My 96 kx500 has always been one of the most dependable dirt bikes I have ever heard of. I have a v-force, fmf pipe and silencer, and a steahly flywheel weight, otherwise the motor is stock.
I do not know how old the top end, I have owned the bike for about a year and it is in very good condition. The bike spend 99% of it's time as a wood/trail machine riding with my son on his KTM SX65. I dont open it up much at all.
Yesterday, I was jumping some small jumps and climbing some near verticle cliffs and just having fun, nothing real fast and 2nd and third gear at the most. I got on a little straightaway and opened it up and had it pinned in 5th gear. There may have been a "pop" back fire sound but I cant really be sure. It was not loud it if was. The engine kept pulling and running great like it always had but it was smoking like a freight train. It still made as much power as always.
I hope that the slow speed stuff just mucked up the pipe and when I opened it up the stuff just started burning off. It was really a steady stream of smoke, not the usual puff-puff-puff. These bikes smoke alot to begin with but this was a real noticable change.
The bike has always started on the third kick and a few months ago had 120 psi compression cold.
What could make it smoke like this?
I really hope to make it thorough another summer before I tear it down, do a top end, balance the crank, port the cylinder,....
I did not do anything other than ride yesterday. Everything was fine for about an hour. I did not add any gas before the problem either. I run Motul at 40:1 in premium (91 octane) plus a little octane boost.
Thanks in advance for your response. I will probably tear into this this weekend.
Jay