racerdonnie13 Posted June 6, 2013 Report Share Posted June 6, 2013 I have ran my drag bike at 2 different drag events, and i was having a problem bogging off the line. Bike is a 358 cub, drag ported, vf3's, lightened flywheel, cpi oof drag pipes, override, lock up...yadda yadda. It has a set of 35 PWK carbs on it (bored to 36 on alky with power jets), and i noticed when i start the bike it sounded like only one cylinder was firing, but when i rev it a few times it revs out fine. I swapped the carbs and the problem switched sides. So i pulled that carb and cleaned it real good. Found clogged pilot. Put back together and still same problem. Pulled it off again and i noticed the "idle" screw was way out on that carb and way in on the other. So i set them the same and when i start it. it idles high, but revs clean. When i come out with the idle screws it still idles high, but it causes a hesitation when i rev. It kinda chokes then picks up and revs. This is with the slides bottomed out. I moved the needle clips from the very top clip (where they were) down to the middle clip, with little to no difference. Anysuggestions where to go from here? Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted June 6, 2013 Report Share Posted June 6, 2013 Any alky on your hand when you have it warmed up and revved to clean it out? Much alky at all and its rich on the needle. Sounds to me like yours are lean on the needle. If it idles high and or takes a few seconds to idle down thats lean on the needle. If you richen the needle clip position to the richest setting (clip all the way down , needle raised) you may need richer needles or need the dump tube drilled bigger. EGL and EGN needles are common alky needles in pwks. If its got CGL, CEL needles those are usually gas needles. I have seen CGL needles work fine on 350s with the dumps drilled but be very lean on a 4 mil, cub , or a motor with quite more timin than say 4 or 5 degrees. Since your carbs are bored can you tell me if there is any air or light showing thru next to the slide. There shouldnt be but I have seen carbs for sale recently like that and they are basically junk if bored too big. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted June 6, 2013 Report Share Posted June 6, 2013 Are you running a pump. (I hope not). You've ruled out the problem to the carbs. Float height too high in one of the carbs? Did you switch carb tops when you swapped carbs? Could just be out of sync. Doesn't take much at all for them to load up on bottom. I'm guessing that's the problem. Air screws the same? You never said what your pilots or mains are, but that isn't really your issue yet. Quote Link to comment Share on other sites More sharing options...
racerdonnie13 Posted June 7, 2013 Author Report Share Posted June 7, 2013 (edited) Any alky on your hand when you have it warmed up and revved to clean it out? Much alky at all and its rich on the needle. Sounds to me like yours are lean on the needle. If it idles high and or takes a few seconds to idle down thats lean on the needle. If you richen the needle clip position to the richest setting (clip all the way down , needle raised) you may need richer needles or need the dump tube drilled bigger. EGL and EGN needles are common alky needles in pwks. If its got CGL, CEL needles those are usually gas needles. I have seen CGL needles work fine on 350s with the dumps drilled but be very lean on a 4 mil, cub , or a motor with quite more timin than say 4 or 5 degrees. Since your carbs are bored can you tell me if there is any air or light showing thru next to the slide. There shouldnt be but I have seen carbs for sale recently like that and they are basically junk if bored too big. At idle it has a small bit of alky coming out if i put my hand by the pipes. It has EGN needles. There is no light showing on the sides of the slides. Are you running a pump. (I hope not). You've ruled out the problem to the carbs. Float height too high in one of the carbs? Did you switch carb tops when you swapped carbs? Could just be out of sync. Doesn't take much at all for them to load up on bottom. I'm guessing that's the problem. Air screws the same? You never said what your pilots or mains are, but that isn't really your issue yet. No pump, just gravity fed. Float height is good. ( same in both carbs ). I tried swapping slides also with no noticeable difference. Air screws are 1 & 1/2 turns out. pilots = 50. mains are drilled with a 1/8" bit. #6 slides. EGN needles. Slides are bottomed out then i screwed the idle screws in untill they just started to move up. Today i lowered the clip to the lowest setting. it idles a little lower (but still too high), and it smokes like a freight train from off idle to mid-top. After a few revs it cleans out up top some, but seems rich and boggy down low. Edited June 7, 2013 by racerdonnie13 Quote Link to comment Share on other sites More sharing options...
J-Madd Posted June 7, 2013 Report Share Posted June 7, 2013 Air leak or sucking water. And 50 pilots sound too small. Mains are huge though, but some times you need that on a short stroke motor. Quote Link to comment Share on other sites More sharing options...
racerdonnie13 Posted June 7, 2013 Author Report Share Posted June 7, 2013 Yea i am beginning to think i have an air leak also. Any good links on how to build a leak tester for a shee? I have one i made for a zilla that i used to have so i already have the guage and stuff. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted June 7, 2013 Report Share Posted June 7, 2013 I bought mine. Check the reeds too. Though they don't go bad often in small motors. Quote Link to comment Share on other sites More sharing options...
racerdonnie13 Posted June 14, 2013 Author Report Share Posted June 14, 2013 Well it was definately an air leak. I have those Boss racing 2 piece intakes, and it was leaking air out as fast as i pumped it in. It was leaking where the carb boot meets the billet piece. Did away with them in favor of some 1 piece intakes. Problem solved. Seems to run pretty good now, but still needs some tuning. I have 2 races this weekend so i should have plenty of time to get her dialed in. I bumped the pilots up to 55 and i set the needles on the middle clip. It wants to barely idle even with the idle screws all the way in, so i think i need to go a little smaller on the pilots and raise my needle clip a notch or 2. Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted June 14, 2013 Report Share Posted June 14, 2013 125 mains are big, but depending on a few other things you might be ok but just take some PJ out of it. What are the dumps drilled to? Quote Link to comment Share on other sites More sharing options...
racerdonnie13 Posted June 15, 2013 Author Report Share Posted June 15, 2013 Im not sure what the dumps are drilled to. ill have to measure them. I have some 113's and 108 mains i could try also. right now ive got the PJ only turned in 1/2 turn from wide open. prolly go in a little more after i make a pass and see what its doing. ill post some pics and vids after the weekend. Quote Link to comment Share on other sites More sharing options...
racerdonnie13 Posted June 18, 2013 Author Report Share Posted June 18, 2013 So i started out saturday with 55 pilots, air screw 1&1/2 turns out, needle clip in the middle, 1/8 drilled mains, power jets turned in 1/2 turn from wide open. First pass i couldnt even get it to clean out, so i changed the needle clip to the top notch. ran better but still hard to clean it out. Dropped back to the 50 pilots. Ran alot better after that, but still rich. I turned the power jets in 1&1/2 more turns (making it 2 turns closed from wide open). I was able to take off in second gear with this setting but i had to rev the piss out of it and clean it out really good. I tried to take off in second on the next pass and it bogged off the line. Should i drop my main size? i have 2 more sets of drilled jets, one set is drilled to 7/64 and has 113 stamped into them. The other set is drilled to 3/32 and has nothing stamped on the side. I wanted to get some videos so you guys could see what its doing. if i find some ill post them. I do have a couple pics though. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted June 18, 2013 Report Share Posted June 18, 2013 Keep leaning out the power jet. It's actually better to close them then count the number of turns out. If they are all the way out, sometimes a whole turn in isn't any change. It's also more precise that way to keep the carbs the same. Quote Link to comment Share on other sites More sharing options...
racerdonnie13 Posted June 19, 2013 Author Report Share Posted June 19, 2013 Ok ill try that. How will i know if in getting too lean? Quote Link to comment Share on other sites More sharing options...
J-Madd Posted June 20, 2013 Report Share Posted June 20, 2013 Go a little at a time and check the plugs after every pass. If the plug strap is gone you went too far, lol. Look up how to read alky plugs, if you haven't already. Quote Link to comment Share on other sites More sharing options...
n2otoofast4u Posted June 20, 2013 Report Share Posted June 20, 2013 main is a PIG. Like Jmadd said, start from closed to open on the PJ. REMEMBER, when the PJ is wide open more than likely its going to draw fuel on the clean out. Get off the bike and whack the throttle, watch how fast it draws the fuel up the line.What are the PJs drilled to? What ID fuel lines are on the PJs? Are they some high flow shit like a DMR? There are lots of things that could affect this! If it was mine, Id cut both the main and PJ back but thats just me. Post some more details, or a couple pictures if you dont know your setups! Quote Link to comment Share on other sites More sharing options...
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