KDXRIDER.NET

I have a 2000 KDX200. I have the RB head mod (set up to run race fuel) and a newly modded RB carb. The issue I am having is that anything over 1/4 throttle it just spits and sputters like it is to rich and loaded up. I lowered the pilot jet from a 42 to a 40, raised the clip position on CEK needle to 2nd from top, and went down from a 152 main jet to a 150, air screw is about 1 1/2 turns out. Went riding today and had to turn back as I could not get it to run good in the upper rpm's. It's not smoking a lot, I thought maybe a blown crank seal but I don't think its that. I'm either thinking maybe the timing maybe off, powervalve is not working right or not at all or it is electrical or maybe even the reeds might be bad (boyesen power reeds). Possibly a bad coil or sparkplug wire or maybe even the CDI box too. I am going to take the seat and tank off and make sure all my electrical connections are good but after that, where do you think I should start? Any help is greatly appreciated. It just started acting like this a couple of months ago. I might even try a 50/50 mix of race fuel and pump fuel to see if that helps. Race fuel is VP110 or if that is not availiable I use TRICK 114. Thanks again for any help
Little Jeff

PS if I wanted to check the timing, is the nut holding on the flywheel cover a LH thread and where should the timing marks be set at?

Have you checked the compression with a gauge?

Might be worth playing with the jetting some more. I have the same bike with exception to the head mod and find the RB'D carb to be a little more touchy than before as far as getting it to run right.

Top end was done 2 years ago when it was replated. I don't ride this bike all the time as I have a KTM also so it should still be really good. I really hate the process of elimination
Little Jeff

dirty, gumbed up carb?

Well, I think I may have found the culprit. When I took the seat and tank off to check all the electrical connections, I decided to pull the spark plug. The electrode was very, very thin. The gap was double of what it should've been. Apparently I hadn't changed it in over 2 years. Bought a new $3 plug and now she runs like a raped ape, up and down the street anyways. What really makes me sick is that I didn't have an extra plug and even if I did have the plug, I could've gotten it off because my KTM sparkplug wrench wouldn't fit the plug because of the coolant hose and block was in the way. I drove 160 miles round trip and couldn't ride because of a $3 plug. I guess it could've been worse. Oh, it was worse, on the way back to the truck, my front end hit a rock or root or something and it tweeked my back. It hasn't been a good day.
Thanks for the input guys
Little Jeff

danm as i was reading this i was thinking its probably the spark plug (had the same issue with my scooter)..

too bad i didnt look an hour earlier.... wouldve been my first helpful contribution to a forum!! my favorite one at that!

That's just dumb

Mr. Wibbens wrote:That's just dumb

So you're saying you've never done anything dumb like that?
Little Jeff

Wibby is just poking fun at ya. Don't take it personally.

Gotch ya. Who all lives in Washington state? We should make a just KDX ride.
Little Jeff

Little Jeff wrote:

Mr. Wibbens wrote:That's just dumb

So you're saying you've never done anything dumb like that?
Little Jeff

I always carry an extra plug or two