13' Yamaha 250F

dustin.olson.393
Edited Date/Time 8/1/2013 9:28am
Just bought a leftover 250f and just got it broke in and would like some input on this bog im having. I have a full FMF exhaust, Works connection Air Screw, and Boysen quickshot 3 with adjustable leak jet. Coming right out of corner it has the slightest hiccup. It responds great just sitting on the stand. But if I come out of a corner and get on it, it has the hiccup. or it does it when im just riding along and left off the gas and get back on it right away. Any help would be greatly appreciated.
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newmann
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newmann 7/31/2013 11:17am
7/31/2013 11:17am
Did it do any of this before the mods? Any jetting changes?
slipdog
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slipdog 7/31/2013 11:19am
7/31/2013 11:19am
Does that quickshot 3 have the hot start tied into it?
dustin.olson.393 7/31/2013 11:28am
7/31/2013 11:28am
I just started it and heat cycled it before the mods. It starts first kick, Great throttle response on the stand, Just the slightest hesitation when you get off the gas and then right back on it for a split second. Could it be from me letting off and then getting back on the gas so quick that the carb is getting to much gas? If so any ideas..? And as far as the hot start goes I am not quite sure. Its the quickshot 3...
slipdog
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slipdog 7/31/2013 11:42am
7/31/2013 11:42am
I just looked, the QuickStart is the one that combines the hotstart. Had a bike with one of those that wouldn't run right, bog and pop. Finally took it off and the bike ran fine with the stock acc pump cover.

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dustin.olson.393 7/31/2013 11:53am
7/31/2013 11:53am
slipdog wrote:
I just looked, the QuickStart is the one that combines the hotstart. Had a bike with one of those that wouldn't run right, bog and pop...
I just looked, the QuickStart is the one that combines the hotstart. Had a bike with one of those that wouldn't run right, bog and pop. Finally took it off and the bike ran fine with the stock acc pump cover.
Ok, I might give that a try tonight then. Should the stock jetting be fine for the midwest? Im located in southern Illinois.
RNagy052
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RNagy052 7/31/2013 12:00pm
7/31/2013 12:00pm
I have a 2012 YZ250F and it had a slight bog and also would want to cut off if you turned the choke off to soon after the first startup of the day (when cold).

Last year when I was at the Mini-O's I took it to the Pro Circuit tent, and bought a full exhaust from them. After they put the pipe on for me, and started it, they then went to work on the carb. They changed 3 jets, the main jet, the pilot and one other one (it wasn't the needle) and it made a night and day difference. No more bog, it didn't want to cut off when you turned the choke off right away, super crisp throttle response.It was like a whole different bike.

I have no idea what jet sizes they switched to, but I think they said the stock pilot was too rich.

Those Pro Cicuit guys at the big AM Events are squared away and very helpful.

Since you bought an FMF Pipe maybe you should call FMF up and ask for jetting recommendations based on your bike and their pipe combo, they should have something.
dustin.olson.393 7/31/2013 12:19pm
7/31/2013 12:19pm
RNagy052 wrote:
I have a 2012 YZ250F and it had a slight bog and also would want to cut off if you turned the choke off to soon...
I have a 2012 YZ250F and it had a slight bog and also would want to cut off if you turned the choke off to soon after the first startup of the day (when cold).

Last year when I was at the Mini-O's I took it to the Pro Circuit tent, and bought a full exhaust from them. After they put the pipe on for me, and started it, they then went to work on the carb. They changed 3 jets, the main jet, the pilot and one other one (it wasn't the needle) and it made a night and day difference. No more bog, it didn't want to cut off when you turned the choke off right away, super crisp throttle response.It was like a whole different bike.

I have no idea what jet sizes they switched to, but I think they said the stock pilot was too rich.

Those Pro Cicuit guys at the big AM Events are squared away and very helpful.

Since you bought an FMF Pipe maybe you should call FMF up and ask for jetting recommendations based on your bike and their pipe combo, they should have something.
Ok thanks alot man. You wouldnt by any chance have those jetting specs would you?
Josh422
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Josh422 7/31/2013 1:04pm
7/31/2013 1:04pm
Run a google search for FCR o ring mod...
TX24
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TX24 7/31/2013 1:06pm
7/31/2013 1:06pm
Have you tested with the leek jet adjusting it in or out a 1/2 turn at a time? I would also call PC or Boyseen and see where thay say to start.
jleews6
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jleews6 7/31/2013 2:25pm
7/31/2013 2:25pm
I just bought my son a 13 also and he loves it. He has had it bog a few times but its very rare. People talk like it does it all the time but we dont notice it that much. Check out this video Jason Raines did to fix this problem.
http://www.youtube.com/watch?v=HkRS9G-7yHc
bturner26x
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bturner26x 7/31/2013 3:31pm
7/31/2013 3:31pm
Most bikes are jetted rich out of the box. It depends on what part of the throttle you feel the bog/hes in. Each jet works for a different part of the throttle. 1/4, 1/2. 3/4, & WFO. May wanna adjust the leak jet since it controls how much fuel goes back into your bowl. The AP gives a squirt when you wack the throttle. Maybe try the AP mod too (O-ring mod). You wanna make sure gas is squirting into the head and not hitting anything in the carb when you hit the throttle. You can check this when the bike is on the stand, cut off, and air boot removed. I had the same issue on my crfs and my kxf. Its been a few years, but I'm pretty sure these were some of the steps I used and it was like night and day.
pete24
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pete24 7/31/2013 6:08pm
7/31/2013 6:08pm
put a 45 pilot in it set the fuel screw to 2-2 1/2 and run it, leave everything else alone
dustin.olson.393 7/31/2013 6:14pm
7/31/2013 6:14pm
Should I take off the quickshot with the adjustable leak jet then? Or leave that ??
TX24
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TX24 7/31/2013 7:05pm
7/31/2013 7:05pm
Leave it on.
dustin.olson.393 7/31/2013 7:08pm
7/31/2013 7:08pm
TX24 wrote:
Leave it on.
How many turns out should I be on the leak jet then?
TX24
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TX24 7/31/2013 7:44pm
7/31/2013 7:44pm
I would start by turning it out about a 1/4 or 1/2 turn and see what difference it makes.
dustin.olson.393 8/1/2013 9:21am
8/1/2013 9:21am
So I talked to Boysen today and they told me they think my problem is it being to rich. Because if i screw the leak jet in all the way it dies. They said if I cant tune it out with the leak jet that I should change the Pilot jet to make it more lean. Sound right? Because when you sit there and blip the throttle repeatedly it will just die out. Also when you come into the corner and rev it up to get the RPMs up it will bog a bit until you rev it like you have to clean it out. Any Help
dboivin
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dboivin 8/1/2013 9:28am
8/1/2013 9:28am
dustin.olson.393 wrote:
So I talked to Boysen today and they told me they think my problem is it being to rich. Because if i screw the leak jet...
So I talked to Boysen today and they told me they think my problem is it being to rich. Because if i screw the leak jet in all the way it dies. They said if I cant tune it out with the leak jet that I should change the Pilot jet to make it more lean. Sound right? Because when you sit there and blip the throttle repeatedly it will just die out. Also when you come into the corner and rev it up to get the RPMs up it will bog a bit until you rev it like you have to clean it out. Any Help
more info here.

http://www.thumpertalk.com/topic/1006193-2013-yz250f-bog/

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