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Only $10 for all 2026 SX, MX, and SMX series.
A 120 kit will make that bike have 7 Horsepower instead of 6.5.
I will add, ignore anything you see from lungbutter.
Any of you guys swap the forks on your 100's? My girl rides a 2004 and she bottoms out every time it leaves the ground.
Welcome to the club!
So, you got your boy a lighter XR100. Nice! I’d be inclined to check out the crank in that thing since it’s got a few years on it and I’d also check out all the gear box internals…clutch…etc.
There are all sorts of goodies avail for the XRs.
Good luck!
The Shop
DeCal Works Huge Plastic Inventory of UFO and Polisport kits.
Luxon 4-Post Bar Mounts
$189.95 - $239.95
Fork springs and other goodies avail for affordable prices.
Heavy weight fork oil and a spring spacer will help. It's not worth going any further than that.
Yessir it definitely needs some work. I haven’t looked at the clutch but assume it’s toast. I’ve thought about replacing the crank while I’m in there but the money adds up and I’m not sure if it’s worth it.
Do a bit of searching and seek out an XR100 forum…there are some rebuild kits out there that’re affordable. Do your homework and find out who makes the good stuff.
Have fun with it. Those are great little motorcycles.
Those XR's are made to last. I've still got my '88 XR600. Handed it down to my son after racing HS for 10+ years. Valve adjustments and some suspension work and new plastics. He managed to kill it riding at the Stillwater 500 every day after work for a couple of years but he can destroy a Sherman tank with a rubber mallet so I don't count that.
I used to ride my little KE125 over to Bury St. Edmunds from Mildenhall RAF and watch John Banks burn laps on the early XR. Not sure if it's true but I was told he had a hand in development. He was a 4 stroke badass.
Honestly, I have back to 1993 models of XR 100's and I think I have only done 1 crank in all of those years. I run 10w40 yamalube and haven't had any issues. You can ask Plowboy, mine get no mercy.
Well, I finally got around to tearing her all the way down. Doesn’t look too bad. The gears are not all rounded off and chewed up. Quite a bit of metal shaving due to the cam and cam journals. Timing chain and sprocket are ready for replacement. Is there anything I should pay particular attention to here that I may be overlooking? The rod bearing has zero up and down movement using a dial indicator. Don’t mind the table cloth or mess. We use what we’ve got and not what we wished we had.
That was quick. I'm no XR100 expert, but I would check the valves and seats to make sure they aren't leaking. Also, with the cam in place, make sure there isn't any play in the cam to indicate worn journals. Make sure the clutch basket doesn't have any big grooves where the plates ride (I don't think this bike has enough power to do that anyway, lol)
You can also measure the cylinder bore if you have the right tools.
Clutch basket looks good. I’m going to replaced the clutch kit and get a 115cc kitaco house brand cylinder, piston and assembled head. The old head assembly passed a water test. The cam tore up the cam journals. That’ll all be replaced as well as an oil pump, cam and cam chain.
Looks like you got it under control. Your work will make that bike last a long time under minimal maintenance.
Replace those cam chain guides and check the sprocket on the crank, it will come off with some heat.
When you're done making sandwiches, go buy a bigger bike then STFU! Welcome aboard, sir!
He’s got a crf125 for xc racing, a klx110 and a klx140. This 100 is just a play/practice bike. Want a sammich?
Pit Row
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