98 kx250 issues

[blackkx]

 i have a 98 kx250 its a great bike and i love the power (most of the time) but have a problem that is completely stumping me .

I was riding on my practice track today and noticed the bike trying to bogg coming out of berms , the thing that gets me is some times it boggs and sometimes it blast through like its fine I recently replaced the carb boot due to an air leak problem i had , so when it started doing this i automatically checked to make sure that my crank seals where fine ,ign side is dry and clean, an i am not burning my crankcase oil so that shouldnt be the problem . the silencer has been repacked , new airfilter , gas cap all in the last 3 months or so .

It being intermittent is whats baffleing me , anybody with any knowledge of this machine please help me , i live to ride and this is irrittating . 

[blackkx]

btw when the carb boot was replaced the carb was taken apart and cleaned including making sure all the jets were free of cloggs .

[FuriouSly]

Howdy..  check the float bowl height.  Replace the fuel filter if you have one.  Jetting or hotter plug for MX.

Sly

[blackkx]

 I run a br8es plug ,how would i check the float level or adjust for that matter , i dont now a whole lot about carbs , this bike is the first i have had to mess with  carb wise , i beleive i am capable just not 100 percent sure.

[gowen]

http://justkdx.dirtrider.net/floatlevel.html

I agree with the carb float, though is it like bogging like cutting out or just out of power? How does your plug look? Black? White? Grey? Brown?

[blackkx]

 It cuts out briefly sometimes and i can feather my way out it with the clutch most of the time , i noticed when i go into the berm in the same gear but going faster (engine reving higher) it blasts right through . other times i stop and rev the bike and it will bog a little and rev up run like crap and then just snap out of it and run fine . the plug was a beige to brown colour when i purchased the bike (about 6 months ago) and was running maxima castor927 , but everyone local told me it wasent good for kawasaki powervalve as far as gumming it up ,so i switched to pro-honda hp2 then shortly after i had a carb boot leak but it took me a while to diag that problem so i took the carb apart first and cleaned everything very thouroughly and made sure the jets were free of debris or trash and put it back together however i did fiddle with 2 screws on the side of the carb and dont know if they are in correct adjustment , the one on the side of the float bowl i bottomed out and then backed out 1 1/2 turns . (as told by friend)

But  the one on the side of the carb it self could be out of whack anyway my plugs now look darker kinda black actually but i change them like crazy because they are cheap . this is so frusterating .

[blackkx]

  just rode it today for about 5 or 6 laps and it ran great , pulled hard out of all the berms and never let me down , i really dont understand whats going on here .

[01KX5WOODSRIDER]

    One more thing to check is gas cap vent. This can cause
intermittent lean running from fuel starvation.

[gowen]

Your jetting can have alot to do with the humidity and weather too. I'd still try to give the float level a shot. Read the link I posted and check. It sounds like you are running very rich and that would cause poor wide open throttle in a berm.

Also, try running a semi-smooth line  (not much RPM) and then clutch a wide open throttle (as if coming through a berm) and see if you get a the same bogging.

I don't think the berms have much to do with it, just going from slow to fast and alot of gas is the issue..?

[blackkx]

 yea i dont thinks its berms either because it would do it riding in a strait line aswell , now that i think more about it right after i fixed the carb boot i was riding with some friends part of the ride is a limerock road and we started drag racing , me being the only kx of the bunch left em all in the dust until when i revved it high at the end of 5th and it started bogging out then but that was the only time it happen that day so i didnt think much about it till now . i didnt get a chance to ride the bike today , i had no daylight left by the time i got home .

[01KX5WOODSRIDER]

   My KX-250 started running lean when the piston and rings
got a little worn. A compression tester is a easy way to check
this.

[blackkx]

 i do need to check the compression , actually i planned on putting a new topend in it in about a month , but i should check it , does anyone knw what the compression should be on my bike . i dont know if this rules any thing out but i will add that the bike starts on the 1st kick 9.5 out of 10 times , very reliable even in its current state .

[blackkx]

 well i finally had some daylight after work so i fired up the kx and rode the sh#t out of it for about a halfanhour and no bogging at all , the last 3 times i have riden it , no bogging , the bike runs great but it is turning plugs black, not wet , just black .


the bike pulled hard evry time i needed it to , i geuss it fixed itself

btw a quik little story ; this guy down the street has an 85 kx500 , his friend dave was visiting and we got into a kawi vs honda arguement , dave has a 01 cr500 , long story short it came down to a drag race and that 85 kx 500 wasnt being touched . i rode both bikes (first time i have ever ridden a 500) all i can say is wow both bike were insane fast as far as i am concerned , definatly partial to the green one , i am impressed , and i now want one 

[kxaddicted]

which one handled better? im thinkin kx500 myself.
i have the same bike but no carb problems just that it floods plugs and wont start lol until i turned the gas on. DUH i know. the forks r leakin tho and causes the front break to be crap... needs the little seals replaced...

[Hillclimb#42]

well i finally had some daylight after work so i fired up the kx and rode the sh#t out of it for about a halfanhour and no bogging at all , the last 3 times i have riden it , no bogging , the bike runs great but it is turning plugs black, not wet , just black .


the bike pulled hard evry time i needed it to , i geuss it fixed itself

Plug should be carmel brown. Black is rich. Turn the mixture screw another half turn out. Left is lean and right is rich. White or green is too lean, while black is too fat. If you run the crap out of it always you can run a light ratio of like 50:1. I use synthetic two-stroke oil (super techniplate). If it needs a top-end, it will bog easier than a fresh motor, and still be easy to start.
 Weather plays a part. Probably runs better during cool conditions. Don't be afraid of tweaking mixture screws. Check out jetting chart on here to see your jets are right for your elevation and temperatures. Ride it hard, go back to the truck pull the plug and adjust mixture until plug is brown.
  Ratio of oil, fuel octane, jetting, float setting and clip position should be set and left alone. You can tweak it with the mixture screw, plug, and gearing.