jst854 Posted June 21, 2010 Report Share Posted June 21, 2010 Here is what I have, a 4 mill long rod stroker, aggressive port, not quite a full out drag port though, 34mm carbs, and cpi inframes. Where should I start for jetting, I have a 410 in there now and I cant get any top end, the same happened with 310. any suggestions Quote Link to comment Share on other sites More sharing options...
fastbanshee8 Posted June 21, 2010 Report Share Posted June 21, 2010 Fire it up, take it for a spin, and pull the chokes out, to see if it gets better, or worse. If' it's worse, then you're rich, and if it's better, you're lean. Quote Link to comment Share on other sites More sharing options...
pr0blumz Posted June 21, 2010 Report Share Posted June 21, 2010 (edited) What brand of 34mm carbs? If they are PJs, you are way fat on the mains. Edited June 21, 2010 by pr0blumz Quote Link to comment Share on other sites More sharing options...
fastbanshee8 Posted June 21, 2010 Report Share Posted June 21, 2010 They sound like Mikuni's, with the sizes of the mains he has tried. Quote Link to comment Share on other sites More sharing options...
jst854 Posted June 21, 2010 Author Report Share Posted June 21, 2010 They sound like Mikuni's, with the sizes of the mains he has tried. They are mikuni and with the 300 it seemed to rev out a little better with there choke on but would not idle under half throttle. I did not try the choke with the 400s in there.i am thinking I might try some 360 and see how that works but that seems kind of lean yup me. What do you guys think? Quote Link to comment Share on other sites More sharing options...
jst854 Posted June 22, 2010 Author Report Share Posted June 22, 2010 They are mikuni and with the 300 it seemed to rev out a little better with there choke on but would not idle under half throttle. I did not try the choke with the 400s in there.i am thinking I might try some 360 and see how that works but that seems kind of lean yup me. What do you guys think? Sorry for the spelling and grammar mistakes, i typed that from my phone. But the Carbs are Mikuni's. When I had the 310's in the bike ran a little bit better on the top but no where near perfect when I had the choke on. When I switched to the 410's it seemed to run the same as with the 310's in it. It could get into the powerband range but did not have any pull at all like it should. So I am thinking that the 310's where too lean and that the 410's where too rich. What do you guys think of that? Quote Link to comment Share on other sites More sharing options...
jst854 Posted June 22, 2010 Author Report Share Posted June 22, 2010 I am also running 2 clamp on filters with prefilters, so no airbox at all. Quote Link to comment Share on other sites More sharing options...
pr0blumz Posted June 22, 2010 Report Share Posted June 22, 2010 Try 330 mains and go from there. Quote Link to comment Share on other sites More sharing options...
jst854 Posted June 24, 2010 Author Report Share Posted June 24, 2010 I started making my way back down and I am at 270's now and it is starting to run a little better. It just seems weird that this set up would take such small jets. Is there something different about bigger carbs that make up for smaller jets? Quote Link to comment Share on other sites More sharing options...
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