Speed freak Posted April 25, 2007 Report Share Posted April 25, 2007 I have a 421cc cheetah running 38mm pwk's ...I live in florida low elivation and hot ..keep getting mixed stories on what jet sizes to run I am lean right now and am running 145 main and 42 pilot ..was thinking maybe 152 on the main would be better can any one help me out Quote Link to comment Share on other sites More sharing options...
MFIC Posted April 25, 2007 Report Share Posted April 25, 2007 I have a 421cc cheetah running 38mm pwk's ...I live in florida low elivation and hot ..keep getting mixed stories on what jet sizes to run I am lean right now and am running 145 main and 42 pilot ..was thinking maybe 152 on the main would be better can any one help me out Most run 155 mains with race gas. Maybe start at 165 or bigger and come down in 5s doing plug chops, jets are cheap replateing is not. Not every motor is the same. Im at 4500ft, 110 race gas, 39mm pwks, RDZ bowl extenders for long runs, 155 main and the power jets open 1 turn making 1230* on the EGTs at WOT. Quote Link to comment Share on other sites More sharing options...
Handyman Posted April 25, 2007 Report Share Posted April 25, 2007 the only really hot weather I ran my cheetah p.v. in was 70 degree weather and at 4500ft I was running a 142 main(should have been a 150) with a 45 pilot and clip in middle position. Quote Link to comment Share on other sites More sharing options...
MFIC Posted April 26, 2007 Report Share Posted April 26, 2007 the only really hot weather I ran my cheetah p.v. in was 70 degree weather and at 4500ft I was running a 142 main(should have been a 150) with a 45 pilot and clip in middle position. Is it a cheetah cub or a cheetah power valve? If it's a cheetah power valve, disregard my previous post. Quote Link to comment Share on other sites More sharing options...
Handyman Posted April 26, 2007 Report Share Posted April 26, 2007 Is it a cheetah cub or a cheetah power valve? If it's a cheetah power valve, disregard my previous post. Mine's a powervalve....Not sure about speedfreak's Quote Link to comment Share on other sites More sharing options...
Animalman294 Posted April 26, 2007 Report Share Posted April 26, 2007 Well, I don't want to add insult to injury, buuuuuutttttt. I think MFIC is right not every motor is the same and you need to get a starting point and go from there. It is time consuming and a real pain in the ass, but once you get it dialed in, your in like Flint...... I must have taken my carbs apart a dozen times in the past three days ( tryin' to get ready for sand mountain tomorrow, see ya there bansheeseat$$). But Jeff started me out at 172's, and a 55, in the middle clip, 1 1/2 turns out. Once I got the carbs synced I went to work on the mains and pilots, and my best results were with a 168 ( a tad rich so maybe a 165) and a 55 pilot with three turns out on the air screw (which would put me at a 52 pilot). By the way I am at 950' 70* in Northern Cali. I have a 421 cub (thanks Jeff), 35 PWK's, T-5's (I know, don't Start). Anyway, just get a starting point and then go from there, but you need to feel what the bike is doing and that was what I was doing wrong. Once I started doing that, I had a direction to go............ Good luck man :biggrin: Quote Link to comment Share on other sites More sharing options...
Handyman Posted April 26, 2007 Report Share Posted April 26, 2007 Well, I don't want to add insult to injury, buuuuuutttttt. I think MFIC is right not every motor is the same and you need to get a starting point and go from there. It is time consuming and a real pain in the ass, but once you get it dialed in, your in like Flint...... I must have taken my carbs apart a dozen times in the past three days ( tryin' to get ready for sand mountain tomorrow, see ya there bansheeseat$$). But Jeff started me out at 172's, and a 55, in the middle clip, 1 1/2 turns out. Once I got the carbs synced I went to work on the mains and pilots, and my best results were with a 168 ( a tad rich so maybe a 165) and a 55 pilot with three turns out on the air screw (which would put me at a 52 pilot). By the way I am at 950' 70* in Northern Cali. I have a 421 cub (thanks Jeff), 35 PWK's, T-5's (I know, don't Start). Anyway, just get a starting point and then go from there, but you need to feel what the bike is doing and that was what I was doing wrong. Once I started doing that, I had a direction to go............ Good luck man :biggrin: You're very correct. every engine is different. Just to show that here's an example....you run a 168/55 with 3 turns out on the screw and I run a 142(should be a 150) with a 45 pilot with 1.5 turns on the screw. and this is for the same mountain. Bansheeseat$$ will probably have different jetting setting if he had the same motor as you or I. I'm not going to mention the beast of a motor he has in his '06 because that's in a whole other ballpark. Quote Link to comment Share on other sites More sharing options...
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