2003 KDX 200
V-force reeds, airbox cut off, FMF gnarly pipe
42 pilot 155 main jet
needle lowered by 1 front middle (circlip moved 1 up from center)
The big bogs at very low speeds under heavy load going up a hill.
This is my GF's bike and she got stuck on a ditch on a steep hill so I had to ride it out, I found myself having to clutch in to rev up and drop the clutch to get the power to normalize again.
Air screw and rear sprocket. If you do alot of slow up hill you'll need a 49 tooth.
I was using a 40 pilot and 152 main. changed to a CEK needle seconf clip fro the top (She'd probably prefer the DEK) and dropped to a 38 pilot. Dialed in air screw, perfect jetting, no bog uphill or anywhre with stock gearing. 49 was too tall I could ot keep wheel from spinning with my mids. I have the RB carb and R head though.
After doing some reading, it seems tons of people have trouble with what I'm describing. Is it possible that the KIPS valve is siezed/broken? I only notice bogging under heavy load up hills.
Don't dump the clutch. If you feel the bike slowing and beginning to bogg on an uphill, grab the clutch, raise the rpm's and ride the clutch up the hill. I found that KDX clutches can take a lot of abuse.