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View Full Version : Carb tuning on '82 XR250R



jimmy2r
01-21-2008, 11:03 PM
So I bought my 1982 XR250R with a supertrapp already installed. Bike ran great when I bought it, but I got bored one day and decied to clean the carburetor. Like an idiot I forgot when you pipe a bike you have to tune the carb as well. So when I put the carb back together I installed every thing according to the clymer manual that i purchased, and now it back fires and runs crappy. Does any one have any suggestions as to re-jetting, how many turns does the fuel screw have to be??? Or any thing eles to get my bike running good again.

bschultz
01-22-2008, 08:20 AM
Rejetting is not an absolute with being able to (tune) adjust the exhaust flow rate by adding or removing discs on a SuperTrapp muffler.
With everthing being the same as when you took the carb apart, there's really only a couple of adjusments that may be off. 1) Pilot/Idle jet (screw) or 2) JetNeedle (clip).
Back firing usually indicates a lean running condition. Your Clymer manual should have a carburetor tuning section or a web search will provide you with plenty of info on carb theory. DynoJet is also a good source.