Nothwoods
New Member
Hello, I’m looking for advice on a 2003 XC800 that won’t go over 70 mph. It’s got 1800 miles, bone stock, with carbs. For the most part it runs pretty well, and has decent low speed power although maybe not what an 800 should. I’ve cleaned the carbs and rebuilt both clutches with stock tuning. If the throttle sensor is plugged in it coughs and backfires and stalls, but the sensor tests fine and I’ve adjusted it to spec so it reads 4 volts at WOT. Runs fine with the sensor unplugged. I’ve run it with the throttle monitor unplugged and no change, and I’ve tried the different key settings for premium fuel with no change. Flat out on the lake it was only pulling about 68-6900 rpm. I found a bulletin for an updated CDI, and I got hold of one and now it pulls about 7000-7100 rpm. I’m not trying to turn it into a rocket, just would like to have it running properly. Mostly I’d like to know if anyone has any info about the problem with the throttle position sensor. Thanks for any help!