gorethrasher Posted February 23, 2009 Report Share Posted February 23, 2009 Completely stock banshee- recently rebuilt top end When I ride, after about 10 mins riding it starts bogging down and you need to keep it in powerband to get any power. Then the left side starts to backfire getting worse till there is barely any power. It seems to have more power using 1/4 - 1/2 throttle since it bogs down under full throttle. When I check the plugs, the left side is fouled up and the right side is perfect. I have checked the sync on the carbs and got them perfect, I also cleaned all the gunk out of the carbies, they are like brand new. I am running stock jets and set them how I always have em. Compression is 115 both sides. I have thought about air leaks, but it's not running lean. It could be some kind of ignition problem, but it's only on one side. So I thought it's sucking air from the crank seal, I took the flywheel cover off and there doesn't seem to be any leaks, and with all that backfiring It would be obvious. I will try another set of coils and maybe a different stator, I could also try pressure testing the crank. I took the carbies out again and am going to jet up the main to see if it stops bogging down under full throttle. It's been quite frustrating since it ran so well after the rebuild and it suddenly doesn't run. Any other ideas? Quote Link to comment Share on other sites More sharing options...
Klaus Posted February 23, 2009 Report Share Posted February 23, 2009 Hey man. Mine did the same, float levels were too low - which caused surging, check the air fuel - stopped the backfiring, then it was fine. Just check your float levels and float bowls - make sure float bowls are not they not switched around. Then check the choke circuit, check the o ring on the plunger, check that the plunger works fine etc. The choke tube connecting the 2 carbs, is it in place? Oh yes, check that the slides are in the right way too. These are only some ideas, all are basic, but sometimes we overlook the easier stuff, I'm not a professional - haha. Quote Link to comment Share on other sites More sharing options...
01banch Posted February 23, 2009 Report Share Posted February 23, 2009 I am pretty sure tors have the ability to make it act up as well check the parking brake and make sure it is completely disengaged at the handlebars. Quote Link to comment Share on other sites More sharing options...
gorethrasher Posted February 24, 2009 Author Report Share Posted February 24, 2009 I changed the main jets to #210 from the stock #200, I also checked the choke and floats on the carbies. So I took her for a run, let it warm up with the old plugs, it wasn't running very well. I changed out the plugs when it was warm, it felt a bit better but backfired once or twice. I turned out the pilot screw 1/4 turn and tried again, this time it had more grunt lower down, so I got excited doing burnouts for a bit, it started to feel lean and it was revving high. I pulled up next to the car and it was boiling over. I take the seat off and find that one of the carbies tops have unscrewed and come off, so that was causing it to go lean. I put it back together and make sure it's tight. Also richened the pilot another 1/4 turn. It was feeling better then before, less backfiring but still only drivable in the 1/4 - 1/2 throttle range. Unfortunately I ran out of fuel on the last run. The plugs are looking way better now too. So im going to go one more size up on the main jet and see how that effects things. Quote Link to comment Share on other sites More sharing options...
Klaus Posted February 24, 2009 Report Share Posted February 24, 2009 What size are your pilots? Quote Link to comment Share on other sites More sharing options...
AKheathen Posted February 24, 2009 Report Share Posted February 24, 2009 are you still running a snorkel? have you tried raising the needles one clip? Quote Link to comment Share on other sites More sharing options...
gorethrasher Posted February 24, 2009 Author Report Share Posted February 24, 2009 Pilots are 27.5 I forgot that I am running a k&n filter too. I just took it for some bog laps around the park, up to 1/2 throttle it's running sweet. enough power to do big drifts, above 1/2 and it bogs down, so Im gonna get some bigger main jets tomorrow and try again. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted February 24, 2009 Report Share Posted February 24, 2009 Pilots are 27.5I forgot that I am running a k&n filter too. I just took it for some bog laps around the park, up to 1/2 throttle it's running sweet. enough power to do big drifts, above 1/2 and it bogs down, so Im gonna get some bigger main jets tomorrow and try again. depending on your elevation and temp, your mains should be around 240-260 without a lid. Quote Link to comment Share on other sites More sharing options...
gorethrasher Posted February 25, 2009 Author Report Share Posted February 25, 2009 depending on your elevation and temp, your mains should be around 240-260 without a lid. I got some 230 and 250 jets to try today. I took the bike out again with the 230 jets, colder then usual weather (was actually raining). Started and ran fine, full throttle was still a bit boggy, after about 10 mins she started feeling worse and started backfiring again. Left plug is black. I brought her home and put the 250 jets in, took it for a run at the park for about 5 mins, full throttle was getting better but still not as strong as before. After the short ride the plugs looked ok. I will try again when the weather is a bit warmer and see how it runs with the 250 mains. Should I be adjusting the pilot screw after putting bigger mains in? Quote Link to comment Share on other sites More sharing options...
gorethrasher Posted March 5, 2009 Author Report Share Posted March 5, 2009 Still not having any success with the bike. I put some 270 jets in, checked the carb sync and made sure the pipes were sealing properly. Full throttle is much better, hitting powerband and revving out, but it gets to a certain rpm and it feels like it has a rev limiter on it. Once again after 10-15 mins riding the left side starts backfiring and it has no power when not in powerband and the left plug is black while the right side is a golden brown. I am going to start swapping parts from my friends bike, starting with the ignition coil and then the stator. Any other suggestions? Quote Link to comment Share on other sites More sharing options...
Klaus Posted March 5, 2009 Report Share Posted March 5, 2009 Still not having any success with the bike. I put some 270 jets in, checked the carb sync and made sure the pipes were sealing properly. Full throttle is much better, hitting powerband and revving out, but it gets to a certain rpm and it feels like it has a rev limiter on it. Once again after 10-15 mins riding the left side starts backfiring and it has no power when not in powerband and the left plug is black while the right side is a golden brown. I am going to start swapping parts from my friends bike, starting with the ignition coil and then the stator. Any other suggestions? Check your air/fuel screws. Turn them in to seat lightly, then turn them out 1 turn, the bike should be warm for this. Set the idling up a bit, Then turn one out very slowly until the revs pick up, do the same with the other cylinder. Then go back to the first one and do then same again, the Shee should be almost perfect when it idles at the highest rpm point. So when the revs don't pick up any more, you should be good. Give it a shot. Afterwords just set your idling back to normal. Thats how I tune my bike, works for me. According to spec it should be around 1.5-2.0 turns out, may vary depending on if pilots are too rich or too lean. Mine also backfired, but I just tweaked the air fuel screws, ran like a dream after that. Quote Link to comment Share on other sites More sharing options...
Klaus Posted March 5, 2009 Report Share Posted March 5, 2009 The other thing you can try, swop your plugs, If that doesn't work, swop your plug leads around, see if the problem moves to the other cyl, then it is spark related, my bet is on the air fuel. What plugs are you running btw, they not perhaps too cold? Oh and the needles on the slides should be on the middle clip, groove nr3 ( from top or bottom doesn't matter) Quote Link to comment Share on other sites More sharing options...
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