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air screw pointless


farmerfred

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hi guys, im kinda stumped here, i've been tryin to tune my throttle response down low an get my idle correct but it appears my air screws are useless! meaning wether i turn them in tight, 1 an a half out, or basically take them out my bike runs the same, no change in idle or response, im runnin 290 mains, 4th groove down on needle an 30 pilots, im absolutley amazed an impressed with how it runs throughout entire rev range except for the inital 1/8th - 1/4 throttle, any ideas why my airscrews dont have any effect? thanks!

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hi guys, im kinda stumped here, i've been tryin to tune my throttle response down low an get my idle correct but it appears my air screws are useless! meaning wether i turn them in tight, 1 an a half out, or basically take them out my bike runs the same, no change in idle or response, im runnin 290 mains, 4th groove down on needle an 30 pilots, im absolutley amazed an impressed with how it runs throughout entire rev range except for the inital 1/8th - 1/4 throttle, any ideas why my airscrews dont have any effect? thanks!

 

I would guess that your Pilot Jet is too large, you might want to try a 27.5 or even the stock 25.

 

General rule of thumb:

If the air screw is less than 1-turn from Closed, it needs a larger Pilot Jet

If the air screw is more than 2.5-turns from Closed, it needs a smaller Pilot Jet

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im runnin 290 mains, 4th groove down on needle an 30 pilots, im absolutley amazed an impressed with how it runs throughout entire rev range except for the inital 1/8th - 1/4 throttle, any ideas why my airscrews dont have any effect? thanks!

 

Yeah, I'm pretty similar in set-up (check my sig.) but you dont say what elevation your at.

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this is just a guess, based on no info

 

but if your setup runs on a 290 main, then a 30 pilot sounds huge, even a 27.5 might be too big , it cant be worse than the 30 though

 

Ok, i'll try an give a little more info but i need to know what you need to know. i tried bumping my mains up to 310's today as i want it a little richer, i also dropped my pilots to 25's but now i have to keep them screwed in tight to keep it idiling, if i back them out even 1 turn my idle drops to nothing, 2turns an it just doesnt want to run period unless i pull the choke out just a hair, like i mentioned before,are these pilot circuits that touchy that i cant get a 30 or a 25 to run proper and i need a 27.5??? i feel the bike runs great from mid to topend, i just seem to be havin problems setting my idle and initial throttle response {hesitation/ bogginess}

 

In case it helps to solve the problem i do have the TORS still, but unhooked , also im trying to not use the set screws on top of the TORS to help set my idle as ive heard this isnt the proper procedure an it seems to effect the way the motor runs,{in a bad way}, should i be tryin to just use my air screws for idle adjustment or can i monkey with it up at the thumb throttle cable and on top of left TORS without worries??? sorry to ramble on, thanks again for your help and opinions

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Ok, i'll try an give a little more info but i need to know what you need to know. i tried bumping my mains up to 310's today as i want it a little richer, i also dropped my pilots to 25's but now i have to keep them screwed in tight to keep it idiling, if i back them out even 1 turn my idle drops to nothing, 2turns an it just doesnt want to run period unless i pull the choke out just a hair, like i mentioned before,are these pilot circuits that touchy that i cant get a 30 or a 25 to run proper and i need a 27.5??? i feel the bike runs great from mid to topend, i just seem to be havin problems setting my idle and initial throttle response {hesitation/ bogginess}

 

In case it helps to solve the problem i do have the TORS still, but unhooked , also im trying to not use the set screws on top of the TORS to help set my idle as ive heard this isnt the proper procedure an it seems to effect the way the motor runs,{in a bad way}, should i be tryin to just use my air screws for idle adjustment or can i monkey with it up at the thumb throttle cable and on top of left TORS without worries??? sorry to ramble on, thanks again for your help and opinions

 

Just in case... the TORS "brainbox" is the little black box w/ a 3-wire connector mounted on the upper-left front cross-member of the frame just under the front of the gas tank.

 

Regardless of the jet size you can't really adjust your idle by changing jets alone. With the Boyesen's, K&N's, and T6's you should probably be running the 27.5 pilots. Depending on your porting you may want to retard your timing back to +4 as well (retard = more top / advance = more bottom). You might have too much advance for a good idle; I doubt it but every bike's different and +4 is a great safe place to start.

 

Unfortunately if you're still rockin the TORS tops you're going to have to adjust the idle using the idle screws on the tops. The TORS tops are originally set at the factory and not very friendly to adjust but not impossible either.

 

The procedure goes something like this:

You need to lightly seat the Air Screws

Then back them out 2-turns

Warm-up the engine

Adjust the idle using the TORS Idle Speed Adjust Screws (to about 1500 rpm). You have to adjust them both equally as they directly affect carb sync. (If you have a sync tool this is the time to use it!)

Then you can adjust the Air Screws to fine tune your idle to low-end revs

 

If your pilot is right you should end up between 1 ~ 2-turns out on the Air Screws

When you're finished you should also have about a 1/4" of free play in the throttle cable

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