- Mar 23, 2010
Hello All. Thanks for taking the time to read this. I was riding a couple weeks ago at Bear Creek and the throttle on my 1990 KX500 stuck wide open. Engine kill did not work but I was able to get the bike layed over and it stopped after 8-10 seconds of rev-out (the bike is jetted quite rich). After getting home and inspecting it, I realized the intake boot had split at the clamp and allowed atmospheric air into the cylinder. Poor maintenance and inspection on my part. I installed a new boot and throttle cable and began the pain-staking process of a cold start (I really do need to look at jetting and perhaps a decompression valve). I noticed right away backfiring upon kicks. Then the same when I was roll-starting it (that's usually how I get it going at the start when it's cold). Backfire upon backfire. New plug installed before last ride and plug was quite wet when I pulled it. Fuel making it past combustion cycle and out exhaust port- I can see it on the pipe. Something has obviously changed substantially since the throttle stuck. I suppose a tear down on the top and and checking rings/piston/cylinder would be a good idea but perhaps after checking a few other things first? Any ideas and suggestions would be greatly appreciated. Thanks!