soccer4orlife Posted June 29, 2011 Report Share Posted June 29, 2011 hey guys im located in chicago and dont really have a place to tune around my home so if anyone can throw some jeting ideas for both my steups i would appreciate it. 421 cub 68mm bore cub cyls +7 timing cpi sb inframes 35mm pwks (keihin) cool head (17cc domes) 110 octane +6 swinger 11 paddle extreme haulers clean up port 4mil 66mm bore stock cyls +5 timing cpi small bore inframes 35mm pwks with oversized bowls stock head (shaved) 110 octane +6 swinger 10 paddle extremes drag port lock up clutch elevation where we ride is around 500 above sea level. any jetting help would be awesome. thanks in advance Quote Link to comment Share on other sites More sharing options...
okbeast Posted June 29, 2011 Report Share Posted June 29, 2011 My 4mil cub with similar mods and 35 pwks has 155 main and a 48 pilot. That's around 1300 ft. elevation and I believe it is a safe jetting. You might want to start a little higher just to be safe though. Quote Link to comment Share on other sites More sharing options...
soccer4orlife Posted June 29, 2011 Author Report Share Posted June 29, 2011 thanks man ill start at 160 and work down. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted June 30, 2011 Report Share Posted June 30, 2011 T sea level 165 mains 48-50 pilots,cel 4th clip for the cub stock cyl 4mil 170-175 main 48-50 pilot cel 4th clip Quote Link to comment Share on other sites More sharing options...
SuprSlow50 Posted July 1, 2011 Report Share Posted July 1, 2011 I'm about 40minutes outside of chicago and I have a 421 cub, mods in sig, but it's basically the same setup as you and I have 155main, 48 pilot, cel needle on the 3rd clip and the plugs look good. I just don't have the compression that you have, but I think you will have a very good starting point with all the jetting advice that was given already. Quote Link to comment Share on other sites More sharing options...
camatv Posted July 1, 2011 Report Share Posted July 1, 2011 you guys shoudl try 45 pilots. would be a lil more snappy off the bottom. i have had to go down as low as 40's on pwk's with a cub. a 400 stock stroke i did ended up with 35 slows and 168 mains.. but always jet to what the motor wants.. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted July 3, 2011 Report Share Posted July 3, 2011 Watch the compression on that 421 17cc domes are crazy IMO Quote Link to comment Share on other sites More sharing options...
Oregon dunner Posted July 6, 2011 Report Share Posted July 6, 2011 I have a 4mill 421 cub with 39 pwks and 17cc domes. I run a 45 pilot and a 155 main and it runs great on the Oregon coast. I use a 40:1 mixture with VP racing c12 fuel. Its a little rich but runs good. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted July 6, 2011 Report Share Posted July 6, 2011 I have a 4mill 421 cub with 39 pwks and 17cc domes. I run a 45 pilot and a 155 main and it runs great on the Oregon coast. I use a 40:1 mixture with VP racing c12 fuel. Its a little rich but runs good. damn same set up on a 421 by me is 178-185 mains 52-55 pilot,what a diffrence Quote Link to comment Share on other sites More sharing options...
Oregon dunner Posted September 7, 2011 Report Share Posted September 7, 2011 Must be the air over there. Quote Link to comment Share on other sites More sharing options...
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