KDXRIDER.NET

My 1999 KDX 220 will not idle right. I've cleaned the carb, jets, and passages so many times, it's crazy. I've checked for air leaks, ect. One thing it's doing is it'll fluctuate rpms at idle. It'll idle how it's supposed to, then increase, then decrease. Also, if I lean it to the left just a little, the rpms will get higher. But once I hold the bike upright, the idle rpms get real low. That made me think float height. I checked it, and it was fine and working like it should.


The only mods are a fmf silencer and boyesen reeds. The jets are stock. 160 main and 48 slow. I believe that's stock, right?

Is it a slow jet problem? Because when I'm riding it, it's pretty boggy in first and second, but past that and at the power band, it runs great.

http://www.kdxrider.net/forums/viewtopi ... 105&t=1156

How many turns out from seated us your air screw?

I can take it all the way out and it does absolutely nothing. If I go all the way in, it dies.

Got the same problems two years ago with my 220, check your crank seals first no matter what you do with the bike if the engine is getting air from the stator side seal she will idle only when the engine is cold, just remove the the stator cover and check for oil or gas leaks to make sure you dont have problems with that seal. Another problem coul be the float height or bad jet block gasket. Hope this helps

superman27e wrote:The jets are stock. 160 main and 48 slow. I believe that's stock, right?

On the flywheel side of your cylinder, right where the reed block bolts in, there should be a 4 digit number. Yours isnt 1742 is it?

Yea, it says 1742.

You have a 200. Looks like the red KDX is at it again.

I was wondering why your "220" had stock 200 jetting.

Your jetting is likely too rich. I run a 40 and a 155. But as stated, you really have to go through the jetting process to find out for certain.

Wow. That dang red KDX. I always figured something was up. It has a purple seat, and I don't think the 220s had purple seats in 1999. If that's even the actual year model it is...was....I don't know, haha.

So where can I get different jets?

I use jetsrus.com

Thanks! I'll give it a try and go from there. Stay tuned, more crazy surprises from the infamous red KDX to come :p

I had one similar problem, my jets are 42, 145, and its fine for now, maybe you have rich jets, but the problem was in the cable witch is on the top of carburetor, when l move a little wheel left or right, he play with rpm-s, because wheel pull the cable for gas, up and down, and on the top of the carb you have one clip, on mine bike was worn, and l fixed it with one small extra wire inside and for now is fine...

superman27e wrote:Wow. That dang red KDX. I always figured something was up. It has a purple seat, and I don't think the 220s had purple seats in 1999. If that's even the actual year model it is...was....I don't know, haha.

look at your VIN, if the 10th digit is a X it is a 99