BellicoseBanshee Posted July 3, 2008 Report Share Posted July 3, 2008 Hi There, I'm struggling with a bottom-end bog on my stock '06. Any advice is appreciated. The bike is completely stock, with the exception of the TORS removed. (200 main jets, needle in 3rd position, etc.) - Bike starts first kick - Has bogging feel when revving - When I take it out and open it up it seems o.k. - not exactly crisp, but it cleans itself out. - Carbs are sync'd - Floats set - Idle screws are set, but I need to grind the carb body down flat, so they will reach in. (took out the jamb nut so that I could see how the bike ran in the interm) - Stock jetting, needle, air screw - 2 turns out, etc., - Running a synthetic shell oil @ 40:1 - br9 plugs, will be picking up br8 today. In summary, I basically verified everything is at the factory settings. I had thought it would run fine. I must be missing something. Thanks! First off, the factory jetting is not always correct. The factory oil ratio is 24:1. You are running 40:1, which will richen the jetting. Sounds like everything else is as it is supposed to be, so I would plug chop the mains. When the main jets are as they should be, then start working the needle. When the needle is correct, then you can make final air screw adjustments (which they should be with stock exhaust). I would go with BR8ES plugs as well. How are you setting the air screws? This is how to do it: Turning the air screw clockwise reduces the amount of air and turning the air screw counter-clockwise increases the amount of air in the pilot system. Warm up your engine, then adjust the idle slightly higher than normal. Turn the airscrews in until they seat and then back them 1/4 turn and let the engine stabilize. Keep turning the airscrews out a 1/4 turn at a time, allowing the engine time to stabilize between changes, until the engine reaches its highest RPM. The air screws should be between 1 and 2-2.5 turns out. If the highest RPM is less than 1 turn (lean), install a larger pilot jet. If the highest RPM is more than 2-2.5 turns out (rich), install a smaller pilot. If you are going to spend time jetting your bike, might as well throw an exhasut system on, timing plate, filter(s), and Noss head (or shave the stock head)! :biggrin: Also, if you have not done so, make sure the carbs are clean, and all the passages are not plugged after installing the idle screws... THIS link has some good information about jetting. It covers Keihin carbs, but the concepts are still the same for Mikuni. Quote Link to comment Share on other sites More sharing options...
05.Banshee.SE Posted July 3, 2008 Report Share Posted July 3, 2008 I think we already troubleshooted the jetting and air screws? Quote Link to comment Share on other sites More sharing options...
doug Posted July 3, 2008 Author Report Share Posted July 3, 2008 First off, the factory jetting is not always correct. The factory oil ratio is 24:1. You are running 40:1, which will richen the jetting. Sounds like everything else is as it is supposed to be, so I would plug chop the mains. When the main jets are as they should be, then start working the needle. When the needle is correct, then you can make final air screw adjustments (which they should be with stock exhaust). I would go with BR8ES plugs as well. How are you setting the air screws? This is how to do it: Turning the air screw clockwise reduces the amount of air and turning the air screw counter-clockwise increases the amount of air in the pilot system. Warm up your engine, then adjust the idle slightly higher than normal. Turn the airscrews in until they seat and then back them 1/4 turn and let the engine stabilize. Keep turning the airscrews out a 1/4 turn at a time, allowing the engine time to stabilize between changes, until the engine reaches its highest RPM. The air screws should be between 1 and 2-2.5 turns out. If the highest RPM is less than 1 turn (lean), install a larger pilot jet. If the highest RPM is more than 2-2.5 turns out (rich), install a smaller pilot. If you are going to spend time jetting your bike, might as well throw an exhasut system on, timing plate, filter(s), and Noss head (or shave the stock head)! :biggrin: Also, if you have not done so, make sure the carbs are clean, and all the passages are not plugged after installing the idle screws... THIS link has some good information about jetting. It covers Keihin carbs, but the concepts are still the same for Mikuni. Is it not fair to think that the factory settings will ensure the bike runs well? Not necessarily great, but at least well? 40:1 is a lot leaner than 24:1, so I had expected the bike to not have a problem with rich fuel. I'll adjust the air screw again, do you think it could be causing the problem of bog/richness? Thanks. Quote Link to comment Share on other sites More sharing options...
BellicoseBanshee Posted July 3, 2008 Report Share Posted July 3, 2008 Is it not fair to think that the factory settings will ensure the bike runs well? Not necessarily great, but at least well? 40:1 is a lot leaner than 24:1, so I had expected the bike to not have a problem with rich fuel. I'll adjust the air screw again, do you think it could be causing the problem of bog/richness? Thanks. The factory jetting may be close, it may not. I always start with the mains, and work my way down. If the mains are good, great, you can move on... Whenever you decrease the amount of oil in the fuel/oil mixture, it increases the amount of fuel in the fuel/air mixture. A rich or lean jetting condition is not determined by the amount of oil mixed with the gas, but determined by the amount of fuel mixed with the air coming in. If the engine is jetted incorrectly, cutting the oil in the mixture may improve performance, but a bike canbe jetted to run well mixed at 50:1 or it can be jetted to run well mixed at 20:1. It is all in the jetting... I am not a jetting expert, and without actually riding the machine, I can only offer the techniques that I use when correcting a jetting issue. Maybe the bogging has nothing to do with jetting, but if it were my bike, I would start with the mains, then go to the needle, then finalize the air screw. If the bog persists with reasonable changes in jetting, then I would look at something else. I am just giving advice, and could be wrong, but in my many years of experience with jetting LT250Rs, ATC250Rs, stock and ported Banshees, and Cub Banshees, the method I mentioned above has work well for me... Good Luck! :beer: EDIT: I do not use the above method when making minor changes on a good running bike, only when a problem persists... Quote Link to comment Share on other sites More sharing options...
doug Posted July 3, 2008 Author Report Share Posted July 3, 2008 Right on - thank you for the input. I believe my main jet is fine at 200 because when I'm going through the gears and giving it throttle it runs fine. So, I'll lean out the needle a notch and work with the air screw to see where that takes me. Appreciate the all the help. :smile: BTW: changed fuel to yamaha lube 32:1, made no difference. Also, took carbs off and inspected reed cages. Everything looks fine in there too. Lot's of paint that is peeling from inside the reed "chamber" leading to the pistons though. I thought this was a little weird, but must be factory as I can't imagine someone painted this. Did find one weird thing when doing a very detailed analysis of the carbs though. In one, where the fuel valve seats (the part attached to the floats), I found that the casting or body of the carb was very jagged and was not a perfect circle like the other. It was almost as though it wasn't formed properly. http://www.stackhousesolutions.com/img_4115.jpg (photo - poor quality, it's difficult to shoot that close, but this will give the idea) The other question I had was is it possible that an incorrect installation of the tors removal kit could cause this accessive fuel problem? (I'm thinking not likely, but I didn't install the kit, so I'm not sure....) Something else I thought of - is it possible the spark plug wires are switched and therefor throwing off the timing or something? Could you please tell me which cable is supposed to go to which side of the motor or if it even matters. Next photo being uploaded is me pulling out my hair. Quote Link to comment Share on other sites More sharing options...
doug Posted July 4, 2008 Author Report Share Posted July 4, 2008 Right on - thank you for the input. I believe my main jet is fine at 200 because when I'm going through the gears and giving it throttle it runs fine. So, I'll lean out the needle a notch and work with the air screw to see where that takes me. Appreciate the all the help. :smile: BTW: changed fuel to yamaha lube 32:1, made no difference. Also, took carbs off and inspected reed cages. Everything looks fine in there too. Lot's of paint that is peeling from inside the reed "chamber" leading to the pistons though. I thought this was a little weird, but must be factory as I can't imagine someone painted this. Did find one weird thing when doing a very detailed analysis of the carbs though. In one, where the fuel valve seats (the part attached to the floats), I found that the casting or body of the carb was very jagged and was not a perfect circle like the other. It was almost as though it wasn't formed properly. http://www.stackhousesolutions.com/img_4115.jpg (photo - poor quality, it's difficult to shoot that close, but this will give the idea) The other question I had was is it possible that an incorrect installation of the tors removal kit could cause this accessive fuel problem? (I'm thinking not likely, but I didn't install the kit, so I'm not sure....) Something else I thought of - is it possible the spark plug wires are switched and therefor throwing off the timing or something? Could you please tell me which cable is supposed to go to which side of the motor or if it even matters. Next photo being uploaded is me pulling out my hair. Update: I just spoke with the original owner of the bike and he told me that this is how the bike performed since he purchased. E.g., this is something that has been a problem - even before the TORS removal, etc. At this point, I bought another set of stock carbs I'm going to try.....I'm beginning to think these carbs have issues, as I mentioned up above. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted July 4, 2008 Report Share Posted July 4, 2008 Right on - thank you for the input. I believe my main jet is fine at 200 because when I'm going through the gears and giving it throttle it runs fine. So, I'll lean out the needle a notch and work with the air screw to see where that takes me. Appreciate the all the help. :smile: BTW: changed fuel to yamaha lube 32:1, made no difference. Also, took carbs off and inspected reed cages. Everything looks fine in there too. Lot's of paint that is peeling from inside the reed "chamber" leading to the pistons though. I thought this was a little weird, but must be factory as I can't imagine someone painted this. Did find one weird thing when doing a very detailed analysis of the carbs though. In one, where the fuel valve seats (the part attached to the floats), I found that the casting or body of the carb was very jagged and was not a perfect circle like the other. It was almost as though it wasn't formed properly. http://www.stackhousesolutions.com/img_4115.jpg (photo - poor quality, it's difficult to shoot that close, but this will give the idea) The other question I had was is it possible that an incorrect installation of the tors removal kit could cause this accessive fuel problem? (I'm thinking not likely, but I didn't install the kit, so I'm not sure....) Something else I thought of - is it possible the spark plug wires are switched and therefor throwing off the timing or something? Could you please tell me which cable is supposed to go to which side of the motor or if it even matters. Next photo being uploaded is me pulling out my hair. yamaha paints the cylinders inside and out. installing the tors removal kit incorrectly, won't make it draw more fuel. also, you can run it will either plug wire on either plug. it doesn't matter. Quote Link to comment Share on other sites More sharing options...
bansheesickness Posted July 4, 2008 Report Share Posted July 4, 2008 That's exactly how I feel.... This is insane. Should be very straightforward, factory settings, stock bike, I've never had this much trouble before. Thanks for your help. i remeber a few years ago myne did something similar to that and i found that the rubber hose that connects the two carbs together came off on one side. and also my other bashee was booging at low end and wouldnt clean out or run right at all and after allot of time and cusing trinty racing told me to check my stator it was an aftermarket one and the termails looked like they were ready to fall off. i was instructed to buy a stock stator and it fixed the problem. the parking brake switch also retards the ignition and makes simmilar effect Quote Link to comment Share on other sites More sharing options...
doug Posted July 4, 2008 Author Report Share Posted July 4, 2008 Did a compression test. No carbs on, reed cages removed, etc. Motor not warmed up and I got somewhere around 90 aside - definetly low, but I'm not sure how much of a difference it makes when warmed up, etc. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted July 6, 2008 Report Share Posted July 6, 2008 that's why its such a bitch to start. there'e no comp left to that motor. even though you are checking it cold, you should still pull 110-115lbs+. Quote Link to comment Share on other sites More sharing options...
doug Posted July 6, 2008 Author Report Share Posted July 6, 2008 Hi Guys - just picked up a stock set of carbs and installed them. Bike runs excellent. No trouble starting. The terrible bog is gone. I'm not sure if it was an incorrectly installed TORS removal kit or something with the carbs, but it's fine now. Thank you for your help. I'm not sure the compression tester is working properly because the bike starts no problem and hauls without any trouble. Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted July 7, 2008 Report Share Posted July 7, 2008 that's good to here that you've got it fixed. now take those shitty ass carbs and smash them with a sledge hammer, for all the grief they put you through:) Quote Link to comment Share on other sites More sharing options...
doug Posted July 7, 2008 Author Report Share Posted July 7, 2008 ROFL - no doubt. Do you think an incorrectly installed TORS removal kit would have done this? Quote Link to comment Share on other sites More sharing options...
mopar1rules Posted July 7, 2008 Report Share Posted July 7, 2008 i wouldn't think so. don't see what a guy could really fuck up during the install of a tors removal kit, to give you the tuning griefs that you've encountered. Quote Link to comment Share on other sites More sharing options...
05.Banshee.SE Posted July 8, 2008 Report Share Posted July 8, 2008 I don't see where you could install the kit wrong, and it ending up running rich and bogging. Quote Link to comment Share on other sites More sharing options...
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