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2002 220R bottom end rebuild

Posted: 07:28 am May 12 2026
by KDX220rser
I was playing with an old Revloc DynaRing this weekend to see if i could get it to work(i couldnt). While switching between clutches I noticed some greyish milky oil in the case. I run Bel-Ray Gear Saver which is more of a red color. The bottom end of the KDX has never been rebuilt, so im thinking it may be time. My issue is, I'm not confident enough to do it myself. I have done alot of work on all kinds of bikes(my dad and i build this KX/DX Hybrid), but I made a major screw up on my 2009 KTM 250 xcw a few years ago(blew out a bearing seat on one half of the case), so Im not willing to try again with my Hybrid KDX build...

Question: Who/where should i send it off to have it completely rebuilt? Im thinking i should rebuild crank and everything while im at it? I have all the RB Design Head and Carb mods, but it doesnt seem like he does this kinda work anymore. Suggestions? while im in it, any other mods i should consider?

Re: 2002 220R bottom end rebuild

Posted: 11:21 am May 12 2026
by SpruceItUp
If you're seeing a milky colored oil in your gearbox it is likely that your water pump seal has failed.
Before anything I would do a leak down test with vacuum and pressure to see if your crank seals are holding properly.
I'm all for preventing maintenance, but if your bottom end isn't acting off I personally wouldn't rebuild it unless you know it has a lot of hours on it.
But if you're willing to spend the money it never hurts to do so.

Re: 2002 220R bottom end rebuild

Posted: 05:57 pm May 12 2026
by Chuck78
I second what Spruce said, sounds like you need a water pump rebuild, but I wouldn't split the cases early in the season unless the crank seals or bearings test bad.

You can't really test the #1 most wear prone bottom end bearing (the crank pin big end rod bearing) without having the top end off, but you can check the main crank bearings by grabbing the flywheel rotor and the primary gear on the left and right sides and wiggling them up and down.