Wr gears in yz 250

[crowboy15]

Done the searches bottom line do I need the wr426 gears or the wr 450gears? Going to be put in a 09 yz 250 with eg 295 big bore.?

[adz_244]

426 are a deffinate fit i think some people tried the 450 gears but i dont know the outcome

[arnego2]

What I read here on the board was that you need some serious machine work to make it happen. Wrf426 fits perfect at least the 3-5 gear set-up my bikes has in its box.

[crowboy15]

Thanks guys I will use the 3-5gears. 1-2 in the yz are good for my riding.?

[CaptDan]

There are many parts in the WR450 trans that are common with the 400 & 426.

The last I've read is that WR 400/426/450 gearsets all work.

10/12/2011

I have some good news for all of you. I broke a tranny gear in January 2010 and replaced 3rd, 4th, and 5th with the WR450 gears as listed below. These part numbers match the numbers for the 2006 WR450 as listed by Number9.

3rd pinion 5TJ-17131-00-00

3rd Wheel 5TJ-17231-10-00

4th Pinion 5TJ-17141-10-00

4th Wheel 5TJ-17241-10-00

5th Pinion 5TJ-17151-00-00

5th Wheel 5BF-17251-00-00

I have put over 100 hrs on these gears with zero issues.?

https://www.thumpertalk.com/forum/showthread.php?p=10728690#post10728690

But there is this...

7/15/2011

I experimented with some transmission parts I had. YZF 450 gears from 06-08 are wider and although they fit on the YZ250 shafts they did not have sufficient clearance in the 2-stroke cases. The 450 gears have four gear dogs while the 250's only have three...

https://www.thumpertalk.com/forum/showthread.php?p=10507485#post10507485

Maybe it was the use of YZF and not WR gears that was a factor in motojason's results??

Good luck and keep us informed on what you do!

[crowboy15]

That was my concern the 4 gear dogs on the wr450 as the the wr426 have only three like the 250.?

[kenpowell]

The 2002 WR426 gears that I used have 4 dogs. I used 1st, 3rd,4th & 5th. This closed up the 2 to 3 gap. In my previous YZ285-WR I used all 5 WR426 gears and did not like the 2 to 3 gap. This combination is better.

[CaptDan]

That was my concern the 4 gear dogs on the wr450 as the the wr426 have only three like the 250.?

Okay, completely understandable.

But it's curious, as the 450 'box has lots of carryover 400/426 pieces.

The 2003 WR450 2nd gear, 3rd pinion & gear, 4th pinion & gear, and 5th pinion have different part numbers from the 400/426, but the drive axle, 1st gear, 2nd pinion, and 5th gear are the same.

And just for laughs, the graphics show 3-dog gears for both WR 'boxes.

But then in 2004, the drive axle, 1st gear, 2nd pinion, and 5th gears change.

More things change in '05 & '06, then in '07 the drive axle changes again... (whoo! it's hard to keep track of this stuff!) ...and the graphic shows 4-dog gears.

Suffice to say, there have been many running changes to the same basic layout. It may take a more serious investigation to really clear up the picture.

I'm not well-versed on transmissions, but on the 3-dog/4-dog issue, aren't the gearsets "paired", so that as long as you used matching gears & pinions there would never be a situation where a 4-dog gear would have to mesh with a 3-dog pinion? ?

[number9]

I just recently installed WR426 gears 1-5 in my 09 YZ. Really like it so far.

You only need some minor case clearance for the WR 1st gear to work. There is a thread in the sticky section that shows pics of the grinding needed. Like the OP it took me longer to tape the case off than it did the grinding.

....

[bikedude127]

Im running my second WR400 set (3-5) of gears in my 07 YZ/EG285.. What Ive found it the 2-3 gap is closer by adding the WR 3-5.. Its like having a 2a and 2b then 4th.. However, the 285 pulls the 3-4 gap with ease ?

[kenpowell]

The 2 -3 gap on my YZ285 with all 5 WR gears was to wide and 2nd gear was to low. My YZ265-WR uses 1st, 3rd,4th & 5th as I stated above. Much bettter gear spacing. !st gear is a 'granny low'. Most of my riding in 2nd and 3rd in semi-tight Arkansas trails that are full of rocks.

[bobbyward]

hard to believe you have rocks in arkansas .........................lol !

going to do the wr change over too, have them just waiting, did you ran your yz 2nd ?

couple places around white rock the lower low would not hurt anything ...............

[kenpowell]

Yes, I used the YZ 2nd gear and the WR426 1, 3, 4 & 5. This closes up the gap between 2nd & 3rd.