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YZ-WR trans gears NOT interchangable!?...

8 posts in this topic

so, ive been planning a rebuild to put a WR 1st and 2nd gear into my YZ trans. I did the research on here, read a few posts on how it was possible to replace the 1st 2nd and 5th gears with WR gears.

so i call my dealer and he talks to the head mechanic who has tried this swap before... SUPRISE! presumably its all or nothing. he said that the dogs would not line up between YZ and WR gears.

anyone know what i can do? i have the cases split and dont know what im going to do. maybe a slighty shorter YZ400 1st and 2nd? i want a wider ratio trans.

are any gears interchangable?

any knowledge is greatly appreciated. :cry:

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just FYI...most mechanics at dealerships say the 450 cam WILL NOT work in 426's or 400's either...hmmm, that's kinda funny.

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What we don't know is what kind of bike you are working on, and of course, it makes a big difference. It sounds like you are talking about a YZ426, but I can't tell for sure. One thing that is generally true is that the first gear pinion is cut onto the mainshaft, so any change to that gear means a shaft change. Some of the rest may interchange, though.

On a 426, the cam and forks are the same parts on both bikes. They are not on the two 450s.

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just FYI...most mechanics at dealerships say the 450 cam WILL NOT work in 426's or 400's either...hmmm, that's kinda funny.
The YZ450 was laid out from scratch as a four speed, rather than just having 5th pulled out, so the internal layout is quite different. The space abandoned by fifth was used to increase the width of the gears and locking dogs slightly to improve strength. The cam was designed with only two shift forks, as opposed to the 3 a 5 speed requires, and the forks are different because of that.

The internal dimensions of both 450 cases are also slightly different.

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greyracer says -

"What we don't know is what kind of bike you are working on, and of course, it makes a big difference. It sounds like you are talking about a YZ426, but I can't tell for sure. One thing that is generally true is that the first gear pinion is cut onto the mainshaft, so any change to that gear means a shaft change. Some of the rest may interchange, though. "

oops... i forgot that i dont have a signature. :cry: i am indeed talking about a 2000 yz 426 and i was wanting to figure out what year WR's gears would work. my manual is for YZ400's, WR400's and the first year YZ426 (98-00). then there is a different manual for 01-02.

im thinking i should get either 2000 WR gears or 99 YZ400 gears. but, at around $200 for the 1st and 2nd gearsets, i dont want to find out they dont fit after i buy them.

ive read here that 426's can swap gears. i REALLY want the first 2 WR gears. i just want to feel a bit more certain that this will work... before i buy.:cry:

thanx for the help.

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Here's what you have to do is get every part number for the YZ trany Now get every part number from the WR Now see what number's are the same that's the stuff you don't have to get In my case on the 450 i had to buy everything ... here try this place for number's and price's http://www.bikebandit.com/partsbandit/and print it out and right down part number's it help's when you put it back together:thumbsup:

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Unless you can get a definitive answer from some as to whether the WR 1st & 2nd will work, you're going to need a dealer who will work with you a little. If you want the first 2 WR gears, you will need at least:

The WR mainshaft (1st gear pinion)

The WR 1st gear wheel

The WR 2nd gear pinion

The WR 2nd gear wheel

The next thing would be to take your 2 transmission shaft assemblies to the dealer and lay them out on the counter and compare them. You need to know if the gears from the YZ mainshaft fit into their respective places on the WR mainshaft, and that the sliding gears lock properly against the gears they are supposed to engage all the way across.

Remember, the cam and forks are the same in both these transmissions, so my guess is it will work, but I don't know absolutely one way or the other.

:cry:

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Here's what you have to do is get every part number for the YZ trany Now get every part number from the WR Now see what number's are the same that's the stuff you don't have to get :cry:

ok, ive basically given up on the WR gears since every gear is different. so i compared the 00YZ and the 99YZ transmissions. it seem to make the swap work i would need:

the main axle

1st gear wheel

2nd pinion and 2nd gear wheel

and the 3rd pinion gear (for some odd reason).

thats all thats different between the two setups. however, the one snag in my plan is the clutch - it seems that the 99 YZ400 and the 00 WR400 both use the same basket and hub, but the 00 YZ426 uses both a different basket and hub.

these different clutch parts would have to fit the different main shafts, right?

again, ive hit a wall. :cry:

the ratios are so similar that its almost not worth the hassle. :cry:

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