Shifting roblems

Sounds like you may have a problem that will require dissesembly. You can try a quick fix of changing your oil with some 10w30 like kawi recommends. My KDX's have always hated 80w. Some run ATF. You can do a search on ATF and you'll find threads about trans oil until you're blue in the face. FWIW, I run Mobil-1 fully synthetic 30wt made for 4stroke bike trans'. I think it's MX4T, and I get it at Advance Auto for $6.99/qt. I like synthetics, and this oil contains no friction modifers that may cause your clutch to slip.

Couple things I would check...clutch cable, make sure it is in proper adjustment (~1/4" free play at end of lever) and not stretched out. Also, if you look behind the clutch basket (need to take off big right cover, water pump, clutch, etc-not too dificult) there is a spring that returns the shifter to center position. Make sure that the spring is in good condition, along with the plastic retainer inside the "loop" of the spring. Also check the pin and ratchet assembly for the shift arm behind the clutch basket, I once had problems shifting because the pin was warped.

Worst case scenario (you'll need to split the cases) -shifter forks/pins are worn, bent, etc. or the retaining clip for the 3rd gear is messed up, or the gear itself could be malled/stuck to shaft etc. Try the simple stuff first, obviously, and if that doesn't do it split 'em! (the cases!)

Best of luck, doesn't sound great though. :thumb: