KDX250 missing power, bog problem

Matt90GT

Member
May 3, 2002
1,517
1
So I finally got out riding. Suspension and brakes were good.

The motor ended up being a bit of an issue. Here is what I know I have:

NGK br7es or SF405b plug
New FMF pipe
New FMF Turbine core II silencer
new FMF torque reeds
New unifilter
pk vent kit
42/165 , needle 2nd clip
Amsoil series 2000 mixed at 40:1

Basically the bike ran good when we got out there. But seemed to never get on the power band above 3rd gear. Then when you did get on the powerband it cut out above 3/4-7/8 throttle to WOT. Finally after about 5 mile of miserable riding (dont ask) the bike was like there was no power. Like a fouled plug. Changed the plug, made a difference for about 1 minute. Limped back to the truck. It was like there was something plugging the exhaust or riding with the choke on. Also the engine never got super warm, but we were not out riding that much. Friends kdx200 ran fine the whole time.

Here is my quick check:

Airbox is clean. Filter is spotless. Pipe is clear, but have not pulled it yet. Plugs looked good, good color and not really fouled. Adjusting the idle on the carb did nothing. Changed about 4 different plugs with all the same results. headlights still have lots of power.

Help?!? I know I need to tear into the bike in the morning to fix this. Here is what I am looking for: reeds, clogged carb, stuck power valve, blocked pipe.

Any other tips or hints appreciated! Thanks
 

Oregon Trail

~SPONSOR~
Aug 2, 1999
263
0
How many turns on the air screw? I think I run a 40 or 38 pilot with a 168 or 170 main (been a while, sorry) with the same exhaust but a Rad valve. What clip on the jet needle are you? Stock is a 42, 165 and 2nd groove. Are you running in the Funky Chicken Harescramble?
 

Matt90GT

Member
May 3, 2002
1,517
1
2nd clip.

I am not running any races. Just after getting all the bearings replaced and suspension setup and plastic, trying to get the engine running correctly.
 
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