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Yz250f 3/4 throttle sputter

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I have a 07 yz250f with a powerbomb header because the stock one broke, the pilot circuit seems good, I have a r and d fuelscrew so I tune it when the weather changes it. So if I whack the throttle in neutral it will hesitate the hit the limmiter. If I hold he throttle at like half way to 3/4 it sputters. I'm thinking its the clip position or the main. Idk and it also has a 45 leak jet I put In. What do you guys recommend

Edited by roostierooster855

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so the clip is still in the stock position?

is the mj still stock?

thanks for not following the forum faq in jetting info

and I looked there's not much useful info on there. I'm asking what my first step should be to mess with the needle or main jet. And is up or down richer on the l needle? I believe down is correct?

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so its clear that this was NOT useful:

 

7) when asking a question, please provide as much info as possible so everyone can help YOU easier. as an example, if you are asking questions about jetting please provide the air data (altitude, temp, humidity) and current jets used and the problem. in other situations please provide what type of riding/racing you do. this just makes it easier for everyone to help YOU.

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I'm guessing it's cooled off lately in Michigan, so I'd assume it needs to be richened up some. I'd start by going up on the main jet 1st. It's the easiest to do, just remove the 14mm cover on the bottom of the float bowl to access. A bigger main will allow more gas from 3/4 to full throttle. If you still want to adjust the needle, raising it (lowering the clip position) richens it.

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So if I whack the throttle in neutral it will hesitate the hit the limmiter. If I hold he throttle at like half way to 3/4 it sputters. I'm thinking its the clip position or the main.

.

Are you saying while in neutral and throttle held 3/4 open it sputters? If so, that's your rev limiter trying to keep you from blowing up the engine

Edited by oldnbold

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no its not the rev limmiter! and i put in a 182 main jet in tonight and i feel like it had more accurate throttle control, does not sputter as bad, but still with lots of flames somewhat it does still sputter. Which means still lean right ? should i lower the clip? seems like this fmf powerbomb header made the bike leaner. The bike was hot, i did a short run around the yard and revving for 15 mins and it was of course not as hot after a 20 min moto i would assume, but i could still judge weather it made it worse or better and it made it for sure better.

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IMO, the OEM needle on the 07 sucked. I had mine on the 2nd clip from the top and another TT'er in CA was running on the 1st. We both ended up using different needles, he an 08 OEM needle and me a JD Jet kit needle.

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I have an 07 and I was having the same issues. I put a 50 leak jet in and an 09 needle on the 4th clip position and it solved all of my bog issues. Plus it starts right up now. Couldn't be happier. I was going to put a 55 leak jet in but they only had a 50 in stock and ut works fine. All other jetting is stock and exhaust is stock.

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I have a 182 main, the needle is on 4th from top and the stock pilot jet with the fuel screw at 2 3/4 turns out. The difference is amazing. There's no bog or sputter and it runs really good and that FMF header really leaned the bike out

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