2003 xr100 rebuild

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5/20/2018 7:35 AM

New to forum but wanted to start new up to date post on rebuilding 2003 XR100R. Just bought this for my son fairly cheap. It was running rough cleaned carb and adjusted valves only to find a mess in the intake. There was a nest in the air box with seeds of some sort, filter was shot and there was a real sticky yellow mess causing intake valve to stay open. I removed engine after this now going to put bbr big bore on it and replace valves also. Any advice on carb? Upgrade? New jets or anything? I want to do it right for my son also it’s a project for us to do together so It’s meaningful for both of us. Any advice would be great!


5/20/2018 10:58 AM

Not sure if they make these for xr100s, but i put a R&D powerbowl 2 on my kx250f. I think it might have better throttle response than my 450 which is efi.


5/20/2018 11:53 AM

Not sure if they do I will research, thanks for the tip. Was reading some old post about upgrading to a 26mm carb


5/20/2018 4:05 PM
Edited Date/Time: 5/20/2018 4:06 PM

I have a ‘99 XR that I have had since 2000. Mine is bored a bit, has a Hot Cams cam, FMF pipe, and some porting...runs awesome. I’ve got a 105 main, stock pilot. I have always run the intake and exhaust at 0.004”. I pound the ever living shit out if it, and it still starts first kick every time.

Put a new timing chain in it too


Tomac and/or Anderson for 2020.....

5/20/2018 6:08 PM

Sounds awesome I’ve ordered bbr big bore , new valves, new jets , bbr rear spring , frame cradle, there’s a lot I want to do for him with this the more we think the bigger the bill is getting......also minor last things will be ... renthal 7/8 high cr bars , grips , asv levers, graphics (keeping original plastics actually in great shape) new seat cover you know the drill basically replace everything ha