you should call Falicon, I’d be willing to bet they’ve dealt with this problem before, but again you’re gonna have to remove it for them to work on it.

Hopefully you can get it fixed.

I would think that welding the tip back on is option as well. You'd have to find yourself someone who can do brain surgery type welding, but between that and a little reshaping it may be a way to get your bike in shape before the weekend.

The other option would be to drill and tap a bolt into it, but you'd have to go fairly deep to maintain the integrity of the hold, and that may cause complications.

In either event, 34 lbs of torque is not a whole lot of force. I would assume there is a taper fit and key that's really keeping it on.

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