Joejr915 Posted May 3, 2010 Report Share Posted May 3, 2010 i have a 421 with 39pwks. what size filters should i use and what jetting also. im about 1000-1500 in elevation with shearer drag pipes. Quote Link to comment Share on other sites More sharing options...
banshee332 Posted May 3, 2010 Report Share Posted May 3, 2010 i have a 421 with 39pwks. what size filters should i use and what jetting also. im about 1000-1500 in elevation with shearer drag pipes. get yourself some 14 inch filters. del needle middle clip 55-58 pilots 165-168 mains to start air screw about 1 turn out Quote Link to comment Share on other sites More sharing options...
dajogejr Posted May 6, 2010 Report Share Posted May 6, 2010 get yourself some 14 inch filters. del needle middle clip 55-58 pilots 165-168 mains to start air screw about 1 turn out That will be MORE than safely rich. On my 421 cub motor with 35PWKs I ran CEL needle, 48 pilots and 150 to 155 mains. I would grab every other size main, like a 150, 155, 160, etc. When you get just about right, then buy one of the "inbetween sizes" like a 152 or 158 if needed. Cubs love fuel, if you left it a hair rich, it'll last you a while and won't hurt a thing. Quote Link to comment Share on other sites More sharing options...
Sweet1 Posted July 20, 2011 Report Share Posted July 20, 2011 That will be MORE than safely rich. On my 421 cub motor with 35PWKs I ran CEL needle, 48 pilots and 150 to 155 mains. I would grab every other size main, like a 150, 155, 160, etc. When you get just about right, then buy one of the "inbetween sizes" like a 152 or 158 if needed. Cubs love fuel, if you left it a hair rich, it'll last you a while and won't hurt a thing. what elevation and temp were you at with the 48 pilot and 155 main? just curious, im at sea level about 50-65 deg. im running 160 main 52 pilot, both may be a tad fat. stock 421 cub no porting what so ever, and yea they rip like that Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted July 20, 2011 Report Share Posted July 20, 2011 39pwks,178 main 52-55 pilot,dgh 4th clip at sea level ,chopped perfect on 4 diffrent machines,if its ported 185 mains,unported i would go with the 178 s and try it Quote Link to comment Share on other sites More sharing options...
beebs Posted July 20, 2011 Report Share Posted July 20, 2011 39pwks,178 main 52-55 pilot,dgh 4th clip at sea level ,chopped perfect on 4 diffrent machines,if its ported 185 mains,unported i would go with the 178 s and try it Sleeper, how close does the 35mm pwk jetting compair to the 39mm on the same engine? I have a ported 421 cub that i'm gonna breakin soon also. Thinking of starting with 165/55/DGK on 4th clip. I'm at 1800ft and around 77f. Quote Link to comment Share on other sites More sharing options...
SuprSlow50 Posted July 20, 2011 Report Share Posted July 20, 2011 Sleeper, how close does the 35mm pwk jetting compair to the 39mm on the same engine? I have a ported 421 cub that i'm gonna breakin soon also. Thinking of starting with 165/55/DGK on 4th clip. I'm at 1800ft and around 77f. I have a 421 cub with 35mm PWK and have found the following setup to be good.. 160 main, cel needle in 3rd clip, 48 pilot, air screw 1.75-2 turns out. (660ft elevation) and with this weather I bumped up the clip one notch and put it at 2.5 turns out and felt great, but it didn't like it when it was 70 and ALOT less humidity,but it was about 115 with heat index. I probably could have leaned out the main to a 155 and 45 pilot, but it was just too damn hot for me. Sleeper, I too am curious as to how the jetting on a 39mm compares to a 35mm PWK. Quote Link to comment Share on other sites More sharing options...
Sweet1 Posted July 21, 2011 Report Share Posted July 21, 2011 I have a 421 cub with 35mm PWK and have found the following setup to be good.. 160 main, cel needle in 3rd clip, 48 pilot, air screw 1.75-2 turns out. (660ft elevation) and with this weather I bumped up the clip one notch and put it at 2.5 turns out and felt great, but it didn't like it when it was 70 and ALOT less humidity,but it was about 115 with heat index. I probably could have leaned out the main to a 155 and 45 pilot, but it was just too damn hot for me. Sleeper, I too am curious as to how the jetting on a 39mm compares to a 35mm PWK. When i went to 39s it was the exact same jetting as my 35s, 160 main 52 pilot, plugs look perfect. im on the oregon coast. Im going to try a 158 and 50 pilot this weekend if its 65 deg or above, was alittle fat during the day and sandfest, but boy did she run up the hill at night Quote Link to comment Share on other sites More sharing options...
beebs Posted July 21, 2011 Report Share Posted July 21, 2011 Sweet, what was the altitude there and is your cub ported? Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted July 21, 2011 Report Share Posted July 21, 2011 unported cub at sea level 162-165 depending on wheather,48 pilot for people who are duning for snappiness,cel 4th clip,i have gotton the dgk to work also you might wanna try it and i have found they do not jet the same at all,same bike went from a 162 main to a 178 in a full 1/4 pass when i switched his bike to 39s Quote Link to comment Share on other sites More sharing options...
Sweet1 Posted July 21, 2011 Report Share Posted July 21, 2011 Sweet, what was the altitude there and is your cub ported? sea level to 400-500 feet, no there is no porting at all on my bike. Quote Link to comment Share on other sites More sharing options...
Sweet1 Posted July 21, 2011 Report Share Posted July 21, 2011 unported cub at sea level 162-165 depending on wheather,48 pilot for people who are duning for snappiness,cel 4th clip,i have gotton the dgk to work also you might wanna try it and i have found they do not jet the same at all,same bike went from a 162 main to a 178 in a full 1/4 pass when i switched his bike to 39s Well every bike in our group, about 8 cub bikes are 160-162 mains, 35pwks and 39 pwks, and they are jetted for 55-65 degree weather, maybe your air is different over there?, like i said we are all alittle fat as well, all these bike vary from unported to full ported. the one that is tuned on the dyno is at 162 main 55 pilot. weather, humidity, corrected altitude all effect jetting. if i ran a 178 main in my bike it would never clear out. thats not to say thats not what works best in the big apple, thats just what works on the coast in oregon. Quote Link to comment Share on other sites More sharing options...
Sweet1 Posted July 22, 2011 Report Share Posted July 22, 2011 Im also running a cel needle, the needle you use will affect your jetting as well Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted July 23, 2011 Report Share Posted July 23, 2011 i run a dgh in 39s an cel in 35s,the air is def diffrent i have had similar discrepencies with motors on diffrent coasts even though there both sea level Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted April 19, 2012 Report Share Posted April 19, 2012 (edited) the air is def diffrent i have had similar discrepencies with motors on diffrent coasts even though there both sea level I also found this to be true. I have 34PJ's & CEG needles mid clip....here in NC at sea level, CEG needles do not like pilots smaller than a 52 pilots using the 34 PJ's. Im about to jet my un ported 421 cub also & was wondering whats a safe main to start with using this CEG needle? temp is ranging from 60*-80* , SB IF Shearers, K&N pods, VF2's, 22cc domes & 100LL ( av gas ). Edited April 19, 2012 by 252wheelieking Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.