450 Plastic on 426 COMPLETE WITH PICS

More pics



now that looks good, mmm white and blue :thumbsup:

Hi All

Am in the middle of a rear subframe conversion ,or my wr400 to wr 450 .Need some help from an inmate with regards to the top subframe bolt mount 6mm longer on the frame see pic 1 . do i make it 3mm smaller each side or take 6mm off the right hand side.

Also doing a counter sunk dipstic thread to suit a safari tank (see pic) will give me the full range of aftermarket seat & tank options that suit wr450 , on my much older wr400.

This conversion has been described as alot of fooling around , but worth it in the end , for modern plastics ,seat tank,etc.

Thank You



Wr400 safari tank conversion , of 05'' 450.

wr450 alloy subframe conversion to suit wr400

alot of work done .







Edited by rodsmetal

Love the way this looks. My most favorite yet.


Where did you get the sticker kit and what tank did you use?

You guys are awesome for figuring all this out. I'm doing the swap on my yz426 sumo this winter. It's getting a general overhaul, big brake kit, auto decompression cam, new sprockets/chain, few other random things, but I figured i'd update the styling while I was at it. got all the parts I need with the exception of the tank, which is on it's wait to me in the mail. I know I read that the yz450 tank fits and the wr450 tank doesn't because of the oil fill, but I'm gonna see if I can reshape it enough to fit. if not I'll just buy a yz tank and seat instead, but I'd really enjoy the extra half gallon of the wr tank. I'll make sure to take pictures and post everything on here in case anyone else is still looking into doing this swap, although I know this thread is a few years old(although that just makes it that much more worth updating the styling)

I have an 02 yz426f, what's the newest 450 front fender and number plate that fits? Just curious bc they look amazing

The current front fender can be fit by modifying the two front bolt holes.  Don't know about the number plate.

ImageUploadedByThumper Talk1408827959.603692.jpg

450 front fender and number plate

ImageUploadedByThumper Talk1408828019.650063.jpg

Hi, doing my '99 400 now ( have owned it past 14 years hehe ) and want to know what '03-'05 parts can be used. There is a guy local to me selling his '05 250F airbox and subframe. Will try and get the rear brake master as well.

Will the 250F airbox boot fit up to my original 400 carb ? Will this prevent me from doing the '05+ carb mod later ?  Amazes me that the airbox boot lines up at all. I guess it works as it has been done countless times here on TT right ?

Looking for confirmation, thanks ! ( decided to keep the old beast as a backup )


On edit : OK read through entire thread : 250F - 450F '03-'05 all same for body conversion.

Looks like the same rubber boot is used, just transferred from old airbox to new one.

It's all good and have a 250F '05 subframe and airbox on way in locally. Will use a new black

Clarke 450 tank and get a new SDG seat and side panels. Cool !

Edited by Shawbridge Husky

Picked-up a local to me sub frame and airbox last night off an '05 250F. Looks like it was abused, not up to my primo clean habits at all..

Brought it to shop today and chased the threads, straightened it as it was tweaked ( more adjust later on bike ) and

shaved inner / upper clamps to 2.400" inside measurement.  Did this by using our disc sander machine with guarding removed.

A small angle grinder would work also but this was easier to control. There are no threads inside the attachment point so will use

an aircraft nut, will be close to shock res. but there is ample space. I ended up shaving most of the meat off on the upper inside

right hand clamp per suggestions here earlier. I only cleaned up the other mating surfaces to make it tidy. The 400/426 frame

has an offset tube welded at that junction, I assume the 450's is centered thus reason for this mod and the right

hand side grinding required.


I'm mounting up my airboot to the airbox now, drilling some holes and using all I could from the original.

I removed the inner lip on the airbox with a die grinder and a small angle grinder as well.

What I ended up with is a constant thickness, no more boss for the 450 hose clamp mount style.

Not 100% necessary but decided to do it to make it same as older method. It does end up a little

thinner compared to original box which is practically structural to the sub frame.

Best of both worlds, cheap and light but with the original boot and steel clamp with bolts to solidify

the whole works. I think I'll add in some washers there as the studs protrude past the nuts more

than before and the tin tends to deboss in when tightening. 


I cleaned it all up, redid some rivets and corrected some flaws.


On edit : I used the steel clamp plate as a template to drill the 6.0mm holes. Worked

like a charm.


Must say the quality of the 400/426 stuff is top notch and built to last, but heavy. The 450 stuff is so much lighter

but quality is bad, airbox is flimsy. I also found the 450 welds poor compared to the 426 stuff.


Have a tank coming in next week from eBay. may do the carb upgrade while at it. This bike has been

sitting for 10 years.

Edited by Shawbridge Husky

Complete eBay tank on way in for 100 with petcock, shrouds, gas cap and mounts. 100.00 shipped.

Original blue, look super clean from an 03 450.

Stoked !

The part numbers for the 450 subframes are different for 03, 04, 05. I read here that the 05 subframe is a little lower, but what differences are there between 03 and 04?


Are there any newer plastics (meaning newer than 05) that can be easily swapped? 

Wow, cool to see this thread is still going after all these years. My 426 just sits in the garage with the rest of the collection now, but it still looks sweet!. :thumbsup:

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