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this is the craziest thing i can be riding for awhile and then i will hit a straight away go all out in sixth gear wot and the bike starts to cut out so i back off the throttle and only give it a 1/4 and it is fine its is like it is starving for fuel and it has a full tank the petcock filters are fine and it seems to be enough fuel the only thing that i have noticed is the fuel line going in to carb never is all the way full just has some fuel in it my bike is a 93 kdx 200 stock except for pipe as far as i know thanks for any help and if anyone needs more info just let me know

Change out your plug with a new properly gapped plug and see if it continues to do it. The last time I rode in the desert (really the only place to get it into 4-5-6th sustained) I had pretty much the same thing happen. Swapped out my plug in the middle of the ride and everything starting working correctly again.

-Maurice

thanks for the help what exactly is the corect plug gapping and what do you reccomend for a plug i currently use ngk br8es for a plug

I don't have my manual in front of me but I believe it is 0.7-0.8mm. The NGK BR8ES is a good plug selection for that bike. The stock BR9ES is too cold a plug. After you get your jetting spot on you can switch to a BR8EG which is a fine wire electrode and will give you a bit of a boost.

-Maurice

Check all the air lines coming off the carb. If one is blocked or even partly blocked, it may be inpeading the fuel going into the carb. You noticed that the fuel line isn't full. Mine is always full when on the bike at any speed or throttle setting.

Follow m0rie's advise with the plug as well. Use a brand new plug and if you have any used plugs toss 'em. They are evil and will cause you to get confused. Plugs are cheap anyway, so play it safe with a new one.

I don't know the gap for your plug, I have a 1999. Sorry.

Don't forget to post what you found out to be the problem Your final results can help someone else out someday!

this may be a bad question but what do you mean by jetting spot and how will the br8eg give me some boost thanks for the help i really just dont know this is the first time i have actually had to work on my own bike and i just dont know alot also do you know where i can get a manual for my bike without going to a dealer and paying $35.00 for one

i will go check now and let you know

Here's the plug gap info: .032" or 0.8mm , ebay probably has some manuals going for $10

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... eName=WD1V

This guys selling 1 for 1989-1994 all on cd in pdf.

http://cgi.ebay.com/ebaymotors/ws/eBayI ... ename=WDVW

thanks for the help all the lines are clear my main is a 158 and pilot 48 i also checked my reads to see if they were stuck but looks ok i will look at the ebay manual also thanks again so if all the lines are good and what not anything else i can look for

miteymike wrote:anything else i can look for

Some punctuation.

A question to the carb gurus.... Could this be caused by an incorrect float level ??

If a new plug takes care of the cutting out issue its time to look at your jetting. In most cases a 158 main and 48 pilot will be too rich and will at most foul the plug eventually, at least rob you of some power and throttle response. You can pick up a nice set of main and pilot jets along with a couple of needles for around $40-50. That will allow you zero in your jetting and unlock a lot more power and fun from your KDX.

-Maurice

Well thanks for the advice. I guess my next step will be a jetting kit. Do you know where is a good place to start as far as main and pilot jets go? Hopefully my punctuation is better, I have a tendency to leave it out when I'm in a hurry.

We need your ridding altitude! and my bike will act that way when i follow my kids on the small bikes for a while then open it up (I know my jetting isnt perfect yet but its getting there) and ill hold it there when it is missing a little after a second or two it will clear out and go. I havent managed to foul a plug yet but im trying hard. These guys are right new plug and lets get it jetted right.

The only thing I can add that hasn't exactly been covered is checking your gas cap (vent hole) and hose..... A little bit deeper check might be a visual inspection of the kips valves through the exuast port. I had the left one break and
it kinda freewheeled and acted strangely. Good luck.

I am riding around 1500-2000' for the most part were I ride the altitude changes pretty good depending on what trail you take also since I'm a newby at this how do i go about visually inspecting the kips valve I mean i see them on the bike at least the covers do i just take them off and look?

Gotta pull the pipe Mike. Then take a flashlight and look in there...there is one on each side.... Pull the little cover on the rear brake side of the motor that covers your actuating rod and manually move the KIPS rod back and forth while looking in the exhaust port. Look to make sure both are moving smoothly....

Clear as mud?

I'm going back to the fuel line not being full at all times. If it will not flow the fuel you got , or will have, a problem.

Gas vent line, dirt in "in-tank" screen, something caught in or plugging internal gas valve. I would pull the gas line at the carborator and route it into a container. Then turn on the gas valve and see how much fuel flows in 1 minute.

I would checkand clean the gas cap vent and line. Then with the top of the tank open (gas cap off) and the fuel level in the tank at least 4 inches down from the top of the neck; I would attach an air hose nozzle on LOW PRESSURE (~10psig) to the fuel line and turn the fuel valve to reserve. This will blow air into the tank causing the gas in the tank to bubble. (zip tie the hose to the fuel valve so it doesn't pop off.) If anything is caught in the in-tank screen this should free it from the screen releasing it into the fuel tank. Turn fuel valve off and remove the air line. Screw the gas cap back on and retest your fuel flow into a different can for a 1 minute period. Compare the amount of fuel collected pre verses post testing. If the amount is the same - I've just wasted 5 -10 minutes of your time. If your running a fuel filter - reverse flush the filter with fuel to unblock the filter media.

If the fuel flow is improved - you should drain your gas tank, remove the fuel valve; clean both components.

Hey thanks for the info I will have to try that after the 4th party thanks again and I will let you know how it goes.

Any update on this Mike?

Any chance you are using a non OEM fuel tank to carb hose? The OEM hose is molded, but I know some aftermarket fule hose can kink in the curved portions.

What groove on the needle is your clip?

You may want to try a WOT plug chop at some point in the testing.

Like m0rie said, I have had trouble with a 9 heat range plug. I use an 8.

The BR8EG is less likely to foul and requires less voltage to spark, I believe.