Power_Man Posted October 22, 2015 Report Share Posted October 22, 2015 Picked up a new banshee and trying to get it going. 2001 421 CUB 39PWK 8" pod filter with outerwear 185 mains 55 pilot DGH Top clip Shearer in frames Cool head with 24cc domes .047 squish Now the problem is, starts and idles okay. Not much low end, and mid end is sputtering. If I can get past the sputter I can get into power band. Also I can feel engine vibration in the mid/low range when sputtering. Vibration goes away up top if I can get it there. Quote Link to comment Share on other sites More sharing options...
Power_Man Posted October 22, 2015 Author Report Share Posted October 22, 2015 Elevation is sea-level. The bike had never been fired after rebuild. I gave it leakdown test and no loss after 15 min. Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted October 22, 2015 Report Share Posted October 22, 2015 probably just really rich. Crank could also be out of true Quote Link to comment Share on other sites More sharing options...
FullThrottle_06' Posted October 23, 2015 Report Share Posted October 23, 2015 At sea level, 185 main sounds waay rich. With 24cc domes I would assume your running pump gas? I don't know what your ambient temps are this time of year where you live but you gotta keep that in mind as well. I would recommend coming down on both your main and pilot. Maybe 170 & 50, 1.5 turn out on air screw, needle middle clip. Even at that I still think you would be rich. You could also change needles and go to a CEL instead of the DGH? I wouldn't go make a bunch of changes all at once. Just do one thing at a time and see what happens. Also, I've seen dirty outerwears mess with jetting. Quote Link to comment Share on other sites More sharing options...
Power_Man Posted October 23, 2015 Author Report Share Posted October 23, 2015 At sea level, 185 main sounds waay rich. With 24cc domes I would assume your running pump gas? I don't know what your ambient temps are this time of year where you live but you gotta keep that in mind as well. I would recommend coming down on both your main and pilot. Maybe 170 & 50, 1.5 turn out on air screw, needle middle clip. Even at that I still think you would be rich. You could also change needles and go to a CEL instead of the DGH? I wouldn't go make a bunch of changes all at once. Just do one thing at a time and see what happens. Also, I've seen dirty outerwears mess with jetting. yes sir, running 94 pump gas at 32:1 amsoil ambient temp is 55-60*F right now. ill try changing out the jets and putting needle back to center clip. Jeff at FAST says the cubs like to run the DGH? Thanks for the help guys. i hope the vibration is from it just being to rich and not running right. i forgot to check all my engine mounts, will check them out as well. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted October 23, 2015 Report Share Posted October 23, 2015 Cubs like the dgh needle usually fourth clip , 55 pilot is normal, your main is at the top end of spectrum that I usua see at sea level .i would swap the stator with a known good one Quote Link to comment Share on other sites More sharing options...
FullThrottle_06' Posted October 23, 2015 Report Share Posted October 23, 2015 yes sir, running 94 pump gas at 32:1 amsoil ambient temp is 55-60*F right now. ill try changing out the jets and putting needle back to center clip. Jeff at FAST says the cubs like to run the DGH? Thanks for the help guys. i hope the vibration is from it just being to rich and not running right. i forgot to check all my engine mounts, will check them out as well. Cubs like the dgh needle usually fourth clip , 55 pilot is normal, your main is at the top end of spectrum that I usua see at sea level .i would swap the stator with a known good one I'm not afraid to admit that Jeff and Sleeper06 have a lot better advice than myself. However, I do know what it feels like to have problems and no sense of direction to try and correct them. Just tackle the issue one move at a time, if it helps grab a pen and paper and document what you changed and what the outcome was. There are a quite a few knowledgeable people on this site so take the advice given and you'll be fine. 1 Quote Link to comment Share on other sites More sharing options...
Power_Man Posted October 23, 2015 Author Report Share Posted October 23, 2015 Cubs like the dgh needle usually fourth clip , 55 pilot is normal, your main is at the top end of spectrum that I usua see at sea level .i would swap the stator with a known good one When i pulled the flywheel off it looks like the stator is brand new, Not saying its not the problem as i was thinking it could be "electrical" and that's why i swapped flywheels thinking a little rust or rattle was the issue. However a good flywheel made no change. I will defiantly drop main jet a few sizes and see if it makes a difference. THANKS! I'm not afraid to admit that Jeff and Sleeper06 have a lot better advice than myself. However, I do know what it feels like to have problems and no sense of direction to try and correct them. Just tackle the issue one move at a time, if it helps grab a pen and paper and document what you changed and what the outcome was. There are a quite a few knowledgeable people on this site so take the advice given and you'll be fine. I appreciate all help, little or big. Thank you. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted October 23, 2015 Report Share Posted October 23, 2015 yes sir, running 94 pump gas at 32:1 amsoil ambient temp is 55-60*F right now. ill try changing out the jets and putting needle back to center clip. Jeff at FAST says the cubs like to run the DGH? Thanks for the help guys. i hope the vibration is from it just being to rich and not running right. i forgot to check all my engine mounts, will check them out as well. Which Amsoil? Their synthetics mixed over 40:1 seem to really hurt the combustion. It'll foul plugs at 32:1 Quote Link to comment Share on other sites More sharing options...
Strm Trpr Posted October 23, 2015 Report Share Posted October 23, 2015 Which Amsoil? Their synthetics mixed over 40:1 seem to really hurt the combustion. It'll foul plugs at 32:1 For instance, Amsoil Dominator is formulated and safe to run in oil injection and pre-mix at 50:1. What's your plan of attack? If it were me and I was using Dominator, I'd mix a fresh batch of fuel at 50:1, or at the very least 40:1 which is exactly 1pt to 5 gallons of fuel. 94 octane, where do you even get that? What is requiring you to run 94 octane? Is your Cub Ported? I don't think 24cc domes require anything more than 91 octane, but I may be mistaken. If higher octane is not required, ie., due to high compression or high timing advance, it can hurt combustion. Granted you're only using 94, so that shouldn't be the problem. First things first. Are you properly sync'd with a FAST Sync tool at an idle of 1500 rpms minimum? You want the airscrews about 1.5 turns out and the throttle snappy as fuck off idle. You will achieve this by dialing in the pilots. If the airscrews are between the the filter and the carb slide, then turning the airscrews in will richen the mixture, just like stock carbs. Are you sync'd at part throttle, say 5000 rpms? I use a simple eBay digital 2 stroke tach. Passed leakdown, so that's good. I know it's a new build, but what's the kicking compression with the throttle WFO? And like mentioned above, write everything down. If the needle clips are in groove 1, at the top, blunt end of needle, then you have the needles fully lowered into the needle jet making the mid-range mixture full lean, does that even make sense? What jetting have you tried? Quote Link to comment Share on other sites More sharing options...
Power_Man Posted October 25, 2015 Author Report Share Posted October 25, 2015 Okay, good news. My plan of attack: I dropped jets to 175 and needle to middle clip. I then resync'd carbs and went for a quick (1.5 min) rip. 75% of the vibration is gone. 95% of the bog/mis is gone. So thanks to you all I'm headed right way. Temps are dropping every day up in Ontario Canada, so now that I know I don't need to buy electrical parts I'm going to fog it and start fresh next year. I'm going to drain all the fuel and start fresh next year at either 40:1 or 50:1. To answer some of your questions, I don't think the jugs are ported other than a clean up port, but I see FAST did a case port. Up here in Canada we can get 94 fuel from PETRO CANADA. Who bought out Sunoco who carried it exclusively before. Compression was around 135 but might change domes in spring to get 150+ Air screw were 1.5 out. Thanks again all! Quote Link to comment Share on other sites More sharing options...
Darkblade Posted November 4, 2015 Report Share Posted November 4, 2015 i had a similar problem and i had about 130 pis comp and was running 93 octane and it ended up being too high of fuel causing it to bog at low end , mid range and a weaker pwr band so i just got some 89 and it helped a lot that might be ur problem try 91 Quote Link to comment Share on other sites More sharing options...
Deadbeat Posted November 5, 2015 Report Share Posted November 5, 2015 no thats retarded Quote Link to comment Share on other sites More sharing options...
lil Doobie420 Posted November 5, 2015 Report Share Posted November 5, 2015 haha Quote Link to comment Share on other sites More sharing options...
Deadbeat Posted November 5, 2015 Report Share Posted November 5, 2015 if you`d have said "my 130 comp motor ran better on a lesser octane fuel than 100+" there would be some merit to that. using a too high of an octane fuel in a low comp motor it will struggle to burn it efficiently , but dropping from 94 octane to 89 fixed the low end bog...no 2 Quote Link to comment Share on other sites More sharing options...
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