Help Ktm exc 125 2002 bogging lowend

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#1
Hey Guys, I own a Ktm Exc 125 2002 with keihin 38 pwk and is bogging lowend. if i roll on idle an open the throttle to fast ist bogs.
got new:
-topend 10h now
-new reeds
-new ignition coil
-new seals
- new exhaust packing
sorry for the bad english.
i just need help;)
 

RM_guy

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#2
Sounds like it might be lean. Have you played with the jetting at all?
 
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#3
yeah a bit
the mainjet is bit richer
needle clip is on pos.3 NOZG
and 48pilotjet (stock)
i tried the 58 pilotjet didt se any difference
 

RM_guy

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#6
Play with the air screw. All the way in is the richest and you don’t want to go out anymore than three turns. Don’t be afraid to go to the extremes, you won’t hurt anything by changing the air screw. Start with it like a quarter turn out see if it makes a difference and then go 2 turns out and see if it bogs. If you’re all the way in and it still bugs you probably need a bigger pilot jet.
 

RM_guy

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#8
Still sounds like it's lean. Did you do a pressure test to see if there are any air leaks? That would affect more than just on throttle roll off but should be checked.

You say you tried all of the carb settings but I highly suggest you read this thread on carb tuning by Eric Gorr. It's long but very complete and walks you through exactly how the carb works and how to tune it. If you have done the leak down test and did what Eric Gorr suggests and still have a problem, I'm afraid I can't help. It's kind of hard when I can't actually see the bike and how it runs.

Carburetor Tuning - Intro, By Eric Gorr
 

RM_guy

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#10
Good luck and let us know how you make out!