421alkybanshee Posted July 10, 2011 Report Share Posted July 10, 2011 Ok heres what ive got: stock crank +4 timing advance coolhead with 22 domes v force 3 reeds 28 pwk carbs with LGN needles in center clip, 140 main jet, 42 pilots im at 800 above sealevel bored 60 over stock cylinders,no port job 155 lbs compression-brand new engine I know I probably need to bump up my jets to 155 or 160, with 42 pilots but i havnt made it that far yet. My problem now is I fired it up for about 5 minutes today and it seems good but the idle will start to get radical on me and i have to shut it down. What ive found out is when i cover the back of the left side carb(no filters on it yet)it starts to die out-----when I cover the right side carb intake it starts to rev to the moon(fast) then its out of control and I will hit the kill switch...????????Why is it doing this???Please help , Thank you in advance. Quote Link to comment Share on other sites More sharing options...
SheezFast02 Posted July 11, 2011 Report Share Posted July 11, 2011 (edited) Sounds like you have an airleak. I just went through this on a kid's Blaster I'm working on. It had a major airleak right at the reed cage that I remedied with some RTV. I've aso heard of this happening when one carb isn't getting adequate fuel delivery. You may be told by the more experienced jetting gurus to go up a little bigger on your pilot jets, as 42's seem a little on the lean side. I'm running 45's and I'm at 300ASL, without timing advance or coolhead. First thing I'd do is a leakdown test, then bump up the pilot a couple sizes and work my way down from there. Always start rich, then lean it out little by little to dial it in. Edited July 11, 2011 by SheezFast02 Quote Link to comment Share on other sites More sharing options...
421alkybanshee Posted July 11, 2011 Author Report Share Posted July 11, 2011 Well I just found out that one of my two brand new carbs had a smaller main jet in it..... the side that would rev up when i would put my hand on the carb to choke it out had a 135 main jet, where the other side had a 140 jet in it. So im pretty sure this is a good part of my problem. Im gonna order jets and pilots tomm. But does ANYBODY know about these LG N needles? should I order somthing different? Quote Link to comment Share on other sites More sharing options...
SheezFast02 Posted July 11, 2011 Report Share Posted July 11, 2011 Your main jet shouldn't cause any issues with your idle. Your idle is controlled by your pilot jet/air screw. Again, I suggest you start with a slightly bigger pilot jet and make sure the air screws are backed out the same amount on both carbs. I'm also assuming your carbs are not synchronized. Do some reading on carb sync. I highly recommend you get the sync tool from Jeff at FAST Racing. You'll be glad you got it. Also, have you checked to see if the idle screw isn't in too far, causing your slide to stick open? This has to be either an airleak or something minor going on within your carbs. Be very thorough and you'll figure it out. Quote Link to comment Share on other sites More sharing options...
camatv Posted July 11, 2011 Report Share Posted July 11, 2011 everytime you put your hand over the carbs and "rev to the moon" you are hurting the hell out of your motor. you better figure it out or your gonna blow it up. are both carbs slides hutting all the way? get the bike to run but not IDLE AT ALL THEN SET YOU IDLE WITH A SYNCH TOOL oops sorry. clean the carbs, call SUDCO and ask them what needles they recomend and make sure you have REAL pwk's adn not the OKO's if you have the shit chinese knock off's your also fuel starving if not having problems with cheapo carbs.. a leak down test would also be a good idear. Quote Link to comment Share on other sites More sharing options...
421alkybanshee Posted July 11, 2011 Author Report Share Posted July 11, 2011 everytime you put your hand over the carbs and "rev to the moon" you are hurting the hell out of your motor. you better figure it out or your gonna blow it up. are both carbs slides hutting all the way? get the bike to run but not IDLE AT ALL THEN SET YOU IDLE WITH A SYNCH TOOL oops sorry. clean the carbs, call SUDCO and ask them what needles they recomend and make sure you have REAL pwk's adn not the OKO's if you have the shit chinese knock off's your also fuel starving if not having problems with cheapo carbs.. a leak down test would also be a good idear. These werent knock offs. I purchased from parts unlimited, they are 29 pwk's. They were $400 bucks Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted July 11, 2011 Report Share Posted July 11, 2011 pressure test!!!!! Quote Link to comment Share on other sites More sharing options...
421alkybanshee Posted July 11, 2011 Author Report Share Posted July 11, 2011 pressure test!!!!! how do you do that? is there more tools i need? Quote Link to comment Share on other sites More sharing options...
421alkybanshee Posted July 13, 2011 Author Report Share Posted July 13, 2011 I did a leakdown test, thank you to the guys who showed how to make one. I made one and only lost less than 1/2 lb in six minutes time. I now know that its a carb issue so ive ordered a few different pilots and mains to start jetting the carbs correctly. Quote Link to comment Share on other sites More sharing options...
421alkybanshee Posted July 16, 2011 Author Report Share Posted July 16, 2011 Blew carbs out completely, put 160 mains and 50 pilots and it idles nice, and runs really good. Plugs dont look to bad, maybe a tad on light side but not by much at all, any suggestions on how I should richen up a tad? Thanks for all your help, It was much appreciated from the homemade leakdown tester, to the purchase of these 28 pwk's to the jetting. It all worked out pretty good so far. Everyone have a safe and great weekend-----ride fast and hard!!! Quote Link to comment Share on other sites More sharing options...
camatv Posted July 16, 2011 Report Share Posted July 16, 2011 162-165 mains. just get a few more and play with it! dont be afraid to just experiment. thats how jetting is done get a handfull of jets and just keep trying differnt setups till its right after you have it idleing and revving good you can start messign with mains.. a tad rich on top is not going to kill it and it shouldnt foul pulgs much if ever when you have it right. Quote Link to comment Share on other sites More sharing options...
421alkybanshee Posted July 17, 2011 Author Report Share Posted July 17, 2011 Ok, runs good, a little studder while your riding when i go from running at a constant speed to stabbing the gas??? it comes out of that and runs hard, like i said that isnt terrible, it idles good, but when i shut it off it wont start unless i change the plugs???????why? Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted July 19, 2011 Report Share Posted July 19, 2011 (edited) How are you riding before you shut it down? Are you shutting fuel off? Also, what throttle posistion are you at when you stab it? Edited July 19, 2011 by Larry's Shee Quote Link to comment Share on other sites More sharing options...
421alkybanshee Posted July 19, 2011 Author Report Share Posted July 19, 2011 riding like normal, cruising down the road, rippiing on it going down my lane on my 80 acre farm, then just shutting it off, no i didnt shut fuel off until im done riding, and throttle position would be 1/4 or a little past to wide open. I figured i would go down 1 more pilot jet(started at 42-too lean) went to 50 (once shut off i had to change plugs to start) now at 48 pilots and it takes a few kicks but it will start for the most part. I figured i would try I think the next step down is 45 or 46 and see if it kicks over better, and if that doesnt help then maybe I should buy a CDI box and start over Quote Link to comment Share on other sites More sharing options...
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