Mushroomed crank threads-Advice please

Hi all,

Well, doing a piston, set of rings and timing chain on a 01 wr.Today i managed to somehow mushroom the threads a bit on the crankshaft, taking off the flywheel. I used a 'universal puller" which was fine and set up decently. I read on this forum, some say dont tap the center bolt, and others say do tap the center bolt. Others say dont rely on cranking the center bolt to remove flywheel. Well, i tapped on the center bolt with a hammer with gentle to mild taps. Seems as though i have a "flare" now for the first few threads on the crank.Will a dies fix this up for me?.Are the threads soft or very hard? Is the thread a 10mm x 1.25?.. The flywheel finally came off by cranking the center bolt with an impact gun,,,, Nothing else worked for me.

Thanks in advance

You can use a die but may be easier to use a thread chaser or a thread file.

Thanks Swede- Im working on it; just have to verify the thread

I'm not saying this is the correct fix but I've had to deal with mushroomed bolts before and in far less ideal conditions, like out on a trail and ALL of the tools in another truck. Anyways we were able to use a flat file and file down the first few threads without screwing up the threads. Able to file it down just enough to get the nut started straight then able to screw the nut on with a wrench then back off and back on and that was good enough to straighten it all out

Hi Swede,, Yup, im with you on that fix(file)..I just bought a 10mm x 1.25 die, which i have verified to be the right thread.This should work for me, but wont be able to try until i drive 1 hr where my bike is located. Once i get passed those first few threads, im good to go. The nut does not have a huge task here as we all know how difficult it is to remove the flywheel!..Thanks,!

I'm sure you've done this before but a heads up if somebody does a search and ends up on this thread. When first starting the die on a mushroom head be absolutely sure that it is going on straight!! When you start the die it will most likely catch the first thread it sees and will want to go on cross threaded and a die's job is to cut threads so if it gets started crossed then its going to want to cut new "crossed" threads all the way down

hey all,

Sorry for the delay.. The die worked just wonderful for me!..No issues, and done in 2 minutes. Perhaps some machine shop experience in my college years helped a bit)

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