KDXRIDER.NET

Hello all. Just joining the forum here recently, have reviewed many posts / topics but would like to bring some few things together in one place. Recently picked up a 2002 KDX 200 for my son and I. Bike seems to be running well, no major issues other than cosmetic type stuff, I hope. Possibly heavy white smoke, but not sure if it's 2 stroke smoke or something else. Plan on testing compression this weekend. If I'm doing a once over on this bike, what should I be going through?
Also, has anyone seen excessive carbon buildup in aftermarket exhausts on these before? After shutoff on a longer ride I'm seeing heavy smoke continue from the exhaust, but not sure where to go from here. Any and all help is appreciated.

Congrats on the new bike. They often, usually, smoke. Just my experience. But you might want to do a plug chop test and start checking the jetting, AFTER, cleaning the carb (do NOT soak it).
Yes, to the excessive build up in the pipe. BTW, what pipe is it? One of the best things you can do for these bikes is switch to an FMF pipe.
Do two things first though,
(1) Get a manual. I happen to like the Cyclepedia online one, others like printed. But get one.
(2) Go to this website: https://www.frpoffroad.com/. and read.

Good luck! These bikes are outstanding and excellent even today.

Just throwing out ideas. Compression test like you said. For the carburetor, I would just buy a jet block gasket. You never know what the last owner did.

Is the white smoke steamy, or oily? Leak down test will tell all.

Welcome.

I would check the steering bearings, linkage bearings and swingarm bearings. A lot of dirt bikes are bought with those areas having a bit of neglect.

All the above. Compression check and leakdown will give you a good idea of overall engine health. Definitely linkage/swingarm/suspension bushings/bearings along with wheel bearings. They are always in the muck and most folks neglect them. If its an aftermarket silencer, repack it, and while you have the pipe off for a leakdown you can clean it out as well. Fresh plug, clean filter, go ride! After you post pics of course!

If your crank seals are leaking (20+ year old ones probably are) that will cause transmission oil to get sucked into the combustion chamber to be burned and will produce lot of smoke and spooge. You'll need to break the engine apart to get at the crank seals.