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USD Fork upgrade on XR400

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Hi there!

 

So I'm considering a swap from stock to a pair of usd forks on my XR.

My girl is in her twenties (97) and was a sow when I found her earlier this summer.

As far as I can tell, she never got any proper love during her lifespan and I keep on finding all sorts of signs of previous abusive treatment and fixes.. she deserves some too far prolonged love, and that's exactly what I will give her!

 

Back to topic and the swap!

As I said, she's a 97 xr4 and the donor is a 10 crf450. Plan is to put the usd's from the latter on the xr and I wonder what I should and shouldn't, can and can't regarding this swap?

Bolt on? Refab? Custom made orders?

Appreciate all tips and tricks you can share, a how to from someone who've done this mod would be lovely!

 

Happy riding!

 

 

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did you measure the od of both forks where they fit the clamps to see if they are a match????? or are you going to swap the trees with the forks?

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did you measure the od of both forks where they fit the clamps to see if they are a match????? or are you going to swap the trees with the forks?


Well the plan is to swap it all if possible?
Heard somewhere that it's doable.
Don't have the usd's in my possession atm, so can't measure.. but aren't the 08 and up 48mm? May be wrong there, just a number I recalled from somewhere.
Will do some measures later to be sure

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If I go with the trees from the xr, I will probably end up scratching my balder part of my head a lot figuring out how to get the tire and breaks match up.. don't mind going for the full front from the crf since most of the parts on the xr front is old and busted, didn't lie when I said she's a sow

2 sips in on my first coffee of the day, so my brain activity is a bit dampened yet this morning

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well if you have the whole front end youd only have to measure the upright tube (the one with the head bearings on) to see if its within adjustment range for the xr frame and that the bearings are the same diameter. the only other thing I can think of is the steering stops, offset and mounting holes ext.  you don't want the trees, bars or forks hitting the tank on full lock. sounds like fun good luck with it and let us know how you go.....cheers

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well if you have the whole front end youd only have to measure the upright tube (the one with the head bearings on) to see if its within adjustment range for the xr frame and that the bearings are the same diameter. the only other thing I can think of is the steering stops, offset and mounting holes ext.  you don't want the trees, bars or forks hitting the tank on full lock. sounds like fun good luck with it and let us know how you go.....cheers


Then we think exactly the same! My mind wanders away to some old post I read about a similar swap and there they mentioned something about the bearings is a tad too wide, but back then there was a company producing custom bearing kits to make this type of swap as bolt on it can be.
The offset on the crf front should be 20 if I remember my friends words correctly (he's a crf guru, knows all years by heart down to the tiniest washer).
Steering stops are pretty much none existing on the frame, so prob need to fix that. Guess they've let her eat the ground quite a lot and verry hard cause they're smashed out like warm lead on the frame.
So when I fix the stops I can easily align and adjust the appearance of them to fit the forks stops properly.

When I start the project I will most definitely post the whole thing here as a step by step how to with pictures, will try to document all problems and solutions I encounter during the swap.

As it is for now, I mostly gather more knowledge to prepare for the swap.
Will probably start by this seasons end, she'll get a huge rebuild this winter and I will probably do the swap at the same time.


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cool I bet your looking forward to the rebuild  its good fun bringing these old girls back from the dead good luck with it all and I look forward to seeing your progress...cheers

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cool I bet your looking forward to the rebuild  its good fun bringing these old girls back from the dead good luck with it all and I look forward to seeing your progress...cheers


Yeah, I really do look forward to it!
Already done huge changes, all documented ofcourse! She was alive when I found her, but barely.. she was so &%$#@!ed up by twats thinking they're super mechanics, turning her to a supermoto freakshow
Cut of half of the subframe, grinded of all fix points for the airbox, no airbox, bolts as stunt pegs.. list can be made humongous!

20170617_161758.jpg

That's how I found her


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WOW that's crazy does it even have an air cleaner???? some people need to be shot for the shonky crud they do.....I hope you plan on bringing it back to some what normal.

you going to change it back to white like it would have been???   still cant get over the huge hole in the middle with no air box he he strange...

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WOW that's crazy does it even have an air cleaner???? some people need to be shot for the shonky crud they do.....I hope you plan on bringing it back to some what normal.
you going to change it back to white like it would have been???   still cant get over the huge hole in the middle with no air box he he strange...


Luckily they had put a "reusable" steel airfilter straight on the carb Not that it makes much difference from it to be completely without But hey, they atleast tried to do something right!
I will put her into as close to original appearance as possible, except that I went for red/white/black instead of oem white

Will soon head of to work, will snap some pics of what I've done so far on my way out.
I use her almost daily, and she seems to like the love I smear her with so far


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sweet I like to see pix when im not working on my own.....keeps me dreaming:rolleyes: at least whit red/ white and black it will breake up the black....think itl look heaps better.

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20170704_205110.jpg20170703_205834.jpg20170703_205823.jpg20170617_135350.jpg

Camchain tensioner broke during ride, shut her of almost in an instant when I realised what have happened! Camchain was the worst I've ever seen, so put in a stronger one from a crf450 and a manual camchain tensioner.

They've mounted the clutch wrong, take a look at the 2 discs in the first groove where it should be only one
End result of that was an engine full of aluminum flakes and a pressure plate milled down a couple of millimeters

The valve seals was oem still, so leaked as a cows bum!
Exhaust valves are done for, so she still burns some oil.

Reusable oil filter with wind-up steel wire as a spring

Man, I love the nutheads who laid hands on her before me!


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20170801_120307.jpg20170801_120316.jpg20170801_120330.jpg20170801_120250.jpg

Todays look!

Airbox substitute made out of a plastic oil can

Bike stand fix that works for now

They really liked the reusable steel filters, crankcase ventilation

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looks heaps better with the red and white plastics... are you going to re paint the frame and bits with the rebuild???  still so much better than all black.

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looks heaps better with the red and white plastics... are you going to re paint the frame and bits with the rebuild???  still so much better than all black.


Have crossed my mind to powder coat the frame and all other parts they painted, looks strange with the cherry red doesn't it?
Will put a red or red/white headlight cover later on, probably with some cree flood leds


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yehh it does. looks a purple/ maroon  colour  in the pix.  powder coat is good stuff but would it last with the heat of the engine oil in the frame?? and what colour would you go??

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yehh it does. looks a purple/ maroon  colour  in the pix.  powder coat is good stuff but would it last with the heat of the engine oil in the frame?? and what colour would you go??


Haven't decided colour yet, perhaps oem colour?
Good point there, need to get a IR gun to see what temperatures I get on the oil frame and match the paint to sustain the heat!

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