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KTM 250SX...my "powerband" is no where to be seen.

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Aside from the title, here's the real problem. It started a couple weeks ago at Budds Creek, my bike took a :) on me the first lap of practice. Came in, and it was leaking gas out of the float bowl. Figured that the float was stuck. Took it apart, cleaned it out, and bam. Same problem. Loaded the bike up and took it home, hoping to make it back to race the next day.

Got home, and took the main jet out and it was cracked. Not good. Ordered some new ones, and just re-installed the main yesterday. Adjusted the float height, fired it out and it started. Now it's EXTEMELY rich (haven't messed with any carb changes :worthy: ) and when I went to ride it, the powerband never kicked in. No matter how much I slipped the clutch or what gear I was in, it was always on the verge of it, but no cigar. Instead, it kept popping and sounded like the engine was about to blow.

Does anyone have any idea what could be causing this? Piston/rings? Float height? carb settings? ANYTHING?!?!??! :D

I'm getting a little fed up, just more irritated that I couldn't figure it out on my own. Any and all help would be much appreciated!!!!! :banghead: :banghead: :ride::banghead:

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Popping normally is a sign of too lean, but not if you saw all the smoke coming out you would say that. It feels like it's running with the choke on again... :)

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Hmm...

My brother experienced a similar problem with his 250SX. We were riding at a track with some quads at the same time. Well, he came up behind one and just stayed there for a while. No racing or anything, so he wasn't in a hurry to get around. The guy on the quad went really wide on a turn to let my brother by, but he got to high up on the berm and rolled, my brother hit him, and dented his pipe pretty bad. After that the bike ran just like you are describing. Figuring the dent was the problem, we pulled it out, but that didn't help.

After doing everything we could think, we eventually tore the engine apart only to find the power valve moved farther into the cylinder and it was hitting the piston. We still don't know how that happened though, the area around the exhaust port was just fine, no cracks or anything. From looking at it, there is no way the pipe could have pushed it back when he hit that quad. I'm still baffled about that one...:)

Although, since you were just recently working on your carb, that is probably where the problem is.

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Thanks Ud Luz!!! :)

So, does anyone know how to properly set the float bowl height?? :D

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Thanks Ud Luz!!! :)

So, does anyone know how to properly set the float bowl height?? :D

Check your manual. It's in there, I remember reading it in mine. People may give you some good tips on here, but to do it the right way, just read a little.

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I had a similar problem posted in a recent thread. I either had dirt in my carb or an over-oiled air filter. It made my bike smoke and I lost my powerband.

You likely have a different issue but I just wanted to point this out.

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Hey guys...just an update. The problem is fixed...turns out that there was not enough fuel getting into the float bowl, and thus it was lean when run WOT.

I set the float height and that fixed it, then I leaned out the pilot screw and finally got it to idle for more than 5 seconds!!! :D

Thanks to all the help guys!!!!!!!!!!!!!! It was MUCH APPRECIATED!!!!!!!!!!!!!!! :worthy::)

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