USD fork swap on XRR

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USD fork swap on XRR

Post  codswallop on Sat Jan 08, 2011 5:34 am

I recently got a set of 05 CRF 450R forks and everything else I need to do the conversion. I just have to get the upper fork clamp machined. The forks have been re-valved and sprung to suit a 220lb rider. I weigh 228lb with all my riding gear. Is the extra weight of the XRR over the 450r going to be a major issue, or do you think I should get them valved and sprung to suit the additional weight of the XRR. Any input would be much appreciated. Cheers.
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Re: USD fork swap on XRR

Post  Hew on Sat Jan 08, 2011 11:43 am

I was warned off doing this conversion for dirt riding but advised to modify the original forks instead. It was something to do with strain on the headstock which I can't see myself but went a different way. It will be interesting to now if anyone else has heard this and if they can expand on the story.
I loosely followed the instructions from this excellent site, drilling out the compression valve and adding light oil. This made a massive difference on the tight stuff I ride and instead of being bounced around riding over rocks and ruts it soaked it all up
http://borynack.com/XR650R/xr650r_forks.htm

One thing it has not done is change the balance of the bike. The XR still feels front end heavy compared to other bikes I ride. This makes it harder to pick out narrow lines and I just tend to blast over the top on the xR instead Smile .

If you go with the CRF forks and I would love to hear what difference they make. I guess the set up will need tweaking to suit the type of riding you do as much as anything else. the advice I had from a top rider is that you need to be using at least 90% of the fork travel. Any less and the forks are too hard. If you bottom out a lot apart from extreme jumps then they are too soft

Good Luck
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450R forks on an XRR

Post  codswallop on Fri Jan 28, 2011 4:22 am

Hi Hew, thanks for the reply. I'd actually visited his website before and was going to order the stiffer fork springs and shims. I viewed every page of his website and noticed right at the bottom of one of the pages that he had actually changed to inverted forks. As far as I can see, his website was generated in 03-04, when availability of a set of secondhand USD forks was pretty scarse. I have seen a few comments about damage to the headstock, but if you check out the yahoo groups XR650r forum you'll see plenty of guys that have done the conversion and swear buy it. They say the bike feels 20kg lighter and handles more like an MX bike in whoops and soft sand. I got the forks, clamps, front wheel, axle, disc, caliper and master cylinder and lever for less than $500, it's all off an 05 450R. A guy was parting out his CRF on ebay. I'll let you know how it goes when Ive done the conversion. Cheers from Cambodia.
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Re: USD fork swap on XRR

Post  BuRP on Fri Jan 28, 2011 10:46 am

Yeah, please do inform us here?
Sounds interesting, especially the/your "... the bike feels 20kg lighter and handles more like an MX bike in whoops and soft sand.. ".
Sounds almost too good to be true but I'll take your word for it once you'll post here.

So Hew,
you did the mod - still feel it was worthwhile, even when the front-heavy lenience is still there?

Got stock forks still, std-oil also, all dated 2007, that's why I ask.
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Re: USD fork swap on XRR

Post  Hew on Fri Jan 28, 2011 5:32 pm

Agree it is great info on the upside down forks.

If I had not done this mod to the standard forks I would not still have the PIG. It has allowed me to really enjoy the bike.
For me the mod was a 100% improvement. Prior to drilling the valve I had really struggled when riding with lighter trail bikes This was a bit embarrassing at times as I was the ride leader. The front wheel would just get deflected right off line on rocks, roots and ruts. I wound all the settings right off and this improved things but it still was no where near what I would like. I had already replaced the whale snot,put into the forks by the factory, with a light oil.

Re reading the web site showed there was a way to improve what I had.
I have not adjusted the shims in the stack, there was not a lot of difference from standard to what I wanted anyway.
I did put lighter oil approx 4 weight ,should have been 2.5 but could not get it at the time.
and drilled the valve out to 3.5mm

First ride out showed straight away that it was much better. The nearest trail to me is ideal for testing how plush the suspension is. After a few tweaks I found my best setting which just off the softest. There is no doubt it can still be improved but it is near enough for me.. My valves off a 2005 bike originally had 1.9mm holes but another valve I saw had 2.5mm holes so the difference may not be as great.

It is mentioned in the article that Honda were concerned about the forks bottoming out off big jumps in desert racing and that is why they restricted the hole size. There are no deserts in the UK and the most my wheels are likely to leave the ground is about 2 to 3 feet as I blip it down rock steps. which it still soaks up with ease.

Yes it is feels heavier and less nimble than my 450 Berg but it is now a pure pleasure to ride. The only cost was the oil and that needed changing any way. Cool
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Re: USD fork swap on XRR

Post  BuRP on Sat Jan 29, 2011 8:28 pm

Yeah, and I need to put real oil in too, hearsay has it the std stuff aint good. Well, I have to clean it properly anyway for that, so I'll do this mod then too, coming winter when my workshop is ready.
The link for the making of tools has disappeared. I think I can make them with the text at hand, but anything particular or special one has to watch out for, toolwise I mean?
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Re: USD fork swap on XRR

Post  Hew on Sun Jan 30, 2011 2:14 am

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Re: USD fork swap on XRR

Post  BuRP on Sun Jan 30, 2011 1:49 pm

"403 Forbidden"

It's either me that site doesn't like or it's gone.
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Re: USD fork swap on XRR

Post  Hew on Sun Jan 30, 2011 7:23 pm

Opened straight up for me.

here is a link to the site and not the page I am sure that you will have come across it anyway.
http://www.xr650r.us/
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Re: USD fork swap on XRR

Post  BuRP on Sun Jan 30, 2011 8:42 pm

Thanks Hew, it finally does work now - persistence apparently pays Wink
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Re: USD fork swap on XRR

Post  Starkman on Sun Mar 20, 2011 1:09 am

Any update?

I have a set of USDs sitting in my garage but I'm concerned that the swap will change the handling. I like the way it steers just would like to be able to take bigger hits at speed without bottoming.
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Re: USD fork swap on XRR

Post  vinceguy on Wed Jan 25, 2012 1:51 pm

i'd like to hear more about this conversion. I'm planning on doing it in the near future but i want to be certain as to what parts i need. I'm planning on slimming my pig down and making it more enduro-race ready and i think this mod will help with cleaning up the sloppy front end.


This is what i gathered so far:

-05-08 CRF triples are best suited because the steering stops are equivalent with the XRs stock setup
-02-03 CRF forks are best because they allow the XRs caliper to be used without mods (this is more of a question)
-Evolution sells a top bearing that will allow you to use the CRFs larger diameter headtube and avoid machining and sleeving the triples(for the XRs shorter/smaller diameter headtube) --also more question than fact
-I plan on buying a CFR front wheel with rotor so i can use the CRF axle and not have to mess with spacer issues.

Am i missing anything? I feel like more needs to be done to fit the triples on (more than just the new bearing from evo)
I found tons of parts on ebay and it seems ill be able to do this job for under 600 bones (forks, triples, bearing, wheel)
Any input would be helpful
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Re: USD fork swap on XRR

Post  B45HER on Tue Aug 07, 2012 4:10 pm

I have had 3 650's now one from brand new and have just bought a 4th. I have had KTM WP forks on one and CRF forks on the other 2. It makes a huge difference to the handling and the bike does feel lighter.. Dont ask me why because I counldn't give you a technical answer, I only did it because it looked better and figured there was more adjustment etc with the newer usd forks. It does sharpen up the front and I much prefer the ride compared to std forks. My 2c anyway.. listen up
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Re: USD fork swap on XRR

Post  TomXR on Sun Oct 07, 2012 12:01 pm

Hi
Let me ask.How did you install the WP forks? did you change the triple clamps as well or used the stock ones?
Next year I want to use my bike as SM and thinking about this conversion.
Thanks


Last edited by TomXR on Thu Aug 15, 2013 8:07 pm; edited 1 time in total
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Re: USD fork swap on XRR

Post  babuja on Tue Apr 16, 2013 2:07 pm

I've done this mod after serious crash





After that i've rebuild it using some CRF Showa suspension and triple clamp i get from ebay.



Showa suspension was revalved, new springs installed and prepared on a suspension MX specialist.

This is the best mod i've done on the bike. Front is incredible precise and bike just seams to pass obstacles and roughn terrain so much smoother. If you could see the suspension working, is so much perfect how it absorves all the irregularities...that's the reason it seems lighter Bump

Haven't notice any issues regarding front/rear imbalance...bike suspension just as good as it can be set to.

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Re: USD fork swap on XRR

Post  Chris_w_65 on Fri Oct 11, 2013 10:28 pm

BuRP wrote:Yeah, and I need to put real oil in too, hearsay has it the std stuff aint good. Well, I have to clean it properly anyway for that, so I'll do this mod then too, coming winter when my workshop is ready.
The link for the making of tools has disappeared. I think I can make them with the text at hand, but anything particular or special one has to watch out for, toolwise I mean?
I made the tool but also made a mistake - The only pipe I had was old plumbers pipe and it is rusted inside so when I took my forks apart all sorts of crap came out the pipe. I somehow need to remove the rust from in the pipe (any ideas?) - Finishing assembling forks tomorrow - Special tool is not necessary if you have an air tool.
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Re: USD fork swap on XRR

Post  Chris_w_65 on Fri Oct 11, 2013 10:32 pm

BuRP wrote:Yeah, and I need to put real oil in too, hearsay has it the std stuff aint good. Well, I have to clean it properly anyway for that, so I'll do this mod then too, coming winter when my workshop is ready.
The link for the making of tools has disappeared. I think I can make them with the text at hand, but anything particular or special one has to watch out for, toolwise I mean?
Have you replaced the oil in your suspension yet?
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Re: USD fork swap on XRR

Post  stev0 on Thu Apr 03, 2014 11:23 pm

I have also read that the OEM suspension is better suited off road than the CRF USD's. How much better though? I often slap some road wheels on mine and yes its no real 690SMC, it can be fun with the sagging suspension and everything.
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Re: USD fork swap on XRR

Post  bigkuri on Tue Apr 08, 2014 10:35 pm

Old thread Smile

Interested too though in any real information on fitting 48mm KTM forks to the bike, as I have a spare set kicking around, plus the appropriate front wheel. No triples though.

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Re: USD fork swap on XRR

Post  stev0 on Tue Apr 08, 2014 11:21 pm

I know of a guy locally that fitted 48 LC4 forks on his 650R. He loves it though.
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Re: USD fork swap on XRR

Post  bigkuri on Tue Apr 08, 2014 11:25 pm

Just noticed you have a crap taste in bike's SteveO... Wink

Get his details and stuff! Smile Would love to know how, as the KTM forks are just going to waste. I think they are off a 640 Adventure.

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Re: USD fork swap on XRR

Post  Hew on Wed Apr 09, 2014 12:15 am

It should be quite straight forward if you use the KTM yokes/triple tree clamps with the XR steering stem fitted to the bottom yoke.
You may need to adapt some steering stops.
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Re: USD fork swap on XRR

Post  bigkuri on Wed Apr 09, 2014 9:53 am

How do I go about that? Not done anything like this before.... I guess get the ID bearing size of the KTM yokes, and the OD bearing size of the Honda stem? Find suitable bearings, and then work on the steering stops?

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Re: USD fork swap on XRR

Post  Hew on Wed Apr 09, 2014 12:07 pm

There are likely to be two differences between the KTM and XR yokes. The diameter of the bearings and the length of the stem.
By fitting the XR stem to the KTM yoke you keep the standard XR bearings and the stem should be the right length.
Obviously before starting you would need to compare the two stems.

You could be very lucky and find that the KTM stem is comparable in length to the XR stem and if the diameter is slightly different on the ID there may be a bearing that can match the ID of the stem to the OD of the XR steering head.

The stem is usually a press fit in the bottom yoke so this would need to be driven/pressed out of both yokes. Depending on the diameter of the hole in the KTM yokes it may need a spacer to make it a press fit. Or get a new stem turned with the diameter and length the same as the XR but the part that fits in the Yoke to match the KTM fork.

Good luck
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USD

Post  Chris_w_65 on Tue Jun 03, 2014 3:47 pm

I am going to look at a set of CRF450 USD forks and triple clamps tomorrow - Apparently they are off a late model. Can all the CRF forks be made to fit the BRP?

BuRP - Do you want a set if I can get?

I may be getting the rear master cylinder of a CRF - Must just check the mount hole spacing - Why? - Because it looks nice with the reservoir in the cylinder  banana

Anyone know if a CRF rear shock fits on a BRP?
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Re: USD fork swap on XRR

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