Swapping cogs


I've spent a bit of time today looking at the parts manuals for the wr450 and yz450 and I've worked out that the 2006-2009 yz450 all have the same transmission parts and the 2008-2012 wr450 all have the same transmission parts. The parts manuals also show the 2007 yz450 & wr450 have the same transmission parts which I find hard to believe. I was looking at UK manuals where specific and Europe where not on the Fowlers website here in the uk.

My question is, if I'm going to order 4th and 5th wheel and pinion gears from a wr450 to fit my YZ to give a wider spread of ratios, am I to order 2008-2012 gears?

Thanks for any help.

What year is your YZ?

What year is your YZ?

Sorry, that would help :)



Edited by Nick280

I guessed that, but I don't have that good  a record with guessing, so...



The gears you want would come from any '07-'10 WR450F.  Both gears from 4th and 5th (4 in all) are what you need.  What you will end up with is exactly what the 4 speed YZ450 had, plus the WR 5th gear on top.  Don't gear too tall with this setup, or the gap at 3-4 will be bigger than you like, and 5th will be unusable in the dirt for the most part.  I went one tooth bigger than stock on the rear with mine for desert racing and still has competitive speed for the lake beds. 

I worked out the axle shaft it the same on 07 to 10 on the WR but the main shaft is different. I'd guess because of electric start?

I'll buy 1 cog first for the main shaft and check first.

Thanks for your help Gray.

Edited by Nick280

The main shaft is different because low gear is different.  The 1st gear pinion (the driving member of the pair) is cut directly on the shaft.  The only reason you would need another main shaft is if you wanted a WR first gear, and as I read it, you don't.


I did this exact swap a couple of times.  All you need is the two gears in each of the two pairs for 4th and 5th.  Anything else would just be for things like bearings, if you think they need replacement. 

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