03 WR450 flywheel key, revisited....

5 replies to this topic
  • VB_Racing

Posted June 05, 2007 - 06:06 PM


I picked up another WR450, this is my 3rd WR, and my 2nd 450. I remember all the problems with the 03 WR's with the woodruff keys shearing, idler gear swaps, and so on..... Well I bought this WR with a non working starter for real cheap. I pulled the idler cover, and saw no problems with the idler, but the flywheel one way clutch spins both ways. I ordered parts and proceeded to kick start the bike for a couple months.
Yesterday I got around to replacing the clutch, pulled it apart and found that NONE of the fixes have been done to this bike. The flywheel had not been loctited and the idler is still the old style.(I should have known if I payed attention to the outer cover).It had never even had the jetting change made for easier starting.Sooo... I installed the new one way clutch and installed the flywheel with the correct torque procedure, and loctite,rejetted and ordered the torque limiting idler, cover and bushing.
BUT, then I got to thinking. this bike has 4 years of riding under it's belt with no issues until the one way wore out(It definately had no mechanical failure , just would not hold any more) and this thing is starting great.
So the question is, how many of you 03 WR owners actually switched over to the new parts, and if you didn't , has the starter been reliable??
I am still switching to the new style parts, but it just makes me wonder after this thing lasting as long as it has.



Posted June 05, 2007 - 08:48 PM


It's a roll of the dice. As long as the motor doesn't kick back during starting the '03 design will work. So if the jetting is right you may or may not have problems. The problem is if it does fail the bike will not run so you could end up stranded very far from home. IMO the upgrade is money well spent to avoid a lot of walking/towing.

  • bg10459

Posted June 06, 2007 - 05:55 AM


My bike never had any problems, and no indication that any dealer fixes had been done, but I did the '04 upgrade for peace of mind. And, FYI, the loctite and extra torque on the flywheel were "band-aid" attempts by Yamaha to correct the problem, which was actually just the poor starter clutch design.

IMO, the key to reliability of the starter (or starting) is in good jetting (and maybe a battery tender). My bike started perfectly all weekend.

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  • VB_Racing

Posted June 06, 2007 - 06:35 AM


Yeah, I have already ordered the updated parts, but I guess I am just surprised that this bike went 4 years without any of the "band aids" done including jetting, and it survived.
I wonder how wide spread the starter problem actually was??

I agree though that I will be installing the other parts for piece of mind, my luck is not as good as the previous owners.:thumbsup:

BUT, I would like to know how many guys out there have not done the fix, and how many hours they have on the old parts. I am starting to think it was a hit or miss issue.



Posted June 06, 2007 - 07:40 AM


Basically it was the combination of the starter design and the very lean jetting that came on the '03 bikes. I think if you cleaned up the jetting the problem would be greatly reduced. None the less the '04 design is much better.

  • ETP

Posted June 06, 2007 - 06:56 PM


My 03 Canadian model came stock with richer jetting than the US models. It sheared a key in 2004 (luckily in the garage) about the time the upgrade became available, so I did it.
I would have done it anyways because I don't like the idea of riding way into the back country knowing there is a design flaw.
Also, some the the guys had some more serious damage due to that starter clutch not being there. The key was the weak link in the chain. Locktite it, and something else will break. Like cases.:thumbsup: Suggest that you do the upgrade.


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