shee4202 Posted June 4, 2015 Report Share Posted June 4, 2015 I've got a 485 cheetah with power valves. Trintiy state 4 exhaust. Keihin PWK 35mm carbs. 4 degree timeing advance. 93 octane pump gas @ 32:1. NGK BR8ES Spark plugs @ 0.030" gap. At WOT the top end power seems to level out pretty quick. It almost seems as if I'm draining the bowls, but could that be? Could the carbs be too small. The low and mid power are there all the way. It's just the top that's giving me trouble. For years before the 485 I was running a cheetah 421 with the same pipes and carbs. I never had this problem with the 421. Its top end seemed to never level out. The RPM's just kept climbing and climbing. The only thing that I changed was the jetting. Rite now I'm at a 160 for the main and 45 for the air. The needle clip position is in position #3. The plugs are a little darker then they should be, not too bad, but I've got a little more tuning to do. Any suggestions? Anybody out there running a cheetah 485, what is your set up like? Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted June 4, 2015 Report Share Posted June 4, 2015 Are you sure your powervalves are working? If they are, have you checked to see if they open all the way up? I had to cut my powervalves to match the exhaust port. Quote Link to comment Share on other sites More sharing options...
shee4202 Posted June 5, 2015 Author Report Share Posted June 5, 2015 Are you sure your powervalves are working? If they are, have you checked to see if they open all the way up? I had to cut my powervalves to match the exhaust port. I believe they are, but I will be checking just to make sure. Quote Link to comment Share on other sites More sharing options...
98_sheester Posted June 5, 2015 Report Share Posted June 5, 2015 Cut those threads off to see what your ghost ring looks like Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted June 6, 2015 Report Share Posted June 6, 2015 Check powervalves and domes. Also possible that those pipes are just a bit small for the near 500cc motor. Quote Link to comment Share on other sites More sharing options...
shee4202 Posted June 12, 2015 Author Report Share Posted June 12, 2015 (edited) I've got a buddy with the same engine set up except he's running Mikuni 36mm carbs and the thing runs great. I tried the carbs out on mine and hit a straight stretch of road and it seems to pull more in the top end where it wasn't before. I was thinking the pipes could have something to do with it too. I was just reading in another post that cheetah domes are trouble. Why is that Edited June 12, 2015 by shee4202 Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted June 12, 2015 Report Share Posted June 12, 2015 It's the trinity cut domes that are a problem. There seems to be a lot of their domes that are cut wrong. Instead of the squish band opening up as it comes to the middle, it gets tighter. Sent from my VS980 4G using Tapatalk Quote Link to comment Share on other sites More sharing options...
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