KDXRIDER.NET

Sorry to dig up this old post but I have Been at it the whole day and am still stumped...I have exactly the same issue...motor 100 % ..2002 KDX 200 carb new jets and same with old... been completely stripped and cleaned 4 x now... new jet block gasket, removed and checked twice to make sure it was not squashed during assembly..been up and down on pilot jet sizes and no difference.. Will only idle with he idle adjustment screwed all the way home or maybe max 1 turn out.. I have been working on 2 strokes and carbs for ages and I simply cannot see why...fmf gnarly and power core 2. Just re packed. All orifices are open and cleaned...I 18mm float height...have no idea where to from here, any help would be appreciated.

3 things I can think of off hand would be

Reeds cracked or old and not sealing

The needle jet (hole where the needle goes in and out) is oblong. Look at that very close

The slide is worn out

It’s hard to believe that a slide that looks good can cause the same issue you’re describing but I know first hand that it does

Thanks for the reply. So the bike has barely any hours on it and has stood most of its life, still had original tyres when I got it a couple weeks ago..The carb is very clean and there is basicaly no wear in the carb. I compression tested it and was showing about 140. It will only (barely) idle with the screw all the way in. So today I found the powervalve is not working which I will have a look at tomorrow but not sure if this could cause the issue issue am having? I took the pipe off and looked into the barrel which looks glazed... the reeds do have tiny gaps but from what I have read a small gap is not an issue? When I take the carb off after testing I find little puddles of fuel in it, is this normal? When I rev the bike and place my hand behind the silencer it seems to spray wet black fuel with each rev.... really am stumped here... tomorrow I plan to pull the top end and see what's going on, try polish the glaze off the barrel and sort the kips out.

If the cylinder is stock, be careful in your cleaning. An oil damp green Scotch-Brite pad (or whatever is equivalent in your area) is usually recommended.

Check the right side crank seal. This can be done by a pressure or vacuum test.