WR tranny in YZ? - revisited

several weeks ago, i was asking about a WR motor in a 03 YZ frame. it was suggested that i just put a WR tranny in the YZ motor. i looked up all the parts and was planning on doing so.

now, it was brought to my attention that the 03 may need extensive machining to accept the WR tranny. apparently, back in 03 or so, when Rob Tuluie was doing the supermoto thing, they were working on this and there were issues. does anyone have any info or find the thread(i looked, but came up empty).

Thanks, Chad.

If Rob is who I think he is, he was using the YZ426 transmission, not the WR450 unit. He wanted that one because of its closer ratio spacing, but it did require quite a bit of work, which he detailed in a post I still have at home.

However, the WR450 transmission is a straight up bolt-in if you have the complete unit (two shafts, 9 gears, 3 forks, and the shift cam). If you doubt this, send a PM to TT member "yzf450jack" and ask him. He's done one and loves it. I'm probably going to do the same thing, if I can ever get that far ahead.

I've done it. My 03 yz450 has 03 wr450 gears in it. It's a big parts order, but we can do it if you're interested. Where do you live? I'm a mechanic at a shop in Moscow, ID.

-Stephen

If Rob is who I think he is, he was using the YZ426 transmission, not the WR450 unit. He wanted that one because of its closer ratio spacing, but it did require quite a bit of work, which he detailed in a post I still have at home.

However, the WR450 transmission is a straight up bolt-in if you have the complete unit (two shafts, 9 gears, 3 forks, and the shift cam). If you doubt this, send a PM to TT member "yzf450jack" and ask him. He's done one and loves it. I'm probably going to do the same thing, if I can ever get that far ahead.

cool, you just made me very happy. i am basically looking to gain the overdrive of the 5th gear in the WR for roadracing my YZ.

What about a 2006 YZ tranny in a 2003-2005 WR???

Don E

No one knows that yet. We need an "intrepid adventurer".

Guys;

If you get the parts list together (especially for the 03) can you please, please, please post it and maybe sticky it for us to use as an upgrade. Maybe you guys who are master mechanics can conspire to write up a quick how to also?

Seeing that so many people drop 500+ bones on some silly exhaust pipes it would seem to me that this would be a far better upgrade.

Guys;

If you get the parts list together (especially for the 03) can you please, please, please post it ...

The '30-'06 WR 5 speed is a bolt-in swap, but the whole transmission is required:

As I see it, you will need: (Qty needed; part number; description; illustration item number)

From the transmission page at http://www.yamaha-motor.com/sport/parts/home.aspx ('05 WR450 5 Speed)

1- 5BE-17402-00-00 DRIVE AXLE ASSY (#13)

1- 5TJ-17411-10-00 AXLE, MAIN (12T) (#1)

1- 5TJ-17151-00-00 GEAR, 5TH PINION (25T) (#3)

2- 90201-253K0-00 WASHER, PLATE (T=1.0) (#4 & 18)

4- 93440-25084-00 CIRCLIP (#5 & 16)

1- 5TJ-17131-00-00 GEAR, 3RD PINION (16T) (#6)

2- 90209-21332-00 WASHER (#10 & 17)

1- 5TJ-17141-10-00 GEAR, 4TH PINION (20T) (#7)

1- 90387-2113G-00 COLLAR (#8)

1- 5BF-17121-00-00 GEAR, 2ND PINION (15T) (#9)

1- 5BF-17211-00-00 GEAR, 1ST WHEEL (29T) (#14)

1- 5BF-17251-00-00 GEAR, 5TH WHEEL (21T) (#15)

1- 5TJ-17231-10-00 GEAR, 3RD WHEEL (21T) (#19)

1- 5TJ-17241-10-00 GEAR, 4TH WHEEL (21T) (#21)

1- 93440-28062-00 CIRCLIP (#20)

1- 90209-26348-00 WASHER (#22)

1- 5TJ-17221-00-00 GEAR, 2ND WHEEL (26T) (#23)

From the Shift Cam Fork page

1- 5NL-18541-00-00 CAM, SHIFT (#1)

1- 5BE-18501-00-00 FORK, SHIFT 1 (#8)

1- 5BE-18502-10-00 FORK, SHIFT 2 (#9)

1- 5BE-18503-00-00 FORK, SHIFT 3 (#10)

Please comment on any inaccuracies of error or omission.

What about a 2006 YZ tranny in a 2003-2005 WR???

Don E

the 4spd gears are about 25% wider than the wr,they made the wr's gears smaller to fit 5 in the same space as 4(or made the 4 larger to fill the space of 5 ?) now if what i read is correct(that they made the 06 cases wider to accept 5 gears) they kept the gears large and added a 5th,which would stand to reason that they would not fit in a wr,but thats just conjecture :applause:

I would like to upgrade my 2002 YZ426 to a WR tranny this winter since Ive made it street legal. I could really use some more top speed. So can I buy the two shafts, 9 gears, 3 forks, and the shift cam from a 2002 WR and it will work?

A 426 is a different thing, since the YZ and WR both had 5 speeds. In that case, the shift cam and forks, and the output shaft are the same in both bikes, as is a lot of the small, incidental hardware. The mainshaft is different only because of the low gear pinion cut directly on the shaft. Compare the rest of the parts by browsing the catalog at: http://www.yamaha-motor.com/sport/parts/home.aspx

You don't need to sign up for anything, just click "proceed to the catalog"

Thanks :applause:

Thats an EXCELLENT link Grayracer! Everone who owns a Yamaha should save that link to their "favorites"

So here it is... YZ426-WR426 transmission swap:

#5BF-17411-10-00 Axle, Main

#5BF-17151-00-00 Gear, 5th Pinion

#5BF-17131-20-00 Gear, 3rd Pinion

#5BF-17141-20-00 Gear, 4th Pinion

#5BF-17121-00-00 Gear, 2nd Pinion

#5BF-17211-00-00 Gear, 1st Wheel

#5BF-17251-00-00 Gear, 5th Wheel

#5BF-17231-00-00 Gear, 3rd Wheel

#5BF-17241-00-00 Gear, 4th Wheel

#5BF-17221-00-00 Gear, 2nd Wheel

I ordered all the parts I need to do a WR trans swap into my YZ. I ordered everthing from mrcycles.com. Total to my doorstep came out to about $560. Well worth the investment as this can make you go MUCH faster than an exhaust of a similar price tag. I can't even use all the power thats there anyways, I don't need more. Parts should be here Friday or Monday, I hope. Not sure if anything is on back order or not. Anyways I will let you guys know how it goes when I get'er back into one piece.

what are the differences in gearing between the YZ and WR 426. i try looking for the ratios but couldnt find them. thanks for the help.

The ratios on a YZ426 are 1.846, 1.533, 1.278, 1.091, & 0.952.

Ratios for a WR426 are 2.417, 1.733, 1.313, 1.050, and 0.840.

Would the '01 be the same as the '02 swap? I have a YZ426 based quad, and was thinking the WR may be a little beefier, and the ratios may be a little better in an ATV chassis.. any tips will be appreciated.

'00 through '02 should all be the same. You can always double check the list online at the link in my other post.

I have an 03 yz450f that i put the wr trans in and it was the best thing i ever did to improve the race ability in a desert race and yes it was a direct fit with no problem of any kind. It allowed me to change my rear sprocket from a 49 to a 43 an i still have a great 1st gear and an amazing 5th gear bike was clocked at an impressive 100.3 mph (Not a stock motor.)

OK................................Hopefully this should be the last post on this stickicky!!! :bonk:

YES, you can put a WR(04-05) 5spd trans in a '03-'05 YZ450F.(WITH NO MODIFCATIONS TO ANYTHING) :thumbsup:

If you do desert or high speed applications, this is an excellent swap. :eek:

If you do not do any type of riding over 75+mph(SX&MX riding) than this is not a big deal. Honestly and personally I LOVE :thumbsup: the 4spd, but I run out of gear in the desert, so I made the swap.

I put a GPS unit set for TOP SPEED in my camelback and opened it up on asphault getting my bike up to 92.2 MPH before I HAD to let off(not even near the rev-limiter). I am using a 14/50 sprocket setup with a bone stock motor, so top speed is NOT an issue. I'm sure tapped out this engine could reach about 94-95MPH with my current gearing(yes the GPS I was using is accurate).

For about $650-$700 bones, this an excellent swap, but be honest and realistic with yourself. DO YOU NEED or WILL YOU BENEFIT from this swap? :bonk:

If anyone ever has any questions about this mod please ask, I am more than happy to help you out. It is really not that hard to do!!!

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