sick421 Posted June 4, 2014 Report Share Posted June 4, 2014 well I been debating for a wile regarding switching from 35mm pwks to 39's for my drag ported 421. I even made a few posts in the past asking if it would be worth the time and money in switching to 39's, some said yes its a night and day difference other said no stick with 35's. well I finally made the jump , I just wanted to share some differences I noticed. first of all I think the switch is based on application and riding style, I noticed the 39's keep my engine a little cooler, it screams a lot harder on top and the band last longer too. but the negatives of the 39's vs 35's is bottom end loss. my motor mods are ( cpi inframes, 10in pods, +10 timing, 1cc domes on sonoco 110, vf4) the bike feels faster shifting at WOT but the rideability given from bottom end power went down. With the 35 pwks bottom and mild range power was amazing , the bike wouldn't stay on the ground, not that it doesn't get off the ground with the 39's but the torque hit was harder . The negative with 35's is only really is the over rev power falls off a little sooner. So if you are a 50/50 rider drag/duner like me the 35 pwks are king, if you lean more towards drag racing up the hill then 39's would suite you better. JUST MY 2 CENTS Quote Link to comment Share on other sites More sharing options...
Tedder Posted June 4, 2014 Report Share Posted June 4, 2014 Nice write-up Is it drag ported stock cylinders or cubs and 21cc domes? Quote Link to comment Share on other sites More sharing options...
sick421 Posted June 4, 2014 Author Report Share Posted June 4, 2014 Thank its a drag ported cub Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
cyclewizzard Posted June 5, 2014 Report Share Posted June 5, 2014 Good review Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
hp2000 Posted June 5, 2014 Report Share Posted June 5, 2014 How was the jetting differences just by the simple carb swap ? Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
sick421 Posted June 7, 2014 Author Report Share Posted June 7, 2014 The 35s were airstrikers so 45 pilot , 150 main , 1 1/2 turns air screw , CEL in middle The 39s ended up with 55 pilot , 178 main , 1 1/2 turns air screw , DGH needle in the middle clip Fuel is 110 sonoco / klotz oil 32:1 Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
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