yamaha yz450 06 and up wide ratio trans


55 replies to this topic
  • WR450F_RDR

Posted July 12, 2009 - 09:05 AM

#21

I just finished this mod on my 08 YZ450F. it is a little spendy but well worth it if you spend a lot of time in tight woods type riding. swapping the gears on the transmission was really easy. the only daunting task is tearing the motor down to split the case. i enjoy riding my bike a lot more now.

  • LumpyBoy

Posted July 13, 2009 - 06:56 PM

#22

If you are tearing it down and you want real lighting, might as well add the WR left end crank, FW, cover (w/freeze plug), CDI, wire harness. And maybe the starter will work too.

  • erickdj

Posted July 14, 2009 - 10:00 AM

#23

If you are tearing it down and you want real lighting, might as well add the WR left end crank, FW, cover (w/freeze plug), CDI, wire harness. And maybe the starter will work too.


That's just overkill, in terms of cost. Might as well sell the yz and buy a wr, and mod the wr to be a fire breather. I've modded my 07 wr to be a real monster, much cheaper and easier than doing the stuff listed above.

  • cowboyona426

Posted July 15, 2009 - 09:26 AM

#24

gray, have you done any trans gear swaps in your bike or just sprockets? I would like to swap some trans parts someday but I doubt I'll ever get that far. I do think I need to re-gear though, the stock gearing is just a tad too high for the tight stuff, even with the off-road GYT-R flywheel weight installed. I still have clutch issues to sort out too which don't help me much either...

  • grayracer513

Posted July 15, 2009 - 09:38 AM

#25

My current gearing is 13/48. I don't ride that much really tight stuff, but they do like to toss some into the D38 races.

At some point, I'm going to want to either add the WR trans and figure out something for lighting, or build a WR into my desert bike. Two bikes seems like a good option, but not in the near future.

  • Jim813

Posted February 13, 2010 - 12:11 AM

#26

Do the WR gears have to be from an 07-up WR450f for the transmission swap to work?

Has anyone just put in a few of the gears from a WR (ex: 1st, 2nd, and 5th) instead of the whole tranny?

  • grayracer513

Posted February 13, 2010 - 09:52 AM

#27

Do the WR gears have to be from an 07-up WR450f for the transmission swap to work?

Yes. The earlier models use a narrower trans.

Has anyone just put in a few of the gears from a WR (ex: 1st, 2nd, and 5th) instead of the whole tranny?

http://www.thumperta...882#post7702882

  • Jim813

Posted February 13, 2010 - 07:53 PM

#28

Yes. The earlier models use a narrower trans.


http://www.thumperta...882#post7702882


Thanks for the link.
Does anyone have any feedback after only installing part of the WR transmission ( such as 1st, 2nd, and 5th)?

  • Polar_Bus

Posted February 14, 2010 - 09:19 AM

#29

Keep in mind for those of you contemplating swapping to a WR tranny. When you spread the gear ratios out you are going to experience more rpm's drop when shifting gears. This may, or may not be an issue depending on what your intent is. I owned a WR250F, and this exact situation was very frustrating attempting to aggressively shift my WR. The 250F's, it was difficult for the engine to maintain peak rpm's. I would guess the rpm drop will be less noticable on the 450's simply due to more abundant torque and hp. I can understand riders wanting a taller 1st gear , but i'm not really seeing why someone would need more speed (a YZ already will pull about 80+ mph ). But this is just my $.02...

  • hillclimbguy

Posted February 14, 2010 - 09:48 AM

#30

I've been tossing this around for a while now. I like the tight stuff and currently have a 53 13 on my 06 YZ450. Great for the stuff I do, but not great for riding fire roads, though I dont do the fire roads very often. Sure be nice of a six speed was available.

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • grayracer513

Posted February 14, 2010 - 10:34 AM

#31

Keep in mind for those of you contemplating swapping to a WR tranny. When you spread the gear ratios out you are going to experience more rpm's drop when shifting gears. This may, or may not be an issue depending on what your intent is. ... I can understand riders wanting a taller 1st gear , but i'm not really seeing why someone would need more speed (a YZ already will pull about 80+ mph ).

Desert racing is one reason you'd want the speed. Not so much for the top speed, necessarily, although every once in a while a lake bed gets thrown in. It's more a matter of cruising speed. In a typical race, I spend probably 50% of my time in 5th gear at one speed or other, and it would really be much nicer to run 55 mph at 6000 than at 7000 rpm. Better for the engine, too. It'd be nice not to have to flog the clutch so hard in the canyons, too.

as to the rpm drop, there's about 1000 rpm between the top 4 gears in a YZ trans at 9000 rpm, and about 1500 in a WR. I don't see that as a problem

  • Polar_Bus

Posted February 14, 2010 - 01:22 PM

#32

Can a WR450 pull peak rpms in 5th ? What are people seeing for real world top speeds on the WR's ?

  • grayracer513

Posted February 14, 2010 - 03:12 PM

#33

Can a WR450 pull peak rpms in 5th ? What are people seeing for real world top speeds on the WR's ?

No, I'm certain they can't. Check over in the WR forum regarding observed top speeds.

On paper, if the bike is capable of pulling to 10,500 with stock gearing (13/50), the '07 WR would hit 98 mph, not allowing for the inevitable losses to tire slip (even on pavement). At the rev limit, it would be 107.

  • WouldsAssassin

Posted September 02, 2012 - 04:07 PM

#34

I've read through quite a few threads on transmission swaps and it is established that it is doable up to the 09 model year. I can't find anything for the 10 and up YZ/WR transmission swaps.

Does anybody know it the '10+ transmissions are interchangeable?

Cheers

Edited by PilotHonda, September 02, 2012 - 04:07 PM.


  • grayracer513

Posted September 02, 2012 - 06:42 PM

#35

Snoop through the parts catalog and do a thorough search of this forum. Most of the part numbers are the same, but there are a couple differences.

As I recall, there was a post within the last year about someone who had attempted Either a complete or partial swap of an '07-'11 WR trans into a '10 and had some problems with it.

  • WouldsAssassin

Posted September 02, 2012 - 08:12 PM

#36

Snoop through the parts catalog and do a thorough search of this forum. Most of the part numbers are the same, but there are a couple differences.

As I recall, there was a post within the last year about someone who had attempted Either a complete or partial swap of an '07-'11 WR trans into a '10 and had some problems with it.


Yup a quick compare has most of the parts for 09 and 11 YZ450F transmissions as the same but with a few differences. The differences are in the first three alphanumeric characters in the part numbers and it's in the middle gears (Gear tooth numbers are all the same for all gears). I don't know what that means in the Yamaha database of parts designations.

If there was any concern the 09 and 12 WR450F transmissions are identical.

I found a thread pertaining to '10+ YZ450F 4th and 5th gear swap, but it fizzled out with having to purchase a new 5th gear.

Edited by PilotHonda, September 02, 2012 - 08:22 PM.


  • grayracer513

Posted September 03, 2012 - 08:28 AM

#37

I think that was the one I was thinking of. I was hoping to hear back from the OP, but he never followed up.

Yamaha uses a basic number parts system. The 5 digit number in the middle is what the part is, like a third gear pinion, or a piston ring, or whatever. The first three tell what it was made for, and the following two pairs of characters are revisions, alternate sizes, etc.

  • Gink

Posted December 16, 2014 - 08:05 PM

#38

I know this is an old post but thinking to modify my yz450f 07 to wr450 tranny. Any ideas where to pick up a deal on parts. Is it worth replacing bearing same time.

  • 700rScott

Posted December 24, 2014 - 07:56 AM

#39

I know this is an old post but thinking to modify my yz450f 07 to wr450 tranny. Any ideas where to pick up a deal on parts. Is it worth replacing bearing same time.

 

This on my to do list too and I think it would be worth replacing the bearing since you're already right there, why not?



  • n16ht5

Posted December 25, 2014 - 08:20 AM

#40

I got my parts on partzilla. I checked my bearings but they were all good, just put new seals in.

I only swapped 1st and 5th and it is nice to have the close ratio 2-4th gears while being able to kick it into 5th for top end.







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