YZ450F vs FX vs WR

[Kurlon]

This came up in conversation at the track: E-Start on a sumo would be awesome.

Well, it looks like Yamaha has come up with such an option. Take a YZ450F, add a WR transmission and e-start, 18" rear wheel, 15lbs later job done. If you go WR you get an EPA approved tank, spark arrester baffle based exhaust and lights for an additional weight penalty. You can actually add e-start to the F as it's the same cases, but you'd need to swap cranks... might be easier to just swap an F transmission into the FX if that's what you want?

Thoughts?

[Pigman]

Cams and exhaust are a tad more restricted...also

Love my WR.........

[union]

You can buy a KTM. Mine was electric start.

[csmutty]

Cams and exhaust are a tad more restricted...also

Love my WR.........

Wrong...

[Pigman]

Wrong...

Ummmmmm I am 100% sure for 2004 WR450 vs YZ was the cams and exhaust...trans also has a wider gear ratio. Kick stand, stator ect but they are the same

look it up people do the swaps all the time bud........ SO SUCK A DICK

[nhbubba]

[Kurlon]

Ummmmmm I am 100% sure for 2004 WR450 vs YZ was the cams and exhaust...trans also has a wider gear ratio. Kick stand, stator ect but they are the same

look it up people do the swaps all the time bud........ SO SUCK A DICK

We're talking about the current gen, 2016/17. Looks like they share cam timing between all three models, but lift is different.

[csmutty]

Ummmmmm I am 100% sure for 2004 WR450 vs YZ was the cams and exhaust...trans also has a wider gear ratio. Kick stand, stator ect but they are the same

look it up people do the swaps all the time bud........ SO SUCK A DICK

If you have a 04 YZ450FX that you have worked on...please let me know

[Kurlon]

So, looks like the F, FX and WR share a good chunk of chassis bits.

Front hubs / spacers /etc are the same between the F and FX. The WR is slightly different due to the speedo drive. Yamaha changed axle diameters up front in 2014, going from 20mm to 22mm. You'll need 2014+ sumo wheels, or new spacers to run older ones. Brake rotor offsets have stayed the same, the brake lug pattern matches YZ450Fs back to 2008, so sumo brake kits are all over the market.

In back, the FX and WR are using the 2008 and prior YZ450 hub, aka what's on the current YZ250s. Smaller axle as a result. So you'll need a 2008 YZ450F compatible sumo wheel for them. For the F a 2009 setup should drop right in. Now, interestingly they're using the same swingarm on both bikes. This means the FX / WR should be able to run 2009+ rear wheel setups if you get a F axle, nut and axle blocks. On the YZ250 Yamaha continues to use an older, heavier swingarm to support that hub, and many update to a newer 450 unit for better geometry and a weight savings, it's interesting to see how Yamaha opted to deal with it on the FX and WR. Why they didn't just lace an 18" rim to the same hub as the F and call it good I've no idea other than wanting to use the same whole assembly as they shove on the YZ250?

The F vs FX / WR use different clamp sets, likely different offsets. Steering stem bearings match YZs for the ages, but I don't have confirmation on stem lengths yet. I'm betting it's the same 'long' stem they've used on YZ450s for years now. So an older YZ450 front end should chuck right on. AFAIK the steering stop system hasn't changed since they went aluminum frames so no worries there. RSW racing lists 2009 to 2016 as all being supported by the same clamp setup so... swaps should be easy.

[tls25rs]

So would the YZ450F transmission or the YZ450FX transmission be better for the Supermoto application? I get the impression that the FX transmisssion is geared so low that it may be detrimental to use it on a SM.

[Kurlon]

I'd say it depends on the track. Normally I'd say F transmission, close gears so you can stay right where you want RPM wise no matter where you are on track. For AMA at LRRS I'd go FX with it's wider spread. That should give you speed for the pavement while not lugging in 1st in the dirt.

[csmutty]

I think the FX tranny would be better for sumo. In order to get the top speed needed with a mx bike the starts in first are always challenging, requiring lots of clutch work to get them going. I think it would be an advantage to have a sumo with a lower first gear.

[tls25rs]

Think the review I was reading said the FX trans 1st was liking going up 13 teeth in the rear, 2nd up 8, third up 2 and 4th and 5th were pretty similar to the F. Those seemed like really big jumps over the F.

Good points about the starts on the typical 450 variants.

[Kurlon]

At some point I'll grab actual gear counts and plot them vs the old school 90s era YZ vs WR to see just how different they are. Even with a tiny powerband my WR250Z gearbox didn't feel gappy at LRRS or Boxshop?

[csmutty]

Think the review I was reading said the FX trans 1st was liking going up 13 teeth in the rear, 2nd up 8, third up 2 and 4th and 5th were pretty similar to the F. Those seemed like really big jumps over the F.

Good points about the starts on the typical 450 variants.

They are big jumps, but with the crazy wide power band of the 450 I don't see that being a problem either.

I think you should buy one and be the test pilot

[nhbubba]

The more I read, the less I understand the WR with the FX on the scene.
WR should be road legal, 50-state plated. My understanding is that it is sold with mirrors in most of the RoW.

Should be

F => MX (compete with KTM SX)
FX => enduro (compete with KTM XC/XC-W)
WR => dualsport (compete with KTM EXC)

Or something.

[nhbubba]

I think it would be an advantage to have a sumo with a lower first gear.

Would/could it not be a better plan to gear a bit higher, fan the clutch on start with the rest of the field and take maybe slightly longer legs on the straight?
Advantage every lap but the first vs just the start.

[breakdirt916]

Ya race application f the short/wasted first gear....get up to speed as soon as possible and wail on that clutch!!!

[Kurlon]

The other bit that separates the WR from the F/FX is state of motor tune. Locked down ecu, softer cams/timing, maint intervals and time between the grenade pin needing to be reset should be longer on the WR.

[tls25rs]

Would/could it not be a better plan to gear a bit higher, fan the clutch on start with the rest of the field and take maybe slightly longer legs on the straight?
Advantage every lap but the first vs just the start.

The way I understand it is that the gears at the high end are the same from the F to the FX therefore the top speed gearing will not change between the two. The advantage of the FX vs. the F transmission would be that it would be easier to launch, less clutch abuse needed, and it also may make some of the corners where an F might be between gears, too slow for the higher and too fast for the lower, the FX may have the spacing between gears to account for that. May or may not be better but it would be different.

This would also make it theoretically possible to launch harder with the gearing that is set up for higher speed without as much clutch abuse. Typically though the top speed of one of these bikes isn't necessarily dictated by gearing more by the lack of power to pull the gearing.


Edited for clarity:

Just realized that I may have been agreeing with you all along

[breakdirt916]

I like wide service intervals

when a bike goes cablooie I take my sweet ass time fixing it...minimize that

[nhbubba]

This would also make it theoretically possible to launch harder with the gearing that is set up for higher speed without as much clutch abuse. Typically though the top speed of one of these bikes isn't necessarily dictated by gearing more by the lack of power to pull the gearing.

What I was saying was why not gear (sprocket) the thing to the moon. Fan the start with the rest of the field and take the top-end advantage on the straight.
But if the motor can't push the gearing, then it doesn't matter. Imagine motards aren't the most aerodynamic things on earth either.