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Question about 2T air screw

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What's up guys I'm new to the forum, my name is James. I am not new to bikes in general I've ridden mx (mostly trail) since I was probably 8 years old. Anyway, for the last year or so I've been really into my quad and am just now getting back into bikes. I rode my buddies 450 four stroke Yami all summer long and decided to buy another bike. I just recently bought a 2001 KX250. It is in excellent condition with all original clean plastics and slightly under 50 hours total on it of easy ride time. It has a pro circuit expansion pipe with a FMF exhaust and is jetted to Pro Circuit/FMF specs. It also has VFORCE3 reeds. It has not had a top end yet but I will probably end up doing one over winter (still has great compression/power). To get to my question, I am wondering about adjusting my air screw. When I begin to let out on the clutch, it gets pretty quiet and through 1st gear, it seems rather hard to pull a wheelie, but it does not bog. If I am right in powerband, it is very easy in all gears, but riding the 450, I am used to being able to just rip on the gas have the front end come up. On my bike, it is like that in all other gears and the powerband hits hard and makes excellent power. Maybe I am just not use to the feel of a 2T. Do you think my air screw needs adjustment or could it be something else? Like I said, it is making excellent power, easy to start, great compression. Also, I am running Dumonde Tech 40:1 pre-mix with 91 octane fuel. Thanks for any input ahead of time. -James

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What's up guys I'm new to the forum, my name is James. I am not new to bikes in general I've ridden mx (mostly trail) since I was probably 8 years old. Anyway, for the last year or so I've been really into my quad and am just now getting back into bikes. I rode my buddies 450 four stroke Yami all summer long and decided to buy another bike. I just recently bought a 2001 KX250. It is in excellent condition with all original clean plastics and slightly under 50 hours total on it of easy ride time. It has a pro circuit expansion pipe with a FMF exhaust and is jetted to Pro Circuit/FMF specs. It also has VFORCE3 reeds. It has not had a top end yet but I will probably end up doing one over winter (still has great compression/power). To get to my question, I am wondering about adjusting my air screw. When I begin to let out on the clutch, it gets pretty quiet and through 1st gear, it seems rather hard to pull a wheelie, but it does not bog. If I am right in powerband, it is very easy in all gears, but riding the 450, I am used to being able to just rip on the gas have the front end come up. On my bike, it is like that in all other gears and the powerband hits hard and makes excellent power. Maybe I am just not use to the feel of a 2T. Do you think my air screw needs adjustment or could it be something else? Like I said, it is making excellent power, easy to start, great compression. Also, I am running Dumonde Tech 40:1 pre-mix with 91 octane fuel. Thanks for any input ahead of time. -James

You are describing a typical two-stroke power band: a substantial peak in power at the upper Rpms. This is normal. The air screw has no effect on power, just on how smoothly it runs.

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airscrew adjustments are usually 1-2 turns out from completely bottomed. i usually let bike warm up and idle then twist throttle moderately fast and see if rpms build quickly. the more the screw is out the leaner the mixture and vise versa. the opposite is true for 4 strokes. best indicater is plug color i like a light tan color.

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have you checked which main and pilot jet is in your bike and what about the needle which clip is it on. compare the settings to stock and go from there.

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