RUNMYTA Posted September 1, 2004 Report Share Posted September 1, 2004 (edited) OK, I am about to burn my shee and shoot the service manager at local stealership. Here is the total story. 99 Shee, complete new topend less than 1 hour, cases split with new crank seals and bearings installed at the same time. Before the rebuild shee started running bad and acted like it was running on 1 cylinder. Also new reeds, and intake boots installed. All new gaskets through out. I have cleaned the carbs several times, checked for possible air leaks around the intake and base and head gaskets. No leaks found!! But runs lean on the right cylinder only!! **** Local stealership service manager (does all my transmission work at home dirt cheap) says that it has to be the center seal that is between the rods that is letting the air in or sucking the gas charge out of the right cylinder into the left. Some of you guys say that there is not a center seal!! Does anyone know for sure or have a microphisce to show the crank?? I know I need to try to do a leak down test, but where can you get the tools for this? TIA Mike Edited September 1, 2004 by RUNMYTA Quote Link to comment Share on other sites More sharing options...
pimp559 Posted September 1, 2004 Report Share Posted September 1, 2004 You buddy is blowing smoke up your ass. There is absolutely no seal between the crank inner bearings. You could have a leak between your case halves if the surface is messed up, not likely though. I'm assuming you have good carbs. Just because you cleaned the carbs a hundred times doesn't mean they are working right. After all the work you done to it, I would buy or borrow a set of carbs and see if that doesn't fix it. A used set of carbs is alot cheaper than a new top end. If you had a manuel you would see that there are no seals between the crank bearings. Quote Link to comment Share on other sites More sharing options...
banshee370 Posted September 1, 2004 Report Share Posted September 1, 2004 Again I will agree here... There is NO seal between the cank halves. Check this link to see http://216.37.204.202/Yamaha_OEM/YamahaATV...pe=13&A=138&B=3 First off do a compression check and a leak down test. What carbs are you running? Stock? What happened that caused you to split the cases? Crank go bad? Lose a piston? Give us a lil more info. Did you verify that your not having an ignition/electrical problem? Quote Link to comment Share on other sites More sharing options...
RUNMYTA Posted September 1, 2004 Author Report Share Posted September 1, 2004 B370, I had a wrist pin bearing let go and killed the left cylinder. So I had the cases split and cleaned out to make sure no metal was sucked into the crank case. While in there we put in new seals/bearings. I am running the stock carbs bored out to 27.5. I have switched the plug wires and still have the same effect. Plus if it was an ignition problem wouldn't the plug be fouled and wet? I have even pulled the stator cover off and sparyed WD-40 to see if it was sucking air there and it isn't. I am losing my mind F-ing with this thing Pimp, What could be wrong with the carbs?? There isn't to many moving parts that can go bad and everything looks good. Would the carb tops cause this?? Thanks,Mike Quote Link to comment Share on other sites More sharing options...
banshee370 Posted September 1, 2004 Report Share Posted September 1, 2004 Mike: Is one cyl lean/dead? If that one cyl is dead and dry then you have a carb problem. I had a similar problem and took the carb apart 50 friggin times....... I ended up having to soak the carbs in a cleaner, taking them completely apart and using an air gun on everything. Sometimes if the carbs sit long enough they will gum up and nothing will clean it out. (easily at least) How long was the bike apart? What is the bike doing now? Just running on one cyl? Any pops from the dead side? Does it feel like it wants to fire? I was at K&K yesterday and they were working on a blaster (bleh). It had all the symptoms of a lean condition. While poking around it, the carb top was leaking air and was partially the problem. The base gasket sucked in and caused the real problem..... So yes carb tops can be an issue. Give me some more info and I'm sure we could figure this out. Quote Link to comment Share on other sites More sharing options...
nater006 Posted September 1, 2004 Report Share Posted September 1, 2004 Dang man.. that sucks that yer having trouble. You should shoot that guy though.. there's definitely no middle seal! That guy is a cracker... sounds like he wants to split the cases for fun and a little cash. Quote Link to comment Share on other sites More sharing options...
BenBB Posted September 1, 2004 Report Share Posted September 1, 2004 Runmyta, did you try any of the stuff from the other thread that Forcefed, bigbore, and boonman suggested? From what you described in the other thread, it sounds alot like either the head gasket leaking into the cylinder or fuel starvation on the left carb as those guys suggested... Quote Link to comment Share on other sites More sharing options...
RUNMYTA Posted September 1, 2004 Author Report Share Posted September 1, 2004 (edited) OK, Now it gets even better.!!! I can switch the plug wires and the right cylinder still runs lean!! Well, this morning I pulled the left plug cap off the shee while running and it kept running on the right cylinder. Then I replaced the left cap and pulled the right plug cap off while running and shee died!! So I switched the plug wires to the opposite cylinder and the reverse of the above happened!!! I know the wire is getting spark because it bit me real good. The plug wire that is closest to engine is the one that killls the engine. What in the @$$@# is causing this? I have never seen anything so f-ed up before! Thanks for helping guys!! BenBB, I have tried everything except the leak down test ( i am in the process of getting a tester together). I don't think that the carbs are the problem (never know for sure) because I have cleaned them very extensively and my shee idles fine and pulls out OK, just when it gets under a heavy load is when it drops the right cylinder. No popping or anything, just loss of power and the right plug always showing very lean. As far as head gasket I am running a cool head and I have checked the coolant and it is full. B370, No both cylinders are hitting, just the right one falls of under load. I have some used tops that I was given that i am going to try today. The bike never sets more than 2-3 weeks with out a least being started and rode around my yard for a few minutes TIA,Mike Edited September 1, 2004 by RUNMYTA Quote Link to comment Share on other sites More sharing options...
Nighty Posted September 1, 2004 Report Share Posted September 1, 2004 Well I know that when the banshee sends out a spark it will send the spark to both sparkplugs. Meaning both plugs fire at the same time, 1 time when pistons are LOW and 1 time when pistons are high both at the same time. The sparkplugs shouldnt have anything to do with your right piston side beeing lean. But trying a new set wouldnt hurt. Are you sure your carb's are setup the same? same size pilots, mainjets. same needle height? When my pickupcoil went bad my banshee showed similar symptoms, but this sounds like something with air/fuel for the right side. Is your fuel petcock flowing o.k? under load your right carb might run out of fuel if the fuel flow is impeded or blocked or whatever. Quote Link to comment Share on other sites More sharing options...
BenBB Posted September 1, 2004 Report Share Posted September 1, 2004 You got gremlins man, try leaving a half-starved Rottweiler alone in the garage with your Banshee overnight, heh. Hmmm, coil maybe? A high-speed miss is a good symptom of a coil failure, best way to check it other than swapping it out is to take it to a shop to bench test it, perhaps you can talk that guy into checking it out at the dealership (just pull it off and take it in), while you're at it make sure the wires have a good connection at the cap & coil. Kind of a long shot given everything you've described but you never know (still doesn't really explain the lean cylinder). Good luck. Quote Link to comment Share on other sites More sharing options...
banshee370 Posted September 6, 2004 Report Share Posted September 6, 2004 Sorry for the late reply........... To me this sounds like an ignition problem. Have you tried closing the gap on your plugs to see if it helps? Do you have anyone that you can swap out CDI, Stator and Coil with? Now if your plug is bone dry, then your starving the cyl of fuel. I can switch the plug wires and the right cylinder still runs lean!! Well, this morning I pulled the left plug cap off the shee while running and it kept running on the right cylinder. Then I replaced the left cap and pulled the right plug cap off while running and shee died!! So I switched the plug wires to the opposite cylinder and the reverse of the above happened!!! I know the wire is getting spark because it bit me real good. The plug wire that is closest to engine is the one that killls the engine. What in the @$$@# is causing this? Now........ If your RIGHT cyl is lean and you pull the LEFT wire and it stays running, BUT when you pull the RIGHT wire the motor dies. That to me is an electrical/ignition problem. Have you done anything else recently to test/decipher what the problem is? Quote Link to comment Share on other sites More sharing options...
bigwill Posted September 6, 2004 Report Share Posted September 6, 2004 B370 is on point-Check coil and stator-when stators get weak-they wont fire both sides Quote Link to comment Share on other sites More sharing options...
RUNMYTA Posted September 6, 2004 Author Report Share Posted September 6, 2004 Both side of the coil are firing. I asked the Yamaha shop and they said that 1 lead was the dominant ground source for the coil and thay is why it acted funny by switching the plug wires around. While there I also asked my buddy the service manager to explain where he is getting the center crank seal from. So he pulled a service manual and showed me that between the center journals where the center bearing is that it is sealed between the cranks. He said he that he couldn't remember if it was an actual "removable seal" or a machined seal. Then another mechanic chimed in and said that it was machined onto the crank between the center bearings and if it was bad it would cause a lean cylinder. SO they both agreed that while the right cylinder is pressurizing on combustion stroke and the left cylinder is vacuuming on the intake stroke, it is pulling the fuel charge from the right cylinder and burning it in the left cylinder I also removed the complete intake system. I replaced reed cage gaskets, triple checked carb & reed boots, borrowed some new take off carbs from a buddy and replaced my carbs. Removed the tank cleaned the petcock, pickup hoses that go in the tank, cleaned the tank with fresh fuel, and replaced all of the fuel lines. Still the bike idles fine and when I put it under load it drops off the right cylinder and the plug is completely white with no signs of fuel! So I guess I am off to tear her down and replace the crank. It is the original 99 crank. SO I guess it is due to be replaced. Where do you recommend getting a crank from? TIA MIKE Quote Link to comment Share on other sites More sharing options...
rebelbanshee2 Posted September 6, 2004 Report Share Posted September 6, 2004 have you checked the parking brake kill switch??? its sounds EXACTLY like the parking btrake kill switch acting up Quote Link to comment Share on other sites More sharing options...
Jnatali420 Posted September 6, 2004 Report Share Posted September 6, 2004 i had a simialr problem like this one......it would run lean on the right side.....and when i switched the wires it would do the same thing your bike is doing......after about a month.....my machanic did soem tests and after all the time it was just my spark plug caps.....they wernt up to specs.....i spend 10 bucks bought new ones and shee ran like a champ...... Quote Link to comment Share on other sites More sharing options...
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