apeik Posted March 3, 2013 Author Report Share Posted March 3, 2013 At 155 mains, 48 pilots, n68a needle middle clip, still has a slight stumble going into power band, cold weather helped some, and going down on the mains is the only thing that's made it better. I've tried everything from leaning out Tue pilot, needle, going richer on all three at seperate times. I spent like 5 hours today trying to get it dialed. Slightly scared to go to 152 mains. I'll post plug chop pics tomorrow when I'm not on my phone. Any tips would be appreciated Quote Link to comment Share on other sites More sharing options...
JKJK Posted March 3, 2013 Report Share Posted March 3, 2013 A set of JJH needles should give you the results your looking for.Depending on how temperary they will be,you'll have to decide if it;s worth the cash output. Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted March 3, 2013 Report Share Posted March 3, 2013 A jjh has the taper you might need,now food for thought.i built a an aggressive ported 4 mil for Nasty racing that came in at 168 main,50 pilot ,Jjh needle 4th clip,a rail ported 350 I'm working on rite now came in at 155 main 52 pilot n68a needle in the middle.you might be experiencing to much pull across the emulsification tube making jetting a lil more difficult Quote Link to comment Share on other sites More sharing options...
apeik Posted March 3, 2013 Author Report Share Posted March 3, 2013 Thanks guys, ya just trying to finish put the desert season, 2 trips or so. I tried lgn needles, and it wouldn't even rev out, ill have to pick some jjh needles up and try it out. It's crazy fast, just hard to dune when it stumbles right before the powerband. When I get diff needles, ill bump the main jet back up and lean out the needle. It's what it feels like it needs. Quote Link to comment Share on other sites More sharing options...
apeik Posted March 4, 2013 Author Report Share Posted March 4, 2013 So I got a set of jjh needles on the way. Another question, I'm guessing its because its a drag port and my pipes are stuffing it up a lot, bit I was running way hot this weekend, average 200 degrees running 30-50 miles an hour, with spikes upto 218. Anyone have any luck with aluminum radiators? I need to drop 10 to 20 degrees to be comfortable. That and do the billet hi flow impellers work too? It was warm out at almost 80 degrees, but it used to run quite a bit cooler with stock ported jugs. Thanks guys. Quote Link to comment Share on other sites More sharing options...
JKJK Posted March 4, 2013 Report Share Posted March 4, 2013 I would guess you will find some sort of issues with your cooling system components,worn impeller,clogged radiator,ext.The Cub cylinders should run cooler than the stockers. Quote Link to comment Share on other sites More sharing options...
apeik Posted March 5, 2013 Author Report Share Posted March 5, 2013 Ya, I'm gonna check the impeller and gear, ordered an oversized radiator and gonna run it without a grill in the front shroud. It never used to run this hot, maybe once or twice when I was riding with The wind in 100+ weather Quote Link to comment Share on other sites More sharing options...
apeik Posted March 5, 2013 Author Report Share Posted March 5, 2013 left is 160 mains, right is 155's they look pretty much the same to me. Quote Link to comment Share on other sites More sharing options...
apeik Posted March 27, 2013 Author Report Share Posted March 27, 2013 Just put CPI inframes on today, got jjh needles in it, hopefully it helps with the stumble before powerband. I'll find out thurs hopefully, got a desert trip Friday, don't wanna spend all weekend messing with it. Quote Link to comment Share on other sites More sharing options...
apeik Posted March 28, 2013 Author Report Share Posted March 28, 2013 guess it wanted 152 mains, seems lean on a drag ported cub but it's the only thing that's cleaned up the stumble, tried 45 pilots, the 48's were spot on. Tried every needle position on both n68a and the new jjh needles. So i guess this is just the motor telling me what it wants? tiny carbs apparently suck alot of fuel through the jets. well see how it goes this weekend, just dont wanna melt a motor down. Quote Link to comment Share on other sites More sharing options...
apeik Posted April 1, 2013 Author Report Share Posted April 1, 2013 so went out and wasted another weekend not being able to get the bog out of this motor right before powerband unless i leaned the main way out(152's) and it was pretty much gone, but you could tell the topend was to lean, and backed a plug out. So on to the problem, this thing runs hot, it's got a new 40mm aluminum radiator, good impeller, engine ice, cpi pipes now and still stuck with the small 28 pwk's. 10 minutes of riding im pushing 200-218 degrees. This is moving quite a bit of air across the radiator 35+ miles an hour average, the grill is almost non-existant since i trimmed it out. Do drag ports just run hot? cubs are supposed to run cooler than stockers, and it's running quite a bit hotter then it used to with just a ported motor. This is with custom cut domes made for this motor, loose squish(.056) and running on a 50/50 mix of pump/vp110. It was hot out, at 90 degrees, but it got hot at night even in 60 degree weather. Just kinda at the end of my rope, obviously carbs are next(not going to bother buying more needles with a leaner taper for these tiny carbs), but i cant imagine it's going to help with the heat issue whatsoever. Any input on drag ported cubs is welcome. The domes have 4 angles in them, and were supposed to help push the heat out of the motor. Quote Link to comment Share on other sites More sharing options...
WINDYCITYJOHN400 Posted April 1, 2013 Report Share Posted April 1, 2013 A- Running carbs that small on that motor is just not a good combo. B- What pipes are you running. Maybe they are backing heat into the motor. C- Your cooling system is fine....your jetting is more than likely the issue. Quit wasting money on weekends and trips and spending all your time trying to jet something that is just begging to be re-done once you get new carbs. Just get the right carbs, THEN go tune and play. Quote Link to comment Share on other sites More sharing options...
possum Posted April 1, 2013 Report Share Posted April 1, 2013 small carbs like he^^^said. And I think your lean on the mains. Dont even waste your time doing plug chops. just jet it up to see how it responds. My cub runs at 150-160 degrees all day dunning and 175 when dragging. Quote Link to comment Share on other sites More sharing options...
apeik Posted April 1, 2013 Author Report Share Posted April 1, 2013 I had 2 more trips to finish the season so I was trying to make it work. I'm running a mint set of sb/sf CPI's now, I got them first cause that's what the sponsor told me would compliment the porting. I started at 170 mains last trip and worked my way down to 155's. With 170's it wouldn't even rev out..just run almost up to powerband and bog indefinitely. I'll be getting carbs when I get more money, guess ill just wait, maybe ask Jim his opinion on the heat. Quote Link to comment Share on other sites More sharing options...
apeik Posted April 1, 2013 Author Report Share Posted April 1, 2013 Forgot to add 2 runs down the drags would put me over 200 degrees, even jetted rich, it just isn't normal, used to hotlap my hjr dune port stock cyl and never even see 190. Quote Link to comment Share on other sites More sharing options...
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