Posts
47
Joined
1/19/2024
Location
Chicago, IL, USA
I have a 2003 ktm 125 SX, I jetted the bike to factory specifications for the weather, 16 degrees right now, bikes top end is brand new, just broken in. Rejetted for the weather, and the bike idles for years, but if I’m in 2nd gear, from a stop, just before power-band, and womp on it, the bike stutters, won’t accelerate for a few seconds, and then after 2 seconds of struggling, it goes into band and works perfect for 2-3 minutes, before repeating. Bike has adjustable PV, and a pro-circuit silencer, repacked last month, any ideas on what’s causing the bog?
What exactly are the factory specifications for the weather? What elevation are you riding at?
I’m at sea kevel
KEIHIN PWK 39 JETTING SPECS -2 to 19 degrees F
Main, 195
idle, 55
Air screw, 1/2 turn from fully seated
needle clip, 5
Needle, R1468D
This is the guide in my manual.
Did you check the float level to see if it's in spec? I think this could be a symptom of the big 39mm carb as well. Might want to try a richer needle since you're on the 5th clip position.
New top end, do you have an air leak?
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Float is in spec. Right in the middle. New top end has 0 leak down, and no bubbles when I spray water around gaskets. The 39 is overkill for a small bore stroker, but she runs good other than the bog right before power. Maybe I have it adjusted improperly?
From the specs that you have listed, jetting wise, it sure looks rich enough to me from that aspect. That 1468D needle in clip #5 is damn rich. Is this with a #6 slide as well ?
Hah, bike ran great and crips in the negatives everywhere except the bog, stock slide I believe, although it is a 03 so people probably changed it. Bought the bike last year, first race machine in 3 years. Thought it’d be cheap and easy on parts too, bike lives up to expectations except the bog. Power valve adjuster is set up “decently” close to the LANGSTON setting. This is one of the few times I jet my bikes, usually just put it up for winter. I’m not very experienced with Ktms. But I do love this bike, and would love to solve the issues. And thank you for responding, I was hoping you’d see this.
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