Flywheel removal

11 replies to this topic
  • yz400ed

Posted September 27, 2004 - 10:52 PM


I'm trying to change my timing chain on my '98 YZ400, so I need to remove my flywheel, I've bought the flywheel puller tool.

The first question is, are the threads of the flywheel nut reversed(counter clockwise to tighten)? I've read several threads in here saying that they are, and I've read many threads not mentioning it either, neither of the shop manuals I have mention nothing about it. So which is it, conventional or reversed threads?

Second, I know it's been asking in here before, what's the best way to hold the flywheel when torquing? I've read contradictary post about the Motion Pro clutch holding tool, some say it works, some say it just doesn't. Does it work on a YZ400 flywheel? What other ways is there to hold the flywheel?

Thanks for the help.

  • xeslaro

Posted September 28, 2004 - 01:47 AM


Yes the thread is reversed.
Not sure about torque-ing the nut as I just rattle mine up gently with an air gun thingy...

  • del_scorcho

Posted September 28, 2004 - 06:03 AM


What other ways is there to hold the flywheel?

You could put the bike in gear and have someone step on the rear brake. This will keep the rotor from turning while you torque it down to 40 ft.lbs. I used this same method when I was removing the rotor nut. Just keep in mind that even in gear the rotor will want to turn and will therefore spin the rear wheel. Thats why someone has to step hard on the rear brake. Worked great for me. :cry:

  • yz400ed

Posted September 28, 2004 - 09:18 AM


Damm, why doesn't either the factory or Clymer shop manual mention anything about the reverse thread? they should have a RED flag noting this. I've read several posting stating stripped or broken threads for this crank snout, and now I know why.

Thanks for the info

  • yz400ed

Posted September 28, 2004 - 10:15 AM


I don't mean to doubt you xeslaro, but can someone please verify that these threads are reversed. I just called Stealhy and Thumper Racing and they both said that it is a regular thread. I need to know this for sure, I don't want to wind-up with a screwed up crankshaft.

Totally confused :cry:

  • del_scorcho

Posted September 28, 2004 - 10:34 AM


The threads are NOT reversed on my 450. I used the Dr.D flywheel puller and it screwed in the conventional way. I can't imagine the 400's would be any different. If you can see the shaft then you can make out what type of threads your 400 has.

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  • Dano426

Posted September 28, 2004 - 10:55 AM


I believe my 426 had the standard threads.
The flywheel puller has reverse threads if that is what you are reading about?

Motion Pros Clutch Holding Tool
Here is a tool I used to hold the flywheel. The side with the two pins go into the two holes on the flywheel. Works great! :cry:

  • SXP

Posted September 28, 2004 - 07:37 PM


I've taken the flywheel off my 400 many times. It does NOT have reverse threads - you unscrew the nut counter-clockwise like all normal fasteners. The flywheel puller is also conventionally threaded (at least the one I use) .

  • slappie

Posted September 29, 2004 - 11:57 AM


I made a flywheel holding tool myself out of a couple of pieces of angle iron.

Just get a long piece (about 1 foot or so) and a shorter piece. Drill a hole in each so it will pivot into a Y shape. Bolt them together loosely. Then, take drill a small hole at each end of the Y, put a small bolt thru with 2 nuts on it and you're done.

Hold onto the lower portion of the Y, use the pivot to adjust them so the bolts at the ends of the Y fit in the holes on your flywheel. Make sure to set the bolts depth with the 2 nuts so that they won't go in deep enough to hit the stator. Works like a champ, even though my explanation probably is confusing.

  • Chipstien

Posted September 29, 2004 - 01:51 PM


Works like a champ, even though my explanation probably is confusing.

I'll say, can you post a pic. :cry:

  • xeslaro

Posted September 29, 2004 - 04:09 PM


Oops sorry. I was referring to the flywheel puller thread ( the female thread on the flywheel) The flywheel nut itself is normal. Once again sorry. Misread your post.... :cry:

  • yz400ed

Posted September 29, 2004 - 11:02 PM


Thanks everybody for all the info. I went out and purchased the Motion Pro clutch holding tool for my YZ400, it worked great. The nut is standard thread. I wonder why some people have stated that the holding tool doesn't work on the YZ450.

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