Dirt Bike Repair & Maintenance Forum

when im riding my bike if im in like first and just at idle, and i try to open the throttle up quite a bit, it hesitates and then goes, there is like a 1 second gap, i took the carb apart cleaned it, adjusted the air mixture screw, air filter is clean!!,  i have an 2006 rmz-250,  any ideas??  
2006 RM-Z250

well all i know is 4 strokes arent able to..... be idling (while giving it no gas) and then opening up the throttle ALOT, without hesitation.

Im probubly not helping at all but.oh well  
When the power of love overcomes the love of power; the world will know peace

how'd you go about adjusting the airscrew? it might be adjusted wrong. ~pat  
PEACE GUYS ITS BEEN A BLAST!!!!! ~patrick

i set it to specs 2 1/4 i tried doing the turn it in until stall turn it out until it reaches peek rpm, but when it reached peak rmp it was at 3 1/4 and it seemed a little much and it still didnt solve the hesitation, so i put it back to specs  
2006 RM-Z250

you will always have this problem. 3 1/4 turns is too much. get the next smaller pilot jet and set it to peak rpm. why are you doing this anyways. if your doing holeshots or drags this is the wrong way.  
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Ride 2 strokes, buy 2 strokes, save the 2 stroke.

1998 cr125
2002 cr80

My guess is that it could be your jets, check your stock settings, and see what jets you have in your bike. It sounds like you might be running a little rich. Are you riding at a high altitude?  
I LOVE to fly.... over the handlebars.

im in canada british columbia, and its not a high altitude here, the jets are stock, everything is stock, exept the fuel mixture screw i put in its a pro-circut, but i was having this prob before i switched anyway, maybe it just doesnt like going from idle to high rpm very fast i can see why it would do it, too much air at once, and theres no way the fuel can spray that much in  and when it does catch up a second later its got enough fuel, i wonder, accelerator pump??? not sure tho,this is my first bike not sure if other 4 strokes do this aswell  
2006 RM-Z250

You have your choke off when you do that right?
sometimes my bike (CRF230) does that when it's cold or my choke is on when I am warming the engine up.  
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It takes a real man to say a 230 is a nice bike - Will12546

lol, my choke is off :P  
2006 RM-Z250

Do what elk said. Problem solved.  
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Ruff!

well i got it running pretty decent now, i dont wanna rip apart the carb and change the main jet, so i played around with the fuel mixture screw a bit more and got it to 2 3/4 turns and it runs pretty decent now,  
2006 RM-Z250

Cool, And elk said your pilot jet not main, Because you were 3+ turns out.
And i agree. You were to far out for the weather ect...  Now if you end up that far out again to fix the just go to a smaller pilot jet and you will beable to adjust easly withing the proper range As the pilot jet and air/fuel screw work together.  
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Ruff!

I know its a little late to reply, but as i've said before, when u open the throttle really fast, airflow speeds up much quicker than fuel, thus explaining why the pilot jet is there, but usually when this happenes just tinker with the pilot jet or air jet, and you should be fine.  
The best source of protein is Raw Eggs~!

Actually, don't do what Elk says. He and YZWoods are two-stroke guys, and they forgot that the four-stroke has a fuel screw and not an air screw. A hesitation is a lean condition, and going out on the fuel screw richens the jetting. If you can get a good result at less than three turns, you should be good to go. When you have the crew out that far, the spring pressure holding the screw in can be very light. Check the screw often to make sure it doesn't fall out. If you need more than three turns, then you need a larger pilot jet. Not a smaller one. And the board is right, with a four-stroke, you shouldn't just wack the throttle open. Try turning the throttle slowly.  

going from a #40 pilot jet to a #42 pilot jet, is that richening it up?  
2006 RM-Z250