Rejet bike now Hesitates a little when throttle blip?

Just picked up a 2003 crf230. Replaced the main jet with a 120, pilot jet with a 45. Left the stock needle in and at the stock setting (3rd position from top), 1 3/4 turn out on the fuel screw. I removed exhaust baffle and removed the "snorkel" from the air box. Starts right up with no choke and idles like a champ. If I slowly give it gas I have nice throttle response. Problem I am having is when is crank the throttle from idle it bogs and wants to die until I return the throttle back to home? Do I have the fuel screw turned to far out or should I turn it in more? For my elevation I matched my jetting to someone close to me, they recommended 1.5 -2 turns out on the fuel screw. I did not change the needle to the fourth position. Can you guys help me out? Carb is built correctly. Not sure if this is a fuel screw or needle issue? Like I said it runs great until I try to crank it from idle. Every where else in the range is great! First bike and not sure what to do.....thanks guys.

Edited by johnston.jer

Can you tell us what elevation and temp you are riding at?

Absolutely, Michigan west side, 500 feet above sea level and currently 60-70 degrees.

I ride between 4000 to 8500.

My settings are 115m -45pilot. My 2009 didn't have an adjustable needle... From the recommendations I read, I purchased a 2003 to 2005 needle. I put the clip 4th slot down.

I did have a 42 stock pilot, going to a richer 45 pilot was a big help along with the needle.

My bike runs great and in the winter I move to a 118 main.

Your main and pilot seem pretty close. I would try moving your needle down, a lean condition can cause bogging.

If that doesn't help, I would try a 48 pilot at your elevation.

Also get on the bike and run it hard and let off the throttle. Do you get any backfire at all? Popping or backfire, your lean. Adjust your fuel screw to allow more fuel.

I think overall your settings for main and pilot at your elevation would be 85 degrees and up, summer settings. Now that it's cooling down look at the clip and possibly pilot and might need to go up one in the main also.

Thanks guy's I will try to drop the clip to 4 and see what happens.  I am going riding tomorrow so I will get a feel of real world conditions too

You must also consider the carb has no accelerator pump. Therefore yanking her wide open in neutral she might tend to sputter. Does it do this while riding?

You must also consider the carb has no accelerator pump. Therefore yanking her wide open in neutral she might tend to sputter. Does it do this while riding?

That's what I was waiting to hear. I can shut my bike off with the throttle if I tried to, with no load on it and whacking the throttle wide open. Like Confederate said the carb has no accelerator pump circuit, so sputtering and popping when whacking the throttle wide open sitting still/in neutral is normal. If the symptom occurs while under load then you may need to rejet. Trying to jet the carb for no load throttle response is pointless.


Edited by Tech25

Great, learning things everyday. Thank, will report back with results after riding today

This is my first 4-stroke bike, trying to figure out how things work lol. Lots of things different from my old rm250 I had years ago.

For those who care, I ride in Michigan, 250-1000 ft above sea level. I removed the exhaust baffle, intake "snorkel", installed a 120 main jet, a 45 pilot, left the stock needle in stock position (3rd from top), and am at 2.25 turns out on the fuel screw. WOW, all I have to say. Thanks for the advice on this thread everyone. Great advice to not tune on the stand in the garage lol. Took it out today and after warm up turned fuel screw out from 1.75 to 2.25 and all hesitation was gone. Wheelies in second, lots of power through every gear! It was 65 here today. Super happy!

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