possum Posted April 1, 2013 Report Share Posted April 1, 2013 ok gotchya. yea man somethin aint right. cooling system or dome specs and carbs or an accumulation of all. I dont think i seen what domes you have in there or what compression, squish, cc etc... Quote Link to comment Share on other sites More sharing options...
apeik Posted April 1, 2013 Author Report Share Posted April 1, 2013 Ya, ill pull the head and snap pics of the domes, never seen any like them Quote Link to comment Share on other sites More sharing options...
apeik Posted November 5, 2013 Author Report Share Posted November 5, 2013 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 Quote Link to comment Share on other sites More sharing options...
apeik Posted November 5, 2013 Author Report Share Posted November 5, 2013 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? Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 7, 2013 Report Share Posted November 7, 2013 What CDI do you have? And what is your timing set at? Quote Link to comment Share on other sites More sharing options...
apeik Posted November 7, 2013 Author Report Share Posted November 7, 2013 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. Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted November 7, 2013 Report Share Posted November 7, 2013 Could the domes be to agressive for the pump gas? Quote Link to comment Share on other sites More sharing options...
apeik Posted November 7, 2013 Author Report Share Posted November 7, 2013 (edited) 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. Edited November 7, 2013 by apeik Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 7, 2013 Report Share Posted November 7, 2013 ^^^ Was going to be my next question..... It sounds like it's lean to me-but if richer isn't helping make me wonder if it is running under a slight DET condition, driving piston crown heat up... I read earlier it passes leakdown, right? -so no air leaks? Quote Link to comment Share on other sites More sharing options...
apeik Posted November 7, 2013 Author Report Share Posted November 7, 2013 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. Quote Link to comment Share on other sites More sharing options...
apeik Posted November 7, 2013 Author Report Share Posted November 7, 2013 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. Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 7, 2013 Report Share Posted November 7, 2013 I highly doubt it's the cooling system's fault, based on everything else you have said. Bigger carb would help-but you should still be able to get the 28's to run. I've seen these domes cause problems with the squish band being too wide, but that would be odd with your 24cc and .050 squish... Have you tried it with the timing at 0 yet? Quote Link to comment Share on other sites More sharing options...
apeik Posted November 7, 2013 Author Report Share Posted November 7, 2013 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? Quote Link to comment Share on other sites More sharing options...
KaN Powersports Posted November 7, 2013 Report Share Posted November 7, 2013 Yes, use a spare battery to power the light, and hook it to either plug wire. Set your cylinder to TDC (A homemade piston stop can easily be fabricated out of an old plug-break all of the center out, and fit a bolt/nut through the center {I grind the head into a smooth button}-handy cheap item to have in your tool box) . Make a reference mark, or pointer, and go from there.... You can use this to check the phasing of the crank accurately/quickly too, as well as many other often overlooked things-a degree wheel and piston stop should be sitting right next to your leak down kit in you toolbox-haha Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted November 7, 2013 Report Share Posted November 7, 2013 Maybe others can give some feedback on this one, but could the pipes be an issue? I was thinking the SB CPI's might be too small for a 421 in the dunes. If so the pipes could be backing heat into the motor on the WOT runs. Sorry I just can't remember the design cc's of the SB CPI's. But I thought the BB pipes were for 420+ 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.