apeik

They're actually more angle than a 573.piston, I put a piston in the dome before I put them in. I'm pretty sure theyre 11 degrees, these domes were run in another pump gas cub before mine I think.

if i cant figure it out this weekend, ill have some different domes made of course.

There's nothing plumbed wrong, all lines are clear, silencers and pipes are clear, just went back on yesterday. Im on my second set of domes, these look, by eye, about the same as any pump gas cub dome. In case anyone missed it ill post it again, they are the bottom domes, old one's that were weird were on top.

Ya, I'm going out this weekend to do more testing, hopefully I can figure something out. I'll have domes made if it could possibly be a problem. The first set of custom domes was a complete failure, I'm sure people remember that thread.

It actually has a brand new set of PWK 35mm's on it now...i just used my old post so people would see the background. ive been running it at +3 timing, but set it at +0 today. Can i use a timing light to make sure it's advancing/de-advancing correctly?

i went as far as putting rtv on the exhaust flanges to make sure there isnt any way it could scavange fresh air if it somehow leaks. Gonna try running straight distilled water instead of 50/50. The next option will be adding vp110 or whatnot, if the temp's drop dramatically it's deto. Last season the weird domes in top of pic, i had it running q16 and it still ran hot, and detonated, but it also wouldnt take more than a 165 main without bogging indefinetly.

ya. held 6 psi for 6 mins earlier today, needle never moved(yes it goes down if it leaks, took shrader out when i built it.) added pic of dome...i would think deto as well...but .051 squish, 131 kicking psi...good 91 pump gas, large jets. dunno where to go. i have a high flow impeller on the way even though the stock on that was in it was still technically in working order.

They are the dome in the bottom of the pic, top is the old one's. They are normal 24cc hemispherical cub domes. it's got 131 maybe a little more kicking compression, so it's pretty mild. and up top it run's amazing, no breaking up or anything weird now that it's got 172+ mains in it. Passed leak down again today just to be sure.

stock cdi, stock coil, racetech electric stator. timing is set at 0 now, but was set at +3 until today. Gas was brand new from costco on friday(usually fresh cause they sell 40-60k gallons a day). Ive been wondering about timing as well, i pulled stator off, made sure woodruff wasnt sheared and everything was doing it's job.

Also want to add, that it never overflowed the coolant, and never burned any up, radiator was completly full after trip, three week old orings, dont appear to be pressurizing the cooling system, or eating coolant. Doesnt smoke that much for having 60 pilots and 180 mains in it either. Again, thanks in advance. Also anyone know someone that's good with cubs in/near san diego, for dyno tuning, or problem solving?

So time to revive this thread months later, because im still having heat problems. setup as of now is: ported 421 cub, fresh nikasil and pistons. cpi sb sf inframes new 35mm pwk carbs from fast. 8" pods. oversized alum. radiator. basically new Gutted gascap, and a dual pingle 91 Pump gas, 24cc domes, .051 squish, pro design head. 131 psi kicking compression when it went together Before i left it passed leakdown, new spark plug caps just in case. Have went through 158-180 main jets, both cel and dgk needles, and 48-60 pilots. Currently sitting with the 180 mains and 60 pilots, dgk in the 4th clip. This should be basically Pouring fuel into the cylinders, but it still runs hard as shit up until the top of 5th gear(69mph, 15/41 gearing), but basically wont pull 6th and kinda lags going into the powerband a little. Anything less than a 172 main would back a plug out. The biggest problem is the temp shoot's sky high in 1-2 wot runs at the drags at gordons well. I cant even ride it because i dont wanna melt something down. It blow's past 200 degree's in one pass no matter what main's i have in it. I just got home, and checked the impeller, the flywheel key to make sure it didnt shear or anything. The impeller has about 1/8th inch play between the housing and plate that covers impeller, i havn't found much about the impeller itself getting worn and not circulating coolant. Anyways sorry for the long winded post, i just wanna get all the info in. Been battling this thing for a long long time, and im literally out of ideas, the only way i can actually test to see if it's gonna overheat is to actually get out to the desert, get in sand and get past 4th gear. I've wasted like 4 trips now with an unridable bike and any help at all or idea's, expierences would be greatly appriciated. Thanks, Aaron. And for more related to this, I had another thread, http://bansheehq.com/forums/index.php?showtopic=169536

dune port and fmf's/stock carbs works pretty well, was an awesome dune bike when mine was set up like that. Word of caution though, if you decide to get it ported, get the crank welded so it doesnt seperate and machine your cases/blow out bearing's and crank seals. i got maybe 6 trips before mine fell apart.

Hmm, was running bigger mains too I suppose

lol, on vp q16, i managed to burn 2 gallons in about 8-10 miles, 60+ mph, apparently it's thin.

I've actually been to evan's shop when i bought my stator about a year ago, he's know's his shit, and everything seemed legit. Let's hope it's still that way, because he puts out a good banshee stator.

^ lol it's not like you're life depends on them. 99 cent store FTMFW!

With that exact same setup, the pipes/carbs/hjr dune port/timing, i ran a 155-158 main, N68A needles middle clip, and it ran like a sewing machine. Now about pilots, i got handed 68's, put them in and never knew they were that big until after a whole season, so it made it a little to rich unless i was down to 155 on the main. Id say try a 48-55 pilot maybe, and go on the airscrew from there. I actually got this jetting from kevin when i got it ported and switched carbs and im guessing the pilot was an accident since the print is impossible to read. This info is all reguarding gordons well only. Your milage may vary, but hopefully this get's you sorta close.

from what ive read, id imagine to much squish band velocity could be a bad thing if you're not running high octane, but there's about a million people more qualified to answer this.

well yea, but i wanted to get it close, and im pretty limited on space. I might try a 55 pilot with this same setup and see how it acts, right now it smokes pretty heavily -- but it does run great.

small update, just ripped it around the building a few times, 60 pilots, 1.5 turns out on the airscrews, cel on 4th clip, 158 mains, absolute beast, at least upto third gear. Thanks jmadd for the pilot suggestion, and everyone for helping out. Now just to get it wide open and see what main i need.

sittin at 60 pilots 1 turn out on the airscrew, cel on the 4th clip, 158 mains, appears to run pretty good, will get to run it a little later at 5pm. It appears to have richen'd up the main quite a bit moving to such a big pilot. Im afraid to go any smaller on the main though, 158 seems small when most everyone says they run 160-162. I've read of a few people with ported cubs all the way down to a 152, but i dont wanna burn it down, i need to find somewhere close that i can do a plug chop, since im in a business park in a populated area. Anyone had a ported cub that ended up being jetted this way? I've spent probably upwards of 20 hours searching and reading.

The carbs are basically brand new from jeff at fast a few month's ago, only ran it once before i tore it down. Running a dual pingle and all that jazz, floats i checked out of the box and were perfect. Timing is set at +3 at the moment, and when i first put it together last week cold and fresh it was 130 psi in each hole, so imagine it'll be going up. I know it's not gonna have much bottom end, it just has literally a flat spot were it hangs right before powerband going from quarter throttle to wide open, then screams. Gonna mess with it more today, and move to a 52 or 55 pilot, cel middle then one clip lean, with 158 mains. If that fails im going to go richer on the main by a bunch and see what changes. With a 50 pilot, 162 main, cel middle clip if was damn close, but had that flat spot, and i know from last year it will make riding it in the dunes difficult. I could ride around perfectly fine below half throttle and it would pull me around awesome, but if i hit that dead spot you'd basically have to rap it out or clutch it past that point into the powerband. Ill also see if i have some 60 pilots and try that at some point . This is supposed to be ported by passion, i know it's not stock, the port hights werent messed with, but the port shapes are a little different, and ive heard sometimes ported cubs like leaner jetting to some extent.

it seems to be a problem when the throttle is actually pinned which makes me think main, but going down didn't help, so maybe ill go up. my ported stock cylinder motor with 28pwk's was at 155-158 mains, with 68 pilots...(builder gave them to me by mistake i think) and i just put them in, bike took like 10 mins to warm up but ran like a seweing machine for a whole season.

i have 48,50,52,55, 68... you really think i could end up with a pilot that fat? leak down test passed with flying color's, it's synced. Also should note i tried 158,160,162 mains, with the 158's in it pulls the hardest, but i dont have room at my shop to do an actual plug chop.

so, i got this thing running, it runs way better than it ever has. I have a jetting question(brand new 35mm pwks) i started with 162 mains, cel middle clip, 48 pilot, and it ran pretty decent. Two questions really, no matter what pilot i have in it, when i stab the throttle it cuts out and kinda bogs and will sometimes actually die if you keep it pinned Unless i have the the airscrews 1/2 turns out. I went up to a 50 pilot, and also tried a 55 just to run it up but it's the same no matter which pilots i use, it will rev out clean but kinda rough as long as the airscrew's are run in to 1/2 a turn, any further out and it cuts out when you stab it. I have 50's in it right now which should be damn close at 1 1/2 turns out. I have also tried CEL needles in the middle, and 4th clip(richer) and DGK needles in the middle and 4th clip. I have yet to try one clip lean on either set of needles. This pretty much ties into my second problem(this is with 160-162 mains, CEL middle or 4th clip, 50 pilots half turn out, sea level san diego, pump gas, 24cc domes), which is when you roll on the throttle right before powerband it hangs up for maybe quarter of a second or more, or maybe i should say, Delays, then smashes into the powerband and runs awesome. It doesnt seem right that i need to keep the airscrews so far in which makes it richer at idle. Also it delays before powerband even with the airscrews half a turn out. Im pretty sure the two problems are tied together somehow, only thing i havn't tried is 2nd clip on either set of needles. Going to the DGK in the 4th clip made it much worse(richer needle and clip). Sorry for the wall of text, and thanks to anyone who has any input.