KDXRIDER.NET

Hello,

I recently acquired a 2000 KDX200 and have been trying to dial it in. It was running rich when I got it, I installed a 42 primary jet which helped. It was running well at full throttle, not too much smoke. I took it to a sandy Michigan trail a couple weeks ago, and ever since, it has been blowing tons of smoke at 1/2 to full throttle. Like huge clouds behind me after I give it some throttle, it definitely doesn't seem right and is worse then before. I checked compression, it is around 135 psi. I checked the air cleaner, it is good to go. I checked the muffler, it is newly packed and unclogged. I replaced the jet block gasket. The float seems approximately correct, I did mess with it to no avail. I installed a 40 primary and 145 main to see what would happen, it still blows a ton of smoke. I will probably go back to the 42 and 150.

As far as I can tell, it isn't burning oil, but I maybe haven't ridden enough to see a difference in the oil level. Any ideas on what the issue is? Burning coolant or oil? Is it normal? It doesn't seem to accumulate anything while sitting, it smokes a normal amount on startup, the extreme smoking is only at 1/2+ throttle.

Current mods:
145 Main
42 Primary
R1174K Needle 3rd notch
FMF Pipe
FMF Turbinecore II Muffler

What color is the smoke?

If it's not blue smoke, then you need to do a leakdown check. Even if it is blue you need to do a leakdown check if its billowing clouds. You won't notice the oil loss until you've ridden it for a bit. Coolant you would notice the loss, and smell it. My guess is crank seals

Gasoline brand and octane??

Two-stroke oil and ratio??

Spark plug brand and model?

Too much information is not enough. :-)

93 octane, not sure where from
Lucas semi synthetic 32:1, no idea what the last guy ran
NGK BR8ES

It appears to be white smoke. I fashioned a leakdown tester and it goes from 15-0 in about 3 minutes, not good from what I have read. It's hard to tell where the leak is coming from, any ideas on next diagnosis step?

Well, you don't want to put 15 psi in on a leak check, 5 psi is sufficient and should hold for at least 5 minutes. Likely a crank seal internally if you don't notice any leaking from the exhaust/carb areas. Next step is to open it up (split the cases)

White smoke? Open your radiator cap and do another leak down at 5psi and see if you can hear air come out of the radiator.

Try 6 psi, not 15!