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WR tranny (1st gear case grinding)

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This is for shrubitup and everyone who wants to know how much to grind.

After installing the 1st gear and shaft, you lightly turn the gear to mark the case. I only had two places touching at first but...

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Once done, I tried the gear again and realized I had to do more.

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So I decided to do all the way around.

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Now, it spins totally free.

I removed 1mm or less, it took longer to prepare everything then to grind.

This is the dremel tip I used, it was like butter.

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Good luck !!!

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Thanks you blokes thanks to your research and work I've got a WR450 complete gearbox on it's way to me right now, to be installed as soon as I have a reason to split the cases.

BC

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I have this mod on my 04 engine. Excellent mod. Question I have a WR 426 gear set. Will the WR 450 gears work as well? For some reason I was under the impression that they wouldn't. Anyone know for sure?

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Wondering the same thing, maybe Projectcxr can be our test mule on this. It was my understanding the 450 gears are beefier.

Don't tell me that, Guinea pigs have limited lifespans......:ride:

Nah it should all good... I hope.

BC

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Good one. I was wondering how it was done.

I might do 1st and second next time I replace the crank.

Second gear ratio would not change for me as I have the 01 engine and the ratio is the same from what I recall.

Therefore I should end up with only a lower first gear.

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What I like the most about the WR's 1st gear is that even with a 15 teeth front sprocket, you still have a lower 1st then our stock YZ.

Now, if that :ride: snow can melt...

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What I liked about the full WR tranny was the increased versatility, the YZ has the type of power spread that lends itself to the wider gaps and easily pulls the higher 5th gear. Of course it obviously complements my style of riding in the woods, I'm not much for slam bang riding (ie:brake slide into the corner, shift down and come out sideways). And as I have said before it really helps in the nasty, rocky and steep places to get started again and have a lower 2nd so you can short shift to help out the ole gyro. I don't consider myself a motocrosser, but really didn't feel it hindered me when I do participate.

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mtdirtbag-

I have a 00 yz250 and I was thinking about putting a wr gear set in it , I was able to get it titled and did a lot of dual sport rides last year, but the gearing was less than ideal , (having a kdx200 pass you on a open road sucks)

Do you know how much MPH I will gain on top of 5th? also did you/have you swap/swapped the primary drive from the WR?

My bike-

00 YX250

stock bore wiseco rotating assembly and piston

e-line lighting stator

13/50 gears

everything else mostly stock - for the moment

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Judging from the pics, could the removal of material be more accurately done on a lathe? Or would the set-up be more work than it's worth?

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Judging from the pics, could the removal of material be more accurately done on a lathe? Or would the set-up be more work than it's worth?

It takes more time to tape everything up then to grind.

That stuff is really soft + what we have to remove is a very small amount.

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Nummbr 7, I can only guess what the top speed is. One, its been awhile and two you always think you're going 100mph when tapped out! My best guess would be in the 70's, I do know that I could stay with the KTM's that had 6 spds (for the most part) and in cross country races straight stretch two track made the butt cheeks clench.

CaptDan: as said the amount is so minute that you could do 10 before you where set-up.

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Nummbr 7, I can only guess what the top speed is. One, its been awhile and two you always think you're going 100mph when tapped out! My best guess would be in the 70's, I do know that I could stay with the KTM's that had 6 spds (for the most part) and in cross country races straight stretch two track made the butt cheeks clench.

I really don't mind the stock yz gearing in the woods, I guess what I would mainly be trying to gain is being able to cruise at 45-50mph and not be at 8000 rpms,( on my dyno with the 13/50 gears I only hit 60mph on the top of 5th).

From what I gather the WR gears have a lower 1st and 2nd so I guess I could swap to the WR gears then go way up in sprockets like 15/48 or something then end up with roughly the same first gear ratio as the YZ but maybe +25mph on top of 5th, should make a more reasonable cruise RPM

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I think your first move should be back to stock gearing or 14/51, much cheaper. I feel the 13 makes the bike to abrubt in the first two gears and actually makes it so that first is only good for just a few feet before you need to shift.

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I assume you need to change out the main axle in order to get the WR 1st pinion? As I understand, 1st pinion is machined into the shaft?

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What parts do you need from the wr tranny to do the full 1-5 swap?

I know you need the main shaft and drive axle (counter shaft).

Do you need the shift drum or what else?

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