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Wow... I Still Can't Get This Jettting Thing Down...

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Okay, so basically I own the 250X (CA model), I've done all the CCC mods except the cams, and put a baja designs air smog pump block off kit. Bike runs like a dream - with a catch. HORRIBLE bog just seems to rip me to pieces. I can't tell if it's the leak jet, main jet, or something like an air leak. Here's what I've done so far:

Leak Jets - Gone from stock 65 to 70 - ran horrible

Changed from 70 to 55 - runs little better, but still irritating

Main Jets - Started with 155 bike runs great past the bog

Changed from 155 to 152 then 150 - bike still runs strong on every jet

Now - running a 152 jet (as Honda recommends)

Pilot Jets - Swapped from a 40 to 42

Needle - Bought NCYR needle - played with it and to no avail yet

Now its in 3rd position (from top)

Airbox - Cut to Honda's specifications, stock a/f wit b/f screen

No LUCK whatsoever with the bog. I'm kinda running out of ideas - I'd hate to give in and take it to the dealers. The bike rips once I get out of the lower RPMS... Anyone have any suggestions? I appreciate it, thanks!

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Where is the bog? Off idle? or when you get on it from mid to WFO?

-Fiddler

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sounds like not enough fuel being squirted in the accelerator circuit as you noticed by changing the leak jet---I believe the smaller the leak jet the more fuel will be squirted into the venturi--leak jet returns fuel to bowl so smaller= richer.

This is my interpretation by reading up in the manuals as I am making the transition from 2 stroke tuning to 4 stroke so please get a second opinion ---hopefully from Dr. J.D. himself

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Crazyman, you didn’t mention adjusting the fuel screw. It’s on the front bottom of the carb. From what I’ve read here it has a lot to do with the pilot jet which where the bottom end is delivered from. The only thing is the stock fuel screw is almost impossible to adjust with out rotating the carb. I’m waiting on my ZIP TY adjustment screw from TT. To fine tune mine.

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You know, that could be the next thing to try - I really didn't think it had that much to do with it because I hadn't heard it mentioned much before - thanks anyways! I'll let you know some results!

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If the bog occurs with a quick blip ot the throttle, the leak jet and pump timing needs set for sure. By all means, only change one jet at a time. If no fix, put it back and try elsewhere. That way at least you know what fixed it. You can get a 55 leak jet from any bike with a fcr carb. Incidentally, what exhaust is on this critter?

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