Dave G Posted March 24, 2012 Report Share Posted March 24, 2012 First off, let me apologize for this being such a long post.....but I figure if you guys don't know everything, then you can't help. With that said....here is what I have. The project Banshee I have been working on is built and does run.....sorta. Yesterday, I had it running, and it bogged just off idle, but then picked up. If it cut off, it would fire right back up. However, it didn't smoke at all, and got very hot, very fast.. I realized I was running lean, and shut it down. I pulled the engine again to verify no damage to the pistons or cylinders....and luckily it was ok. During the process of pulling it out, I found the lean condition. I had forgotten to put the choke tube in between the carbs. I also pulled the carbs apart and checked every orifice, float height, etc. I read an article last night about jetting, and I have removed the snorkel, added a K&N filter, and have a 2 into one exhaust. From everything I gathered there, I figured I needed to jet up to a 320 main. I think I was wrong. lol I put everything back together today, including the choke tube this time, and fired it up. Well, eventually. Choke appears to make no difference what so ever. The only way to get it to start is to hold something over the carb intakes to cause it to suck massive amounts of fuel in. Then it will start relatively easily, and you have to remove the blockage from the carb intakes so it can then get air. It will not idle at all, and after about 3 seconds of throttle manipulation to keep it running, it dies out. It smoked plenty....probably too much. I then went to 280 mains, but have the same exact thing going on as the 320's. Choke still seems to make no difference, and it won't start unless you have the airbox side of the carbs blocked off in some way. Even if the engine is warm. The carbs are synced, I have adjusted the air screw from seated to 4 turns in various graduations. I've both enabled and disabled the TORS. I've checked and rechecked everything more times than I can count. I'm lost..... The specs right now are: 280 mains 25 pilots 3rd notch on needles I REALLY don't want to take is to the local Yamaha dealer and have them fix it, because they are ridiculously expensive, and I would rather be able to fix it myself anyway so I can have a better understanding of things. I'm thinking it has to be jetting, because I have checked everything else, and everything else is good! Any help is GREATLY appreciated! Dave Quote Link to comment Share on other sites More sharing options...
XxlongshotxX Posted March 24, 2012 Report Share Posted March 24, 2012 Turn your air screws all the way in, then turn them out a half a turn, sounds like your runnin lean. If that doesn't work then go up a size or two on your pilot. Quote Link to comment Share on other sites More sharing options...
Dave G Posted March 24, 2012 Author Report Share Posted March 24, 2012 1332626666[/url]' post='1326323']Turn your air screws all the way in, then turn them out a half a turn, sounds like your runnin lean. If that doesn't work then go up a size or two on your pilot. I have tried that, and was thinking the pilot may be too small.....but would that cause the starting issues? Quote Link to comment Share on other sites More sharing options...
toytech Posted March 24, 2012 Report Share Posted March 24, 2012 I have tried that, and was thinking the pilot may be too small.....but would that cause the starting issues? yes to small of pilots will make it start very hard Quote Link to comment Share on other sites More sharing options...
Dave G Posted March 24, 2012 Author Report Share Posted March 24, 2012 Any size recommendation? 30's maybe? Quote Link to comment Share on other sites More sharing options...
Dave G Posted March 25, 2012 Author Report Share Posted March 25, 2012 Also, I am guessing that because the engine won't maintain running at any throttle, I will first have to get the pilot set to where it will idle and run slightly off idle, then the needle so I can get half throttle, and finally the main so I can get WOT. Am I correct in saying this? Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted March 25, 2012 Report Share Posted March 25, 2012 http://bansheehq.com/forums/index.php?showtopic=99361 Start by searching this thread for a simular set-up or search the whole jetting forum. Do you have a linc to the "article" you read? Was this set-up ever running or is this something you're just getting together? When tuning it has to be just like you plan on running it. Can't have air cleaner off and expect to get anywhere. Do you have correct bowl on the left carb? It has a small "BB" on the front. Are slide cutaways facing the air cleaner, slides can go in wrong carb backwards. Stock pilot is 25, try a 27.5 next with air screw 1 1/2 turns out. Double check float height. Have you done a leakdown test on it? Also might consider checking you water pump that it is operating properly. Quote Link to comment Share on other sites More sharing options...
Dave G Posted March 25, 2012 Author Report Share Posted March 25, 2012 1332637185[/url]' post='1326363']http://bansheehq.com...showtopic=99361 Start by searching this thread for a simular set-up or search the whole jetting forum. Do you have a linc to the "article" you read? Was this set-up ever running or is this something you're just getting together? When tuning it has to be just like you plan on running it. Can't have air cleaner off and expect to get anywhere. Do you have correct bowl on the left carb? It has a small "BB" on the front. Are slide cutaways facing the air cleaner, slides can go in wrong carb backwards. Stock pilot is 25, try a 27.5 next with air screw 1 1/2 turns out. Double check float height. Have you done a leakdown test on it? Also might consider checking you water pump that it is operating properly. This set up has never run. It's probably 6 Banshees rolled into one. The site I got the info from was http://www.dfn.com/agservices/jetfaq.html All the above mentioned things I have verified. Floats are at 21mm, bowls are on right, slides are right. Quote Link to comment Share on other sites More sharing options...
Dave G Posted March 25, 2012 Author Report Share Posted March 25, 2012 I am thinking I may have some other problem(s). I went to the link you suggested, and found one identical setup to mine, and another very close.....and they are both running fine. Same altitude, same temp, same jets. What else could cause this if it isn't carbs?And I have not done a leak down test....... Quote Link to comment Share on other sites More sharing options...
fastbanshee8 Posted March 25, 2012 Report Share Posted March 25, 2012 Get some 27.5 pilots, and put them in. No two motors are exactly the same, and your hard starting is a big give away, that it's too lean. Quote Link to comment Share on other sites More sharing options...
AKheathen Posted March 25, 2012 Report Share Posted March 25, 2012 gee, if there was only some sort of section in this forum that adressed specifically jetting a banshee, that would be awesome, 'eh? anyways, altitude and temp in ferinheight will be a great help, also if you happen to be running other than premium unleaded pump gas. i would have to say, on average, your setup will be pretty close with 27.5, and 280. if there is a pilot jet installed under a 70, or so, it should start with the choke and 1-3 kicks. otherwise, there is another problem. make sure the choke carb has the jet in the bowl, and not on the right carb. make sure there is no airleaks on the engine side of the carbs. make sure the float needle/seats do not leak. Quote Link to comment Share on other sites More sharing options...
Dave G Posted March 25, 2012 Author Report Share Posted March 25, 2012 gee, if there was only some sort of section in this forum that adressed specifically jetting a banshee, that would be awesome, 'eh? anyways, altitude and temp in ferinheight will be a great help, also if you happen to be running other than premium unleaded pump gas. i would have to say, on average, your setup will be pretty close with 27.5, and 280. if there is a pilot jet installed under a 70, or so, it should start with the choke and 1-3 kicks. otherwise, there is another problem. make sure the choke carb has the jet in the bowl, and not on the right carb. make sure there is no airleaks on the engine side of the carbs. make sure the float needle/seats do not leak. I apologize.....I didn't realize there was a dedicated jetting section. I'm new here. Anyway, I'm at 800 ft altitude, and around 70-75 degrees. A buddy of mine has a Banshee as well, and this morning he let me try both 27.5 and 30 pilots. Same thing. Won't start unless pouring gas into either the carb intakes or spark plugs. Then it will only run until it burns out the gas I dumped in. That same buddy is saying it sounds like I have a leak in the crankcase, and that I should have used a high pressure sealant like Hondabond instead or High Temp RTV. ????????? Quote Link to comment Share on other sites More sharing options...
slothman Posted March 25, 2012 Report Share Posted March 25, 2012 Won't start unless pouring gas into either the carb intakes or spark plugs. Then it will only run until it burns out the gas I dumped in. This is definitely a no-fuel issue. Either one of the jets is plugged up, or one of the hoses is swapped. I would take apart the carbs and inspect every nook and cranny. Tripple check all of your work, and take your time. It's definitely not getting fuel from the carbs causing a lean condition. Are you installing brand new jets, or used ones ? Quote Link to comment Share on other sites More sharing options...
lms1977 Posted March 25, 2012 Report Share Posted March 25, 2012 if it is a dynoport 2 into 1 pipe your mains are probably way to big I have the install sheet in the garage I think they tell you not to rejet?? have you checked the reeds ?? also what compression does it kick to on the gauge Quote Link to comment Share on other sites More sharing options...
Dave G Posted March 25, 2012 Author Report Share Posted March 25, 2012 if it is a dynoport 2 into 1 pipe your mains are probably way to big I have the install sheet in the garage I think they tell you not to rejet?? have you checked the reeds ?? also what compression does it kick to on the gauge Reeds are ok. I double checked them. Carbs have been pulled down multiple times, checked and rechecked, and checked again. All jets are new and clear. All nooks and crannies in carbs are clean. Compression is 60 psi single kick, and builds to 110-115 with multiple kicks. Quote Link to comment Share on other sites More sharing options...
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