I have a roughed up 1982 KX or KDX 250, Im not quite sure which. Any help on how to know for sure whether it is a 2 or 4 stroke would be nice, and any help on what I can and cant do (financially speaking, what would be the cheapest yet most effective) parts to buy for it would be awesome. Also, it wont start, it will turn over, but it not run. I replaced the spark plug, and the wiring is in okay shape. So im thinking its the coil? Any help?

 

Hey Whiskey, welcome to the forums. I'm not familiar with that bike, but as far as the 2 or 4 stroke, look at the pipe coming off the motor, if its 2 inches or smaller around, then its a 4 stroke, if it looks like a snake swallowed a small rodent, then its a 2 stroke, which will need mixed gas.

 

Pull the spark plug, and ground it to the motor while kicking the motor over, that will tell you if there is any spark, you have to start there before anything else.

 

The KX and KDX rides are all 2 smokes. (I like that snake and small rodent example deej.)

Get a new plug and keep it on hand, inspect the old one, clean it (that sometimes works) and do like deej mentioned to test for spark.

Welcome to KF

 

Thanks for the help guys, I used your advice and figured out that it is a two stroke, because as you said, the pipe looks like a snake swallowed a mongoose. I did the spark plug against the frame last night, and it arced a very beautiful blue charge against the frame. I tore it all apart this afternooon since I just got the bike and Im planning on putting a new piston in, and replacing all the gaskets. Im assuming the rings and possibly the original piston are completely shot. After the exhaust pipe came off, it spilled a load of black gas/oil all over the garage floor. To me, that means the there is probably little to no compression, which is probably why it wont start since all the gas is being blown by the piston instead of combusting in the chamber. I want to put an FMF Fatty or Gnarly pipe on the bike, but as expected, I cant find one that is made for this year of bike. Will newer FMF pipes fit? Im pretty handy with modifying things, I just dont want to buy a $200 part and figure out that it is totally unmatched with the bike and wont work at all.

 

Hook up your compression gauge, pull a compression test. You may be correct that the top end needs pulled, but documenting the reading is also good to know prior to dissassembly.

Call up FMF or the other exhaust manufacturers and get their recommendations on your exhaust requirements.

 

hey wondering if you still have this 1982 kx 250??