USD headaches...

Hey guys I'm working on a usd swap for my bike which is a 96 XR600R and swapping it to an 03 CRF450 fork setup. Now the problem is I keep reading about machining down the stem to fit the R's bearings but I just don't see how that will work. It looks to me like when you machine down the stem it will take away the threads from the crf450 stem. Is there a bearing conversion for this? I've heard about all balls having a swap lot bit I can't seem to find it on there site. Any ideas here guys? I've seen a lot of them done to these bikes but haven't seen a solid write up on one just the finished products. Any help would be wonderful thanks!:cheers:

the easiest way to do it is have a machinist make you a set of bushings that are press fit on the stock xr stem,

the bushings will have a id that is a press fit to your stem and the od will be a press fit to fit the crf triple tree, .it allows you to run your stock bearings,check mine out in my garage, you can also make the bushing on the bottom a slip fit and use a set screw through the triple tree to hold the bushing from spinning, this is what I did,you can also make the top bushing a slip fit, and use green or red permanent loctite this method worked great for me and allows me to change the bottom bearing without having to press out the stem and a press is not needed to place the stem in the lower triple tree.

hope this helps :cheers:

I had though about doing something like that. but what did you do about the threads at the top of the steering stem? it seems that if i turn it down it will take off the threads from the crf stem. also the xr stem doesnt have the large smooth service at the top between the thread sets like the crf stem does. sorry for the questions but im having a hard time wrapping me head around this for some reason.

ok quicker question, did you use the xr front wheel and brake or the crf?

I used the stock xr stem and crf 450x triple tree the bushings slip over the stock stem to make it fit in the crf triple tree no need to change any threads you use the stock xr stem just make the bushings, take your xr stem and your crf triple tree to any machinist and tell him to make you a set of bushings out of aluminum so that the stock xr stem will fit the crf triple tree he will understand.

I used a crf front wheel,you can use the xr brake caliper but you need a crf caliper mount to make it work, if you try to use just the xr caliper and the xr caliper bracket you will not have full braking contact:thumbsup:

just a note I forgot if you do the bushing make sure you taper the id of the bottom bushing to clear the retaining ring on the stem:thumbsup:

Or use a 90/91 CR stem, The press fit is the same as all the honda USD triples so no mod needed there, machine the lower bearing journal to press fit the XR bearing. The top bearing is already the same as an XR so no mod is needed. Buy the Emig triple clamp bushing and put it together. I've done 4 sets this way. It's pretty easy. Use the matching wheels and brakes for your set of forks.

Thanks for the input guys!

drtlvr, so how do the set screws hold up? that sounds like a good idea for servicing and all but also seems like a lot of stress on those things. I guess im not 100% sure where the stress points are on the steering system but i would imagine after landing a jump or hitting a set of whoops would put a lot of vertical force onto those points.

valvesrule, I never heard about the cr stem I will have to look into that.

I have one 1/4 20 set screw located on the lower triple tree right in the center on the backside, the set screw just hold the bushing from spinning it is not drilled into the bushing or the stem, I am sure this adds no stress what so ever

ok well i got the stems apart and the bearings out. been trying to look up the part numbers for dimensions but haven't had any luck so far. I though i read on here before that all balls makes a bearing swap for this. is that true? I haven't been able to find anything on there site.

call them and tell them what you need they do have them but they are twice the cost of the stock bearings:thumbsup:

Part number 99-3540-5.I have these in my 95 xr600 with 04 crf250 clamps and forks.Need to be carefull on the install races are very thin.Hope this helps.:cheers:

Thanks for the input guys!

I never heard about the cr stem I will have to look into that.

Once you turn the lower bearing seat it's basically the same as doing a complete rework on a CRF stem.

Alright well I got a machinist at work turning up some bushing for me (haven't been in a bit so i didn't see the part number for adapter bearings...:cheers:). could take a little longer then i want since he is doing it on the side but what you going to do.

Again thanks for the help! Ill update withe some pics when i get the clamps back in the next couple of days.

Ive got a fresh 04 CRF450r Front end, like new, revalved by Precision Concepts, that will be going into my 97 XR600 which already has 91 CR500 f/end revalved by Factory Connection. I just got a lot going on now to do the swap, but cant wait to get the CRF frt end on.

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