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Cheetah 485 jetting help


smoker

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Hi guys,

 

Ive just got a 485 cheetah with 39 pwks,,,and need some help to get jetting in the ball park,

 

im at 600ft above sea level and the carbs have cel needles,temps are 25c-30+c and am running 27cc domes (cpi not trinity) and shearer bb oof dragpipes.

 

any help would be greatly appreciated.

 

 

 

Thanks guys

 

keep on smoking

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there are..

 

with pwk's id start at 55 pilot and 180 main and work from there.

 

bet your in the range of 40-48ish and 165-200 on the main.

 

Thanks Cam

 

played with jetting all day yesterday,,,im down to a 158 main and 40 pilot problem is it sputters at 1/4 throttle (rich) once past that it wants to rip my arms off yeeehaaaa.

 

i tried lowering the needle one notch and the sputter was gone but then after 1/4 throttle it was running lean bwaaaaaaah.

 

is there a better needle than the cel to fix my problem? or any other advice

 

thank you

Edited by smoker
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my 485 on alky with 41/44 lectrons and a +6 was nearly impossible to ride in the trails..

 

try richening up to a 42 pilot and then play with the needle if that dosent work well check out sudco's site and read the section on needle tapers and cuts and you may like to order a few differnt needles if you change needles you may have to start your jetting process all over again. but i wouldnt be afraid to play with needle size as its not really a common motor..

 

be carefull with top end temps as they can rip on top but lean down and run hotter dome temps. either an added PJ for a small amount of fuel enrichment at longer runs OR jet a tad richer on the main.

 

keep playing with it you will get it figured out.

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my 485 on alky with 41/44 lectrons and a +6 was nearly impossible to ride in the trails..

 

try richening up to a 42 pilot and then play with the needle if that dosent work well check out sudco's site and read the section on needle tapers and cuts and you may like to order a few differnt needles if you change needles you may have to start your jetting process all over again. but i wouldnt be afraid to play with needle size as its not really a common motor..

 

be carefull with top end temps as they can rip on top but lean down and run hotter dome temps. either an added PJ for a small amount of fuel enrichment at longer runs OR jet a tad richer on the main.

 

keep playing with it you will get it figured out.

 

 

Thanks again Cam,

 

I will keep playing with the jetting,,,the cel needle seems the most popular so hopefully i can get the jetting sorted without changing needles,and having to start all over again.

 

What needles have you used in the pwk's ? also what cc domes do you run. if you dont mind me asking.

 

Thanks.

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talk to windycityjohn, hes pretty good with cheetahs. not many ppl have the 485, i do but i never dialed in the jetting. john can tell u all the members with cheetahs

 

 

Thanks Nick. I'd chime in with info, but I ran the 35PWK's and the signal strength thru those is a lot stronger, so they pull more fuel thru the jet. So my jetting info would be off the mark for 39's.

But for what it's worth......I was at 35 pilots and 148 mains.

 

But (As I've said enough times that they finally just deleated all my posts) unless he gets his domes custom cut and get's the "Trinity Fingerprints" out of that motor.....no mater what he runs for jets....he's still going to blow O-rings and destroy pistons till the end of time.

(I know I told you that one ahead of time on your motor. Right Nick? What's your status? Do you have your new pistons and Nikasil yet?)

 

So correct jetting will get it running. :unsure: But only long enough for it to destroy it's self. banghead

 

I know CAMATV loves his 485....but the only thing that Cam's motor has in common with Smoker's .....is the cc's. ;)

(And Cam has VERY custom domes!) :drool:

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On a drag bike on gas, I would just run it a bit rich on the pilot to make up for the needle if you have to. Definately throw trinity's domes in the trash and have someone else cut you some. CPI big bores like higher compression BTW. You could also adjust the timing till you get it where it will jet easy. There should be a motors happy spot where it runs right dont be afraid to go less or more 6 or even 12 degrees. Sometimes they are happy with more or less. Cams 485 likes timing. Hope I'm not giving any of your secrets out Cam.

On most motors with 39 pwks on gas 165-180 gets it with a cel needle and about a 48 pilot So I would start in the 190 or 200 range and go down as needed.

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  • 7 months later...

On a drag bike on gas, I would just run it a bit rich on the pilot to make up for the needle if you have to. Definately throw trinity's domes in the trash and have someone else cut you some. CPI big bores like higher compression BTW. You could also adjust the timing till you get it where it will jet easy. There should be a motors happy spot where it runs right dont be afraid to go less or more 6 or even 12 degrees. Sometimes they are happy with more or less. Cams 485 likes timing. Hope I'm not giving any of your secrets out Cam.

On most motors with 39 pwks on gas 165-180 gets it with a cel needle and about a 48 pilot So I would start in the 190 or 200 range and go down as needed.

 

 

Ok 168 main 38 pilot cel needle middle clip,,,,,pulls hard now from off idle all the way to the top.

 

And for the record i have never blown o-rings,,they are the originals as are the trinity domes,,,,no detonation whatsoever.

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  • 3 weeks later...

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