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New '09 YZ250F hard to start

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Just bought my 14 year old a new '09 YZ250F and the only way it will start is with the choke off. If I choke it and go to kicking it floods and gas runs out of the carb. The temp is around 55 or 60. Once its warmed up it cranks just fine with the hot start. I've got a '06 WR450 and it has to be choked to crank if its the least bit cool. Any ideas?

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Are you opening the throttle when you kick it? I have found they will usually start with no throttle at all. Cold: choke on, 3 to 5 kicks, start. If they are being stubborn one full twist of the throttle then start kicking, once again 1 to 4 kicks after that it will start running. +/- a few kicks depending on temp, etc... I never use more throttle than that to start it cold.

I'm assuming you have made no adjustments to the carb. Do you turn the fuel off between rides? Has the bike been sitting a long time with fuel in the carb? In other words, could something be gummed up?

Best of luck!

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Nope, no throttle at all. I've got a WR450 and had a YZ450 so I know the routine about no throttle while kicking. If you choke it and start kicking it floods. Last night I got on it and kicked it without the choke and it fired right up and just for kicks I pulled the choke out a couple of seconds after it cranked and it died. Ususally they idle faster with the choke on unless its already warmed up. The thing I notice different about his 250 and my 450 is his bike seems to warm up instantly. The minute you crank it you can take off. My 450 runs like crap if you fire it up and take off on it cold.

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When i first got my 08 I had a hell of a tim egetting it started. Eventually it just seemed to get better as it got broken in a little more.

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Well, my son went out this morning, temp about 45 and kicked it about 20 times with the choke and nothing. He sat there a minute, turned the choke off, pulled in the hot start and it fired right up. What the hell! No choke, 45 degrees, and hot start and it fires up. Could it be to rich? Maybe I need to turn the fuel screw in or go smaller on the main. When he first got his 85 I could hardly get it to crank and when it did it would foul the plug in a matter of minutes. I changed out the main and went with a hotter plug and that cured it. The same plug has been in there for over 2 years.

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I think I solved the problem. I ran the fuel screw in and it was about 2 1/2 turns out. I ran it in to about 1 1/2 turns out and now it will crank alot easier and with the choke when its cold.

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I think I solved the problem. I ran the fuel screw in and it was about 2 1/2 turns out. I ran it in to about 1 1/2 turns out and now it will crank alot easier and with the choke when its cold.

:banana:

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I've had this happen a few times on my 09, it was almost like something was stuck in the carb. After I got it going it was fine. I swear it happened after some back pressure into the carb for whatever reason.

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Thats one thing that drives me nuts about 4 strokes, everyone is different when it comes to starting. I had a 04 YZ450, my first thumper, and I fouled about 6 plugs before I figured it out. Then I went to my WR450 and had to figure it out, of course the plug fouling was over with.

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Thats one thing that drives me nuts about 4 strokes, everyone is different when it comes to starting. I had a 04 YZ450, my first thumper, and I fouled about 6 plugs before I figured it out. Then I went to my WR450 and had to figure it out, of course the plug fouling was over with.

I would do a cold start, pull the choke, kick it and here a small blurp like it was going to fire on the first kick, but wouldn't. I would turn the choke off and kick it 30 times and it would start. Let the bike sit some more, pull the choke out and everything is fine. I've had the bike for almost a year now and it does it every couple months. Once I get it going it's fine.

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