tuck1371 Posted March 13, 2012 Report Share Posted March 13, 2012 First off, my setup... Coolhead w/21cc domes .080 overbore unknown port work Toomey T5 K&N Filter in stock box w/no lid Stock carbs w/TORS removal Elevation ~1300-1400' Bought my banshee a couple weeks ago, guy didn't know much about it. Tore it down, learned it should've been running better fuel than what the pump had to offer and set it back up to (hopefully) pump gas specs. I also rebuilt the carbs in the process. Anywho, I got inside the carbs and found 270 mains and 25 pilots. Thought it might be a little under-jetted and got to researching. Found main jetting reccomendations from 310-340 and 27.5 pilots on somewhat similar setups. Talked to a local shop and he recommended running a 340 main... So here's where it gets fun... The carb kits came with new needles (the ones in the slider), but they were a little shorter than the originals I took out. Put it all back together with the new needles, 340 mains and 27.5 pilots, got it to fire once and then nothing. I could kick and kick and kick all day long and it wouldn't do anything. Smelled the fuel, got plenty of spark and no lack of air. Pull a plug, reeks of fuel. So I take a lighter, warm over the end of the plug, and try it again. Kick and it stumbles. Kick again and nothing. Do this a couple times. I figure it's flooding/fouling. Talked with a buddy and we decided to put the original (longer) needles back in on the middle groove. Got it back together, kicked and got it to fire and idle for a little bit before the bowls ran out of fuel. Put some more fuel in the bowls, kick and nothing. I pull the plugs and this time they don't reek of fuel, but I can still kind of smell it. Took the lighter to the plugs again and got a kick and stumble. So I typed all that for this question... Are 340 mains too big for my setup and causing me to flood/foul out my plugs? Would I be better off stepping the mains down a little? Tomorrow night I might try adjusting the needles a bit more and see if it helps, but I'm also thinking about stepping down to a 310-320 main (like I probably should've done in the first place) when I can get to town and buy some more. Somewhat longwinded, I know. Sorry about that. Just a little frustrated... I'm gonna go find a frosty beverage of the alcoholic variety (no shooting the shee just yet). Please feel free to offer any advice. Thanks! Quote Link to comment Share on other sites More sharing options...
Titan up Posted March 13, 2012 Report Share Posted March 13, 2012 (edited) the main jets only come into play from 3/4-full throtttle, when the bike is actually running. What do you mean it idled until the bowls ran dry and then you put more fuel in the bowls?? Do you have the tank attached with the petcock on? Are your floats adjusted to spec? Edited March 13, 2012 by Titan up Quote Link to comment Share on other sites More sharing options...
tuck1371 Posted March 13, 2012 Author Report Share Posted March 13, 2012 Thanks for the reply. Yeah, I had the tank off of it when I finally got it to fire up. At that point I thought I had it figured out so I put the tank back on (petcock on) and then it wouldn't start again. The floats are as they were before I started messing with it, but as to spec I couldn't tell ya. It was a one to two kicker to start before. Guess I should probably buy the Clymer's for that, have to wait til payday though. What are the screws on the airbox side of the carb, left side? Mixture screws? When I put it back together I backed those off 2 turns from bottomed out (what they were before I started anything)... Could that be causing it as well? Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted March 13, 2012 Report Share Posted March 13, 2012 Not trying to be rude, but did you drive the banshee before you started messing around with it? YOu did waaay to many changes at once.... 1 thing i have learned with my banshee, snowmobile and drag car. One change at a time. No matter what. Your gunna be chasing you tail now... Why do you think that set up isnt meant for pump fuel? 21cc domes arent that crazy on a stock engine size. Quote Link to comment Share on other sites More sharing options...
special06shee Posted March 13, 2012 Report Share Posted March 13, 2012 Not trying to be rude, but did you drive the banshee before you started messing around with it? YOu did waaay to many changes at once.... 1 thing i have learned with my banshee, snowmobile and drag car. One change at a time. No matter what. Your gunna be chasing you tail now... Why do you think that set up isnt meant for pump fuel? 21cc domes arent that crazy on a stock engine size. I agree 100 percent.. You might feel like your accomplishing twice as much by swaping out 2-3 things at a time but actually most of the time your just making 4 times the headache!! One thing at a time. As far as the domes i ran 20cc and had no problem with pump fuel(93) Quote Link to comment Share on other sites More sharing options...
tuck1371 Posted March 13, 2012 Author Report Share Posted March 13, 2012 no offense taken.. It had 19cc domes in it when I got it and plugs were backing out on me. Talked to john at jsr performance in wichita and he said that the plugs were most likely backing out because of detonation. I went with 21cc domes just to make sure i'd be safe on 91 octane. As far as jetting, it had 270s in it and just from researching on here and elsewhere on the web, similar setups were running bigger mains then that. jsr recommended a 340 main so thats what I went with. I did ride it beforehand but just enough to make sure it went through the gears before I had a plug back out. Quote Link to comment Share on other sites More sharing options...
Titan up Posted March 13, 2012 Report Share Posted March 13, 2012 Go ahead and put the tank on and run the fuel lines like normal with the petcock on. The bowls need to be full of fuel at all times. The amount of fuel in the bowls at any giving time will effect jetting (vacuum related)....I can almost guarantee that's your problem....just trying to start it, your probably running the bowls dry...The 340 mains might be a couple sizes too big, but that wont effect the starting, you can dial that in later. Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted March 13, 2012 Report Share Posted March 13, 2012 Oh ok, ya 19cc domes on 91octane is the EXXtreme limit. Well all i can say, if your having trouble. JUst be patient with your jetting. Start with pilots. Get it starting easy when stone cold. Then move to your needles and mains. IT will take a long time to get it jetted perfect. But you ll get their. GOOD LUCK MAN!! Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted March 13, 2012 Report Share Posted March 13, 2012 ALSO a hint. Try new plugs. Once you foul a set of NGK's. They are never right after.... Gap them at .030-.025. Quote Link to comment Share on other sites More sharing options...
tuck1371 Posted March 14, 2012 Author Report Share Posted March 14, 2012 I really appreciate all the replies and advice. Didn't get a chance to get to it tonight, but after work tomorrow I'm going to be hellbent on getting it to start like it used to. Game plan is in place. I do have one question though... could improper Air Screw adjustment be causing me to flood out? I read that from idle to 1/4 throttle is where the air screw comes into play... I'm thinking about starting there and seeing what that does. I'll let ya know how it goes and what I figure out. Until tomorrow... Quote Link to comment Share on other sites More sharing options...
tuck1371 Posted March 17, 2012 Author Report Share Posted March 17, 2012 I got it figured out! I feel like a dumbass, but I'll share what it took to fix... So the other night, I played with air screw adjustments, putting the smaller jets in and out, messing with idle screws, yada yada yada... couldn't get it to start. Went over to JSR Performance in Wichita and talked to John about what was going on. He thought about it a little and said "You got your carb slides in the right way?" I'm sure I had a pretty good impression of a deer trapped in headlights at that point in time. I said "I dunno." He told me to check it, because that sounded like what was going on. Got home and checked... sure enough they were in backwards. Sooo... a little more tinkering, a new set of plugs, and getting any excess fuel out that I could and I now have a banshee that will start repeatably. So stoked! I'm definitely still a newbie to the banshee world, but I'm learning as I go. Now I need to get it dialed in and go play! Quote Link to comment Share on other sites More sharing options...
Titan up Posted March 18, 2012 Report Share Posted March 18, 2012 Ahhhh thee ol' slides in backwards trick....Glad you got it fingered out and props to you for coming back and finishing/putting closure to your thread..So many peeps ask questions to never return. Quote Link to comment Share on other sites More sharing options...
bluebanshee98 Posted March 18, 2012 Report Share Posted March 18, 2012 do you have port work done or your not sure? my 4 mil stroker with a hjr full dune port i am currently running 320 mains in stock carbs with 27.5 pilots, fmf pipes, k&n air filter in air box with lid on. i def dont think you need 340... whats the temp right now that you'll be riding in? mine is running great now at temps 40+. so when its 80+ ill prob drop down another jet. ( i still need to do a plug chop to make sure im 100%) before i went 4 mil with a full port job i had pipes, k&n in box with lid off, stock carbs with 270 mains and 25 pilots. in the summer it ran great. once the temp dropped down alot i had to bump it up to 300's and put the lid back on. if you have some kind of port work done throw some 300's in there and see how it runs. if it runs good with no problems ( pulls hard and no seizure at top end of powerband then your prob almost dead on. only way to tell for sure if your running to lean or rich would be to do a plug chop Quote Link to comment Share on other sites More sharing options...
tuck1371 Posted March 18, 2012 Author Report Share Posted March 18, 2012 I got the 340s out of it... Still running the 25 pilots because I didn't have access to the right sized screw driver to get em out but I did put in some 310 mains. Went out and rode a little today and it definitely sounds good but found I've got some BAD clutch slippage going on so I can't see how she reacts under load. I'll go research that a bit and see what I can get figured out there. I'm pretty sure it's ported, but as to the extent I don't really know. The runners into the cylinders definitely have alot of material taken off of them but I haven't got the urge to pull the jugs and find out the extent. One day, maybe. Before that though, I plan on doing a plug chop once I get the clutch issue resolved to make sure my jetting is dialed in. Temps right now are probably 60-70. Summer will get over 100... but again, I'll worry about that beast when it gets here. Thanks again for all the help! Quote Link to comment Share on other sites More sharing options...
EvilBanshee Posted March 18, 2012 Report Share Posted March 18, 2012 LOL iv done that before.... It happens! MY first build with new carbs. The bikes dont run to well when the slides are in backwards.. Quote Link to comment Share on other sites More sharing options...
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