KDX220 won't run right

[big gear head]

I've had this '98 KDX220 for a few weeks, but I've only had it out 2 times. The first time it was not running right, but still had pretty good power. The second time it ran ok for a little while, then it left me stuck on the side of a hill 2 times. It would run all right just off idle, but when I opend the throttle it would bog like the choke was on. I did a leak test on it and it was leaking real bad. Over the past 2 weeks I've been working on it. I rebuilt the carb and did a complete top end rebuild with a new Wiseco piston kit. I put a new Clarke tank on it while I had it apart. I tried to install the FMF fatty pipe that I got with it, but it wouldn't fit. When I got everything back together yesterday and warmed it up it still ran like the choke is on. It also won't idle on it's own. I have the idle screw all the way in and it still won't run on it's own. I did another leak test on it and it's sealed up tight now. Any ideas what might be wrong? It has the stock pipe and silencer on it.

[scheckaet]

sounds like jetting.
read this: http://www.kdxrider.net/forums/viewtopic.php?t=1156
also are you running fresh gas or did you run old gas with new gas? what oil ratio?
might be fouling plug too.
Did you support the kips shaft when you did the top end?

[big gear head]

I've read the jetting topic and I've got some jets ordered. I just don't have them yet. The gas is fresh and it's mixed 32:1 with Kawasaki oil. I did support the shaft and I checked the timing on the valves several times before finishing everything. I did not check to see if the valves were opening after I got the engine together. I'm not sure if that cover will come off with the pipe installed.

Could this be something in the ignition, or maybe the silencer is stopped up? Can the stock silencer be cleaned out? I'll have to look that up in the manual tomorrow.

[jlogan]

Check the pipe. The person I bought my kdx from was working on an old ktm and had something similar. Found out that mice had made a nest in his pipe.

He said he actually had it happen before on another pipe and he threw it into a coal furnace in his garage, and burned the nest out.

That's about as technical as I get.

[big gear head]

Here is what I've done so far. These are posts from another sight where I asked the same question.

The reeds looked like they were almost new. No space under them. They set flat against the block. I think they have been replaced receintly. The carb went together well. I replaced some parts, but the needle looked very good. I have a new one coming, but I doubt that I needs it. I set the float level with the sight tube, so I'm pretty sure that it's not the problem. I checked the valves several times as I was putting it back together to be sure that they were in time and free. I didn't check them after the engine was running to see if they were opening, but I don't know of any reason that they wouldn't. I might try to get the cover off of the shaft to see if they are opening.

I'm going to check the manual to see how to clean the spark arrestor. It might be cloged. I was wondering if it might be something in the ignition that's causing the problem.

The plug is the same one that was in it when I bought the bike. I cleaned it with carb cleaner and checked the gap. It seems to be all right, but I bought 2 new plugs and I'll try one of them. The filter is clean. I even took the filter out and it didn't help any. I already lowered the clip on the needle and that didn't help. When my new jets get here I will see if that makes any difference. I'm also going to check the ignition timing to see if it is off.

OK, I took the plug out and beat on the silencer while the bike was running. When I took the plug out there was a lot of oil that ran out all over the brake caliper and wheel. If any carbon came out it was very little. I also checked the spark plug again and it was a BR9ES, so I put in one of the new BR8ES plugs that I bought. It's back to running like it did when I bought it. If I take it easy in 1st gear it's all right, but if I open the throttle all the way it doesn't pick up much. If I put it in 2nd and open the throttle it will bog and then it will pick up and pull hard. When I got done I noticed that there was oil on the swing arm again where it's blowing out around the seal between the pipe and silencer. This was in 5 minutes or less.

I took the cover off of the mag and there was water in it. Not a lot, but some. I'm going to pull the flywheel and check the timing marks and clean out all of the water when I get time. I'm also going to take the carb back off and figure out why the idle screw isn't doing anything. The air screw is not doing much either. If I turn the air screw all the way in the bike will stall, but that's about all it does.

[big gear head]

I pulled the fly wheel off and there wasn't any rust on it. The timing seems to be set right. I might try removing the silencer and see if it runs any better. I'm about to run out of ideas on this. I'm going to look into the carb again, but it's going to be a few days before I get a chance to do that. I still haven't got my new jets. I ordered them over a week ago.

[stomlinson]

My friend jays 98 kdx 220 is doing the same thing if u figure out the problem please send me the solution because we r tired of messing with it.

[SS109]

Where did the water come from? BTW, I would replace that idle stop screw as I have never heard of a plastic version, like you mentioned on TT, for the KDX.

Anyways, it still sounds like a jetting and/or carb problem IMO. What PJ/MJ are you currently running? Carbs can be a real pain to get clean. It may look it but there may be some internal passage plugged.

[big gear head]

The PO must have torn the gasket on the cover and there was a big chunk of the gasket missing. The water came in from me riding or washing the bike. From the look of the inside it has been like this for a while.

I wish I had another carb to get parts from. I had the carb that came off of my '87 KDX200 when I replaced it with the carb from a KX125, but I gave it to the guy that bought the KDX200 about 20 years ago. I don't know where to get the correct screw for it. Right now it has the original 42PJ and the 145 main jet. I lowered the clip on the needle 1 groove. I'm still waiting on my new jets.

[rsr02]

BTW, I would replace that idle stop screw as I have never heard of a plastic version, like you mentioned on TT, for the KDX.

The idle screw on my '97 220 is plastic, and have no reason to belive its not stock.

[scheckaet]

they are plastic. must be thinking of the AIR screw...

[big gear head]

I took the carb apart again and I can't find anything wrong with it. The idle screw is working, but even when it is screwed in all the way the bike will not idle. All ports and restrictions in the carb are open. I can't find any reason for it to be doing this.

What is the air screw suppose to look like on the end? Mine is flat. I expected it to look like a needle on the end.

[stomlinson]

I think he is talking about his idle screw my buddy 98 has a black plastic end on it but the whole screw isnt plastic, we r going to do a compression test on his bike next. This is really strange that we r both having the exact same problem on the axact same year and model. But if changes plugs his bike will run pretty good for a ehile then like u say its like the chock is on cause it starts to smoke really bad untill it stalls then it wont start again. We r also if the compression test goes well, going to drop the mj to 142, and pj to 40.i cant believe if 2 of us r having the exact same poblem that others havent. Experianced this issue before??? Come on kdxriders dig deep into those brains and lets figure this out cause its wrecking my riding season constantly screwing around with my friends bike.......... By the way my rb tuned 91 200 is insane now rob blacks mods along with the 2003 kx front forks make my girl something to be recond with, I really want to meet up with a ktm 200 on the trails!!!!!!

[Julien D]

I took the carb apart again and I can't find anything wrong with it. The idle screw is working, but even when it is screwed in all the way the bike will not idle. All ports and restrictions in the carb are open. I can't find any reason for it to be doing this.

What is the air screw suppose to look like on the end? Mine is flat. I expected it to look like a needle on the end.

it's flat on the end, to hold the slide up.

Is there any chance your carb has been dipped? If so, I'd bet the rubber gasket for the jet block is leaking. Had the same problem on my buddies 200 and never could get it worked out. Had to replace that gasket before we could even BEGIN to jet that bike.

[KarlP]

It sounds to me like a jetting issue. I can't see where you list what jets are in there, or needle clip position.
A 140 mj 40 pilot on the 220 in warm temperatures and sea level should run pretty good. I used to run 140/38.
You also mention putting a piston in it in your first post. Are you sure you have enough running time to break that in? Usually a fresh piston will not rev out for a bit.

I'd ride a bit more, adjust jetting and keep a fresh plug in it before trying anything else.

[big gear head]

The idle screw has a taper on the end, but I was wondering if the air screw should be flat or pointed. My air screw is flat. I was wondering if the end might have broke off.

The mj is 145 and the pj is 42. The clip is in the 3rd groove from top. I might try it in the top groove and see how that works. It was in the 2nd groove.

It's running the same now as it was before the new piston. I've had the jet block out several times and the seal looks fine, but I'm going to replace it because it might be too flat.

Thank you all for your ideas. We'll get it figured out eventually.

[scheckaet]

air screw is tapered but flat at the tip.

[gregp]

My '04 200 has similar issues lately. I have a V-Force reed cage, an FMF woods pipe, a silencer, and it is jetted correctly. My bike does not want to rev out unless I hold it wide open for far longer than I am comfortable with, and things get super hot. I suspect that I have to disassemble the top end and de-carbon everything (ports, power valve assembly, etc.). I recently switched from Klotz to Amsoil Interceptor, and I do not believe that they like each other at all. I did drain my tank and float bowl before making the swap, but I suspect that the top end is clogged up pretty badly. I have just been too lazy to get this done. I will purchase a new top end kit before I begin this operation, though.

[jlogan]

Gear Head,

Did you fix the problem yet?

[big gear head]

Nope, still trying to figure it out. I checked the kips valves and they are opening. I took the silencer off and it didn't help. I put the needle clip in the top groove and it ran a little better. It still won't idle no matter what I do. I took the air screw completely out and it didn't make any difference. I can screw the idle screw all the way in and all the way out and it makes no difference.