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YZ250FX parts interchange thread.

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FYI, here is some parts interchange information about the YZ250FX.  I dug into this stuff in order to figure out what I could move/share from my 2012 WR450F to the FX.

 

- it uses the new style Yamaha swing arm. The linkage bolt mounts beneath the arm, not through the arms.

 

- the rear axle diameter is 22mm.  This is the same as was used on the old swing arm.  I believe the YZ250F/450F with the new swing arm use a larger diameter rear axle.  For anyone swapping the new swingarm onto an old chassis it appears that the FX axle blocks could be used with your old axle to complete the conversion.  **I have not done or checked this, it just appears that way**

 

- it appears as though the old Yamaha (22mm) rear wheels work on an FX without any mods.  I'll confirm this in a couple days.

 

- it uses the new fork.  The upper fork tube diameter is 54mm.   The old upper fork tube diameter is 56mm.

 

- the front axle is 22mm.   The front axle on the old fork was 20mm.  I'm hoping that old style Yamaha wheels can be made to fit the FX with a simple bearing change.  I'll confirm this when I make it work.

 

- the fx fork uses 470mm long springs.  The old forks used 454mm long springs, at least on the WRs.

 

- it appears to use a 25mm triple clamp offset.  The first few years of reverse engine YZ450Fs used 22mm TCs.  Yamaha used 25mm forever prior to that.  

 

- the FX uses a YZ style TC, with a single bolt in the middle.  The old WR style didn't have the numberplate bolt and has 2 bolts on the side to mount the headlight.  Alas you can't simply bolt an old style WR headlight pod onto an FX.

 

- it uses the rubber mounted handlebar mounts.

 

- it uses WR footpegs with YZ (hollow) footpeg pins.  WR footpegs are SS, larger and weigh 0.5 pounds each.  YZ footpegs are Ti, smaller and weigh 0.25 pounds each.

 

- the FX shock is unique.  It is longer overall ?   I've read if you put a YZF shock on an FX the tire will contact the rear fender.   Left side reservoir, as are all reverse engine shocks.

 

If the FX shock is longer overall, using a YZ shock with a longer bumper (WR style is longer) might be an avenue to lower the seat height ?

 

The FX shock uses 275mm springs, according to the manual.  It has a 150mm stroke.   However, if you go to the Racetech website, they are recommending a 257mm spring and an adapter collar ? (652660, for example)  I got the 275mm length from the service manual and 257mm for the 652660 by measuring one I happen to have from my 2012 WR450F.  So it appears that the old shock springs will work on the FX. 

 

FYI, the stock spring length on a WR450F is 240mm, though Racetech also recommends 652660 for it also.  Maybe that is why the suspension action is so much nicer on the WR with an aftermarket spring ?

 

- the FX exhaust header heat shields are steel.  The heat shield on a WR450F is not steel, or at least not magnetic steel.

 

- the FX front brake rotor is 250mm.  Standard on Yamaha forever.  The 2016 YZ450F gets a 270mm rotor.

 

 

Here is a summary.

 

Swingarm  - new style, no bolt through the arms

Rear axle - old style, 22mm

Fork - new style, 54mm upper diameter

Fork spring - 470mm

Front axle - new style, 22mm, not 20mm

Footpegs - WR, larger, stainless steel

Footpeg pins - YZ, hollow

Shock - Unique to FX

Shock spring - 275mm, but old springs will work ?

Handlebar mounts - new style, rubber mounts

Front brake rotor - old style, 250mm

TC offset - 25mm, not 22mm

TC style - YZ, not WR.

Edited by MidlifeCrisisGuy
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Thanks for the info. I've been thinking about swapping the shock spring with my 09 yz 450 that I only ride a few times a year. The rate is only .1 softer on the 450. I'd like to have the ti spring on the bike I ride.

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FYI, here is some parts interchange information about the YZ250FX.  I dug into this stuff in order to figure out what I could move/share from my 2012 WR450F to the FX.

 

- it uses the new style Yamaha swing arm. The linkage bolt mounts beneath the arm, not through the arms.

 

- the rear axle diameter is 22mm.  This is the same as was used on the old swing arm.  I believe the YZ250F/450F with the new swing arm use a larger diameter rear axle.  For anyone swapping the new swingarm onto an old chassis it appears that the FX axle blocks could be used with your old axle to complete the conversion.  **I have not done or checked this, it just appears that way**

 

- it appears as though the old Yamaha (22mm) rear wheels work on an FX without any mods.  I'll confirm this in a couple days.

I have a YZ250 19inch Excel on it now. It works. Tire will rub with studs or if you are reasonably fast and hit big jumps on the track.

 

- it uses the new fork.  The upper fork tube diameter is 54mm.   The old upper fork tube diameter is 56mm.

 

- the front axle is 22mm.   The front axle on the old fork was 20mm.  I'm hoping that old style Yamaha wheels can be made to fit the FX with a simple bearing change.  I'll confirm this when I make it work.

 

- the fx fork uses 470mm long springs.  The old forks used 454mm long springs, at least on the WRs.

 

- it appears to use a 25mm triple clamp offset.  The first few years of reverse engine YZ450Fs used 22mm TCs.  Yamaha used 25mm forever prior to that. 

It is a 22mm offset

 

- the FX uses a YZ style TC, with a single bolt in the middle.  The old WR style didn't have the numberplate bolt and has 2 bolts on the side to mount the headlight.  Alas you can't simply bolt an old style WR headlight pod onto an FX.

 

- it uses the rubber mounted handlebar mounts.

 

- it uses WR footpegs with YZ (hollow) footpeg pins.  WR footpegs are SS, larger and weigh 0.5 pounds each.  YZ footpegs are Ti, smaller and weigh 0.25 pounds each.

 

- the FX shock is unique.  It is longer overall ?   I've read if you put a YZF shock on an FX the tire will contact the rear fender.   Left side reservoir, as are all reverse engine shocks.

Shaft is 4mm longer on the FX

 

If the FX shock is longer overall, using a YZ shock with a longer bumper (WR style is longer) might be an avenue to lower the seat height ?

 

The FX shock uses 275mm springs, according to the manual.  It has a 150mm stroke.   However, if you go to the Racetech website, they are recommending a 257mm spring and an adapter collar ? (652660, for example)  I got the 275mm length from the service manual and 257mm for the 652660 by measuring one I happen to have from my 2012 WR450F.  So it appears that the old shock springs will work on the FX. 

 

FYI, the stock spring length on a WR450F is 240mm, though Racetech also recommends 652660 for it also.  Maybe that is why the suspension action is so much nicer on the WR with an aftermarket spring ?

 

- the FX exhaust header heat shields are steel.  The heat shield on a WR450F is not steel, or at least not magnetic steel.

 

- the FX front brake rotor is 250mm.  Standard on Yamaha forever.  The 2016 YZ450F gets a 270mm rotor.

 

 

Here is a summary.

 

Swingarm  - new style, no bolt through the arms

Rear axle - old style, 22mm

Fork - new style, 54mm upper diameter

Fork spring - 470mm

Front axle - new style, 22mm, not 20mm

Footpegs - WR, larger, stainless steel

Footpeg pins - YZ, hollow

Shock - Unique to FX

Shock spring - 275mm, but old springs will work ?

Handlebar mounts - new style, rubber mounts

Front brake rotor - old style, 250mm

TC offset - 25mm, not 22mm

TC style - YZ, not WR.

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Older shock won't work because the body is longer on the FX, therefor allowing for it to be longer but with less stroke. The shaft and everything else is the same length as the YZF though.

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It is a 22mm offset

 

 

 

Source ? 

 

I've got a 22mm offset TC from a YZ450F on my WR and the TC on the FX is different.  The FX TC seems to have more separation between the fork tubes and the steering head.

 

I can't measure it with the bars on.  I will if I ever take them off.

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I have a YZ250 19inch Excel on it now. It works. Tire will rub with studs or if you are reasonably fast and hit big jumps on the track.

 

What size tire and studs are you running ?   I test fit a studded IRC M5B 130 on an 18 inch rim and I'm worried the studs are going to contact the stock muffler and tear it to shreds.   I've got an FMF Ti Powercore on the way.  I'm hoping the clearance will be better with it.

 

My FX came with a 110 on it.  Seems small, but also seems to work well.

Edited by MidlifeCrisisGuy

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Older shock won't work because the body is longer on the FX, therefor allowing for it to be longer but with less stroke. The shaft and everything else is the same length as the YZF though.

Multiple tests and literature says the shaft is 4mm longer. I have not measured it myself.

Source ? 

 

I've got a 22mm offset TC from a YZ450F on my WR and the TC on the FX is different.  The FX TC seems to have more separation between the fork tubes and the steering head.

 

I can't measure it with the bars on.  I will if I ever take them off.

In a magazine test, I will try and find it.

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What size tire and studs are you running ?   I test fit a studded IRC M5B 130 on an 18 inch rim and I'm worried the studs are going to contact the stock muffler and tear it to shreds.   I've got an FMF Ti Powercore on the way.  I'm hoping the clearance will be better with it.

 

My FX came with a 110 on it.  Seems small, but also seems to work we

Running a CST Surge Intermediate 110/90/19. This was on my KTM 350 SXF as well as YZ250. The rear rubbed the mud guard and marked up my Yosh RS4.

 

I'm about to build a new set so I can use my spare 18inch wheel on my FX.

 

I've run a 19inch rear on my FX and it rubbed the muffler on big jumps or flat landings. With an M5B those studs will get awful close I wold have to think...

Here is what I run: http://www.brunowessel.com/catalog/index.asp?display=item&itemid=8

 

I run M5B rears on my FX, 120's right now. I wont use an M5B for a studded tire. Kenda Millville and Washougals seem to work well, this CST has worked well also.

Did you run the IRC last season?

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We are off topic... should start a thread on studded tires on the FX and other Yamahas ?

 

Running a CST Surge Intermediate 110/90/19. This was on my KTM 350 SXF as well as YZ250. The rear rubbed the mud guard and marked up my Yosh RS4.

 

I'm about to build a new set so I can use my spare 18inch wheel on my FX.

 

I've run a 19inch rear on my FX and it rubbed the muffler on big jumps or flat landings. With an M5B those studs will get awful close I wold have to think...

Here is what I run: http://www.brunowessel.com/catalog/index.asp?display=item&itemid=8

 

I run M5B rears on my FX, 120's right now. I wont use an M5B for a studded tire. Kenda Millville and Washougals seem to work well, this CST has worked well also.

Did you run the IRC last season?

 

I bought the studded M5Bs used with wheels for a good price.  Not necessarily what I would build today, but worth running to test.   The builder used Gripstuds.

 

Your studs look really interesting.  Do lose any ?  How is the price compared to the Gripstuds ?

 

I run M5Bs on my WR.  They seem to grip well and last and stand up to sharpening with a knobby knife.  Properly sharpened the end of life traction is still pretty good.

 

Thanks for the replies.

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I really like the M5B as a dirt tire, I think its great. I have 2 new ones waiting to go. The 120 works perfect on the FX in my opinion. I have a 130 that I will try next. For studs I think the knobs are too deep.

Grip studs seem to work well too. They are more money than conventional studs but easy to install.

I lost one stud on my current set, but I know how to ride with them on. Some guys with 450's that like to constantly spin the tire lose more studs.

We use a stud gun and have a collar fabbed up so the studs go in perfect every time. No glue. We tried using glue but it makes too much of a mess with the gun. Some friends of mine run another set with short studs for the shoulder season.

 

Last year I rode at least once a week for the winter season and hit my buddies MX track quite a bit as well.

In April I moved 5 hours inland compared to the coast where I was before and they get way colder temps and more snow so I don't think I will get as much riding in. Studs really are only good on hard pack,ice or crusted snow. Deep snow just does not work.

 

Feel free to start another thread on studs!

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My FX has the exact same axle as my 08 WR. My Pitbull trailer restraint setup fits both the same, so I'd imagine the spacing and all would be the same.

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