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dogerxf

5th gear weakness

6 posts in this topic

I have suffered the "5th gear won't engage" failure on my 05 WR450 that seems to be fairly common on WRs that have done lots of road running. My bike has done 12,000km - I suspect most of it on the road in 5th gear (I've only owned it for the last 2,000km or so). I'm getting it fixed (a couple of gears, a selector and a couple of bearings), but I'm wondering if a later model might have a more robust transmission for road work. For example, a lot of engine changes were made between 06 and 07 and I wonder whether upgrades to the transmission were included. Anyone have any thoughts/info on this?

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You'd be better off getting a rear wheel with a cush drive to isolate the transmission from the shocks/loads of the rear wheel

I believe you can also get rear sprockets with nylon bushings in the stud holes as a sort halfway house to a cush drive, which may help

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2008 has trans upgrades

Don't know if they are retro fittable.

There is already a Cush feature in the clutch....

Edited by Krannie

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'06-'11 WR450 (and possibly the '12 as well) are interchangeable, but not with the '03-'05.

In theory, there should be nothing about running in 5th for any length of time that would affect the longevity of the locking lugs on the 3rd/5th pinions (the two components that engage 5th). Even if they bash back and forth on themselves some, that shouldn't do too much to change the undercut angles of the lugs, nor round over the corners, the two of which are the principal causes of the problem. Sloppy and/or very frequent shifts into 5th are another matter, though, and it might be that bikes with a lot of road time just get more of that than dirt bikes do.

It would be interesting to see the wear on a high mileage road-ridden WR that hasn't started popping out of 5th yet to see what is developing.

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I have cush hub on my 07.. do it right the first time, save yourself headache down the road and set your bike up properly!

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