250F Hesitation off idle

[josmoloco]

07kx250f, jd jet kit with settings for under 4k feet for mx, carb very clean.
Bike cranks easy. Runs very well. If I just crank it hard of idle it sputters and hesitates.

Would I be looking to adjust needle position? Fuel screw doesn't seem to be cutting it.

 

[snowflake]

sounds like its time to load it up on a trailer and take it to the scrap yard.

 

[SRAD97750]

Is that an FCR carburetor? Does it have an accelerator pump circuit? -BIG DAN

 

[josmoloco]

Yes it does

 

[SRAD97750]

There are a couple 'free' mods to counteract the bog off idle with these carbs.
One is to add a small rubber band to the accelerator pump arm.
The other is to install the smallest leak jet available, or plug it off completely.

http://www.thumpertalk.com/wiki/_/the-o-ring-mod-for-an-fcr-r325
-BIG DAN

 

[josmoloco]

I have the rubber band

 

[timoyz]

First, make sure the AP is timed correctly, before you do anything else.

 

[josmoloco]

First, make sure the AP is timed correctly, before you do anything else.

Tutorials I assume online

 

[SRAD97750]

yeah, you're supposed to set it so the stream just misses the slide as it rises. Which can be tested off the bike. -BIG DAN

 

[ossagp]

does it do it all the time or just when hot or just when cold?

 

[josmoloco]

All the time

 

[timoyz]

Tutorials I assume online

Easiest way is to take off the subframe so you can see the back of the carb. When you grab a handful of throttle, the squirt should just miss the slide, and shoot into the intake. If it hits the slide, adjust it, if there is no squirt, clean it, and inspect why.

 

[ossagp]

I like Timo's plan.

 

[ossagp]

All the time

If it is an all the time thing, I am betting with Timo and the rest on the AP. If you were green I would suggest that you may be expecting too much, but I think you know what is realistic for a small highly tuned engine.

 

[josmoloco]

Will have to check that out. It's kinda acting like my non pumper I have on my xr