KDXRIDER.NET

Hi I have an 86 KDX200 that takes upwards of 20-40 kicks to get it going. It has 165 psi compression, new piston/rings, new plug, new reeds, intake boot and Keihin PWK35 air Stryker carb. Fuel is mixed 32:1, when I get it running it will not idle, if I pull the choke on it doesnt impact how it runs. Aside for the lack of idle it does rev out nicely w/ and w/o load. Prior to the PWK I had a Mikuni VM34SS and the behavior was the same. To get it running i need to dump some fuel down the plug hole, which after a10-20 kick it gets going and the carb feeds the engine fine. I’ve checked the spark and it seemed fine, but the thing that is unique is the stator, flywheel, CDI, and coil are from the 84-85 series KDX. I’m wondering if this is the problem or is it possible I have air leak in the bottom end like on the crank seal or other making it tough to start, but not leaning it out causing the idle to race. Any help would be greatly appreciated. Thx

I would do a leak down test. I've seen plenty of bikes in the past, when they have an air leak, take an excessive amount of kicks, and sometimes adding fuel like you did, to get them to fire up. You said it wouldn't idle at all so my bet is someone fattened up the jets to compensate for an air leak. The leak down test will tell you for sure.

Of course, not sure on the ignition for those years but if everything was swapped, which you listed it was, it should run fine with it.

Thx I have a leak down tester that I need to figure out how to connect to intake boot. Can only connect to spark plug hole right now.

Definitely need to do a leak down on it. Compression is only part of the equation. If it fires manually priming it not likely the electronics. Have you pulled the flywheel and looked at the seal condition/check for evidence of leakage?

Found 3 problems:
1. Power valve shaft seal leaks badly
2. Cylinder and piston have some pretty nasty scratches…how it ever held 165 psi I’ll never know
3. Rotor and stator soaking wet w/ a 1/4” of wet clay/sludge collected below the stator. Everything on the rotor stator are corroded

Sigh, looks like i need to replate cylinder, already cleaned up the rotor/stator, will need a new piston/rings and of course fix the power valve shaft seal.

#3 was any of that oil? You did the leak down test and the crank seals were ok?