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00 RM125 USD Swap

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Since snow is flying here now I decided to tear into my XRL. Ive been keeping my eyes open watching for a good deal on some forks and was able to acquire a set of 00 RM125 forks (49mm Showas) and triples on EBay. I had hoped to use All Balls conversion bearings like Thumpinred did, but they don't make them for this swap anymore, bummer.

Time for plan B, so I decided to make the XRL shaft fit in the RM triples and use stock XRL bearings and seals. The RM shaft is considerably bigger diameter then the XRL shaft, this made it possible to build an adapter bushing to make the XRL shaft fit into the lower RM triple. I also drilled and tapped the shaft and further secured the pressed on bushing with a 5/8 flat head cap screw. This shaft mod is very robust and was pretty simple to do since I have access to a mill and lathe at work.

Here is the bushing next two the two different shafts.

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Here is the XRL shaft with bushing and bolt next to the RM shaft

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I then pressed this into the triple just like normal. worked like a charm.

The top triple required some .010" shim stock to make the appropriate fit.

Here it is bolted up to my bike using the stock bearings.

7c1c7e70.jpg

These forks are huge! I will be freshening up the forks with seals and bushings before I button everything back up, but I couldn't wait to see how they would look on the bike.

Now I have to decide wether or not to respring while I'm inside the forks. Stock rate for the RM125 is .42 kg/mm, I weigh 220 lbs. Should I bump up the rate to .47 or so? Or, will these forks be stiff enough without new springs?

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LOL... who would have thought that the Honzuki fork swap would catch on. They are great big fatties aren't they?! :thumbsup:You are doing the stem the right way I think. I struggled with the decision and would have gone the way that you did if I had easy access to a lathe and press. A file, vise and sledge are about as sophisticated as my "machine shop" gets.:busted:

I dont know about the springs. The RM250s were sprung a bit stouter than the 125s were... but I am also about 30-40 pound lighter than you. When I measure the sag on my bike, the front springs could actually be a bit lighter to get the sag "right". On the trail though, they rock... I wouldn't go lighter. If I was riding mostly street, I might lighten them up a bit. I wouldn't be surprised if the OEM RM250 springs didn't measure out darn close to perfect for your weight.

My fatties in the wild:

2011-10-30140829.jpg

Where in Idaho are you? Always looking for fellow pigers come spring-time!:busted:

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Red,

Your "leg transplant" swap inspired me to look into the 99-00 RM forks, and I found a set for a really good price, so I jumped on it. These forks really do fit up without too much trouble. I'm excited to get this done. Thanks for the inspiration and the manual.

I live in the Preston area.

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A couple of details for anyone else considering this swap.

The steering stops aren't right. I am adding 3/16" thick plates to the front of them to make them right.

The stock RM upper triple is thicker than the XR triple which doesn't leave mUch of the threaded end of the stem for the top lock nut. I got around this by thinning down the bearing lock nut in the lathe (I cut the stepped down portion off of the top side of the nut leaving the other to press on the bearing.) I also made a .020 washer to replace the stock one for the top side of the triple for under the top lock nut. There is also about 1/16" of raised section combined top and bottom on the RM Triple, I cut these off flush with the surface of the triple. My top lock nut is now flush with the top of the stem.

I contemplated threading the top of the stem to 5/8-11 and securing the top triple with a bolt and spacers. That would have worked too and without doing any of the other stuff I ended up needing to do to make it work.

Now to figure out my turn signals and headlight mounts.

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A couple of details for anyone else considering this swap.

The steering stops aren't right. I am adding 3/16" thick plates to the front of them to make them right.

The stock RM upper triple is thicker than the XR triple which doesn't leave mUch of the threaded end of the stem for the top lock nut. I got around this by thinning down the bearing lock nut in the lathe (I cut the stepped down portion off of the top side of the nut leaving the other to press on the bearing.) I also made a .020 washer to replace the stock one for the top side of the triple for under the top lock nut. There is also about 1/16" of raised section combined top and bottom on the RM Triple, I cut these off flush with the surface of the triple. My top lock nut is now flush with the top of the stem.

I contemplated threading the top of the stem to 5/8-11 and securing the top triple with a bolt and spacers. That would have worked too and without doing any of the other stuff I ended up needing to do to make it work.

Now to figure out my turn signals and headlight mounts.

The RM stem would have put you in a similar position. I fussed with how to solve the "short stem" dilemma in my build as well. I ended up picking up some space on the bottom end by flipping the grease seal around and not using the Thick washer that All Balls supplied. I noticed that they no longer show a conversion set for RM to XRL. I suspect it is because it is not a direct bolt on. The best solution is likely a custom stem that is a tad bit longer.

Steering stops? Yep they almost line up but not quite. I never worried about it. Mine are still "close".

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I got my forks rebuilt and installed. I'm also doing a few other mods to my bike while it is torn apart. New 12.0 kg/mm spring for the shock, CRF450 rear fender, CRF150F Front Fender, new ATV High bars, Trailtech Vector, Handguards, XR's Only Slip-On. I'm still working out some little details, but the bike is coming back together nicely.

Here's a few photos for anyone that might care to see my project.

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I attached the CRF fender with the turn signal bolts and these little aluminum tabs I fabbed up, it is rock solid.

12a1fdb1.jpg

73e12652.jpg

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I have a 94' xrl would this swap work on this year too. I am a big boy and would like a stiffer front suspention. and how about the axle and the brake cal. bolt on. Do you have to modify any thing there?

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What year forks will work with this swap. I know where I can get my hands on a set on rm 125 fork for about nothing but they are 92-93. model. wow this has got me excited about somthing else to spend money on. lol

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Not sure on the other year RM forks, what is attractive about the 99-00 RM forks is that they are USD twin chambered 49mm Showa forks. The older years might not be the upgrade you are hoping for? With access and ability to run a lathe and mill (or pay a machine shop to do it) you can make almost any forks fit.

The front caliper from the XR fits and will work, but not perfectly. I'm getting an RM caliper. You loose your speedo drive with this swap too since the XR wheel doesnt fit the RM forks. I'm putting a trailtech speedo on my bike to replace the stock unit.

Edited by Lane_N
fat fingers

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so I will need to use th rm wheel also?

Yes you will need to use the RM wheel. It works best if you get a complete donor front end off of an RM. oh... and the bolt pattern on the fender is also a bit different so you will have to redrill a red Honda fender to get it to fit.

P8010158.jpg

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2 questions. did you lose turning radius? my friend has (i think cr250)front forks and he cant turn has sharp as me. also did it make your bike more top heavy?

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I've only driven mine in the driveway so far, so I don't really know yet. Maybe Red can chime in with more details.

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2 questions. did you lose turning radius? my friend has (i think cr250)front forks and he cant turn has sharp as me. also did it make your bike more top heavy?

I dont notice a decrease in turning radius. I have not yet sorted out the turning stops so I rely on the rubber strap on my headlight hitting the tank as a stop. I guess it stands to reason that you will lose potential turning radius as the uppers on the USDs are a bunch fatter than the stanchions of the OEM forks.... but your stops dont allow the stockers to rotate all the way to the tank anyhow, so I guess it all depends on where you set your stops during the transplant.

Top heavy feeling? Not at all. If anything, the forks make the bike feel a bunch lighter and more nimble (as nimble as a 300 pound bike can feel:smirk:)

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One step closer to done with my swap. I got my front brakes sorted out.

The XR caliper bolts up but doesn't fit exactly right. See the pic.

dc419130.jpg

I picked up a caliper from an RM on eBay. The two bikes use the exact same calipers, only the mounting bracket is different. I swapped the brackets and bolted it back up. Much better.

dc77c0c4.jpg

Now I just need to secure the brake line to the fork guard.

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One step closer to done with my swap. I got my front brakes sorted out.

The XR caliper bolts up but doesn't fit exactly right. See the pic.

dc419130.jpg

I picked up a caliper from an RM on eBay. The two bikes use the exact same calipers, only the mounting bracket is different. I swapped the brackets and bolted it back up. Much better.

dc77c0c4.jpg

Now I just need to secure the brake line to the fork guard.

I have a ghetto solution for securing the brakeline... Trim off the curved ends of the existing brake line guide. Drill a small hole in each one and use wire clamps (not sure what they are called) from Lowes to secure the brakeline. If you want to do it right, you would want to get a set of fork guards from a newer RM that has the clamps on the guard.

P2090525.jpg

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This is encouraging to read. I've always felt the stock xrl forks were punny for such a big bike. I would like to keep the stock speedo 'cuz it's already there and easy for my old eyes to see. I guess I could save up for a TT. How did you handle the turn signal and headlight mounts? Also, would 125 forks work just as well? They seem to be a little cheaper than 250 units I've seen on ebay.

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This is encouraging to read. I've always felt the stock xrl forks were punny for such a big bike. I would like to keep the stock speedo 'cuz it's already there and easy for my old eyes to see. I guess I could save up for a TT. How did you handle the turn signal and headlight mounts? Also, would 125 forks work just as well? They seem to be a little cheaper than 250 units I've seen on ebay.

RM125 and 250 forks were the same. Springs may be different, but forks are the same otherwise.

Stock speedo will not work with RM forks. You will have to use an electronic one like a Vapor.

Turn signals are mounted to the top triple with the OEM L Bracket on mine.

I dont use a stock headlight. I cant answer that one.

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As usual Red is on target. I'm using a Trailtech Vector Speedometer. I just installed a set of Highway Dirtbikes Handguards, they are awesome. I have a weird bolt pattern on my bar clamps so I ended up having to make my own top clamp as HDB didn't accomodate my funky spacing. I'm mounting my Vector to the top clamp just like the HDB system does. I'm doing a homebrew LED dash built into my top clamp, still in progress. I ditched my factory ignition switch for a very small 2 wire one since I don't have the fork lock option anymore. I drilled and tapped a couple of holes in the front face of the top triple to remount the stock XR headlight bracketry, I am also fabbing up a small bracket to mount to the bottom triple to hold the bottom of the plastic headlight cover/numberplate. I built my own turn signal mounts, the bolts are on the sides of the RM triples versus the front on the XR's so the L configuration isn't what I needed. It is just a flat plate with a slotted hole on about a 30° angle to locate the turn signals. I'll take a few closeup pictures and post up so you can see what I'm talking about later on tonight. All in all a pretty simple swap, but lots of little details that have to be taken care of. I am a tinker by nature and like to build stuff. Most of this could have been done more simply, but where is the fun in that?

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