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Some Suggestion Jetting?


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Well I want to get my banshee re-jetted.

 

Before I was running 320's with K&N filter and FMF pipes no air lid

 

Now I have advanced my timing 4 degrees, Recieved some nice porting (REALLY opened it up and added some extra ports) and changed the head to 20CC domes from the stock head...

 

Jets are $5 each around hee and they won't let me return the unused ones. I was planning on just bying a bunch and and trying them out but for that price, its almsot cheaer to have someone dyno tune my banshee.

 

The local shop says not to change the stock pilot jet still, and that my jets will be no larger than 330's even after those mods....

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Hey Justin, who's doing the porting? They should be able to get you in the ballpark...but the coolhead should not require any jetting change, and the degree key at most will want one size larger on the mains, that just leaves the porting, which could be anywhere from the same jetting you have now to a few sizes larger...

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PassionRE told me to start with 35's and work my way down and also to change the pilot jet one size up from stock...

 

But thats $50 worth of jets :(

 

I could have it dyno tuned for like $125...

 

I read that whole article, and acording to it my banshee should be lean but instead it runs very rich...It was rich before...I dunno what to do and I don't want to spend a boatload of money on little itty bitty jets

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I stopped by SamCo and I got 2 free toomy needels (i didn't want to buy the kit because im changing carbs soon), He told me with porting the stock needels really are not very good.

 

SamCo seemed to think 320 would run rich in combination with the toomy needels and he told me the piolts are fine unless I have to adjust the screw for more than 3 turns out. He suggested I jsut use the 320's and if they are too rich I could go down to 310's or 300's but he thinks it might be perfectly fine with the 320's

 

Does this sound right? He told me to install the needles on the 4th position from the top.

 

Also one of the needels has a point on the end and the other is rounded, they are also a slightly different color. Taper length and clip spacing is all exactly the same. They were jsut spares he had laying around I guess.

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I would think he'd know what he's talking about, but if you doubt him, then do a plug check and adjust the air screws and try different needle positions... Trial and error, thats how you find what YOUR shee likes...

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I would think he'd know what he's talking about, but if you doubt him, then do a plug check and adjust the air screws and try different needle positions... Trial and error, thats how you find what YOUR shee likes...

I agree but the closest place to go testing is about a 2 hour drive away so i wanted to make sure its fairly accurate before I go out. I don't think the cops would like it if I was pinning 6th down my 25MPH street. Heh, thanks again.

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I would think he'd know what he's talking about, but if you doubt him, then do a plug check and adjust the air screws and try different needle positions... Trial and error, thats how you find what YOUR shee likes...

I agree but the closest place to go testing is about a 2 hour drive away so i wanted to make sure its fairly accurate before I go out. I don't think the cops would like it if I was pinning 6th down my 25MPH street. Heh, thanks again.

2 hours!!! damn...Bring the jets w/ you and find a testing area. Spend a day and jet it in. You only have to do it once, then you can enjoy the performance every ride after....

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You ditched the TORS already, right? To sync the carbs you just need to adjust the adjusters on the carb tops so that both slides move off idle at the same time (don't sync them with the idle screws)...if you have TORS then you do sync them with the knobs so both open at the same time, but then you may need to adjust them both the same amount to get your idle speed.

 

If it was me, I'd start with what PassionRE suggested and work down, but as Banchetta said you really need to find a place to dial it in right. I have 350, 340, 330, 320, 310, hell all of 'em down to 190, I'm at 370's now and if anything will need to go larger for the cold weather...if you want I can ship you the jets to dial it in and you can just buy the ones you need and send 'em back. Lemme know.

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You ditched the TORS already, right?  To sync the carbs you just need to adjust the adjusters on the carb tops so that both slides move off idle at the same time (don't sync them with the idle screws)...if you have TORS then you do sync them with the knobs so both open at the same time, but then you may need to adjust them both the same amount to get your idle speed.

 

If it was me, I'd start with what PassionRE suggested and work down, but as Banchetta said you really need to find a place to dial it in right.  I have 350, 340, 330, 320, 310, hell all of 'em down to 190, I'm at 370's now and if anything will need to go larger for the cold weather...if you want I can ship you the jets to dial it in and you can just buy the ones you need and send 'em back.  Lemme know.

that would be sweet but I need to get it done by this weekend im not sure they would ship ontime? I put in the new needles and I have a feeling they will be just about right (might need a new pilot jet) I do still have the TORS and don't plan on ditching it untill I buy new carbs this summer. How far open aprox should the slides be in the idle position? or should they be compleatly closed? I can sync them after that np.

 

I got teh carbs back on with the new needles that make it run richer, and I was already rich before im hoping it is close to about right. I have to wait till I get home this afternoon to fire it up for the first time because it was 12:00 by the time i was finished last night. The TORS and carb boots are fucking annoying as hell! Luckily I should not have to compleatly remove the carb to jet it here on out. 370's are HUGE! SamCo said the most they normaly use is a 300-310 from the results of their dynos on a ported bike, Alba and motoworld told me the same thing. But all 3 of these places use aftermarket needles I beleive (not positive about motoworld)

 

I think ill throw my near new plugs in for break in then ill toss new ones in and take the readings. After I drive it a little I think ill have a feel for needing o go up or down and ill buy a couple sizes in either direction. but I may need to change the pilots first anyways...

 

Man this is a pain inthe ass :blink:

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If it has a bog or hesitation right off idle, and adjusting the airscrews doesn't cure it...if going out on the airscrews helps but the problem persists after you go out past 3 turns, try the next size smaller pilot and start over with the airscrews 1.5 turns out; if going in helps but it still bogs when you get to a half turn out, try the next larger pilot. If the motor is fresh, start the breakin with new plugs, after you get to where it's idling about 15 minutes, see what the plugs look like; if the center electrode and the base ring have no color chances are they are lean; if dark and wet they're rich; light brown is perfect.

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If it has a bog or hesitation right off idle, and adjusting the airscrews doesn't cure it...if going out on the airscrews helps but the problem persists after you go out past 3 turns, try the next size smaller pilot and start over with the airscrews 1.5 turns out; if going in helps but it still bogs when you get to a half turn out, try the next larger pilot.  If the motor is fresh, start the breakin with new plugs, after you get to where it's idling about 15 minutes, see what the plugs look like; if the center electrode and the base ring have no color chances are they are lean; if dark and wet they're rich; light brown is perfect.

Ok. The plugs I have in it are almost new but have been run, When I get home tonight Ill toss in a new set of plugs and let it idle for 15 min and ill take a look. I know I won't need to go down a size cause I don't know how to get them smaller than stock :)

 

thanks again Ben, that jetting article is great, I printed it out and it now has a home next to that free manual that was floating around :)

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