Lost 4th gear

10 replies to this topic
  • hillclimbguy

Posted October 23, 2008 - 08:18 PM


I need to split the cases on my WR. Its an 03, lost 4th gear. Kind of a stupid question, will a flywheel puller from a Honda CRF work on the Yamaha. I know two strokes use industry standard same puller for all or most. But didnt know on the thumpers. I should know this, but want to hear it from the experts.:lol:

  • matt4x4

Posted October 24, 2008 - 04:13 AM


I was able to pull mine (2000) with a normal harmonic balancer puller since it had the threaded holes in it - I did need thinner bolts with metric threads that I picked up at a hardware store.


Posted October 24, 2008 - 06:03 AM


No the Honda puller will not fit. You can use a harmonic balancer puller like Matt4x4 is suggesting and though it is not the method Yamaha recommends I have done it succesfully as well. If you decide to buy a puller made for the WR make sure it is for the '03. The '04 - present WR450 and the WR400/426 flywheels are different.

  • grayracer513

Posted October 24, 2008 - 06:04 AM


The CRF450 puller works on the '06+ YZ450, but the puller threads on a WR are somewhat larger, so it won't work.

  • timoyz1

Posted October 24, 2008 - 09:26 AM


Good luck on your quest. My tranny rebuild was loaded with B/S. I bought a puller that was listed for my bike, 07 WR450, and it was too small. I ended up getting a puller for a WRF that worked. Then found out that 3 of the 4 gears that I needed, were back ordered from Japan, which equalled a two week wait. I'm on the downhill side now though, cases are together, and I hope to finish up this weekend. TT T-Day is under 5 weeks away, so at least I will make that.:lol:

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  • grayracer513

Posted October 24, 2008 - 09:39 AM


The thread on an '03-'06 flywheel is M33x1.5 RH. See if that looks close.

  • hillclimbguy

Posted October 24, 2008 - 11:29 PM


Thanks for all your help. I may put this on the back burner till after Thanks Giving. If I do a rebuild then I dont go camping for Thanks Giving. That cant happen. I have to go camping. I may try to hook up with some of you for TT day.

  • chrispy1202

Posted October 30, 2008 - 02:50 AM


I had the dealer use a puller on my '03 flywheel and it was on so tight that it buggered the threads in the puller, as well as flaring the end of the crankshaft. I had to get the machine shop to build me a puller that threaded into the six bolt holes in the flywheel to get it off. I would suggest threading the nut back on before using the puller. Once the pull is threaded on and jacking bolt is tight against the end of the crankshaft(decent pressure), i would suggest taking a hammer and give the end of the bolt a smack. This tends to help freeing up frozen parts.

  • timoyz1

Posted October 30, 2008 - 05:30 AM


A heat gun to the flywheel will also free it up without having to smack it too hard. The way I just did mine was; 1)Nut on the crank end
2)Puller installed tight
3)Heat on the flywheel
4)Retighten puller
5)Small whack with hammer

  • grayracer513

Posted October 30, 2008 - 05:46 AM


The shock of a hammer strike on the end of the crank is the most effective single thing in releasing a stuck taper. The whole process is kind of a finesse thing. You want the puller tight, but not so tight that it distorts the threads on the crank. In striking with the hammer, just tapping a little is a waste of time. You need to smack it sharply, but not with such force that it will mushroom the crank end.

Another important thing is the use of the correct puller. Although some flywheels and such may also be drilled for common wheel pullers, or offer a good place to use a jaw type, these don't direct the pulling force in as focused a manner as the tool intended for the job. More than once I have seen flywheels stubbornly resist removal by wheel pullers, and then pop right off cooperatively when the right puller was used.

  • matt4x4

Posted October 31, 2008 - 04:16 AM


Haha - Hey Grey - that's because the "wrong" puller loosened it FIRST - you know - just like the stubborn lid on the mason jar - the person who finally gets it off NEVER gets the credit - the person who had it before always "loosened" is just enough!

I'm not usually an advocate of using hammers near precise mecahnical equipment, but in this case a Smack with a hammer IS the best - fastest - least frustrating method.


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