pondtunes Posted February 27, 2010 Report Posted February 27, 2010 (edited) Had a topic on the repair forum but it seems to be now a fuel/carb issue.. The original thread is here: http://bansheehq.com/forums/index.php?showtopic=127045 The short version is the shee idles fine and free revs, however when its under load it bogs and backfires. Carbs are completely clean, air cleaner & crossover tube are in place. 200 main jets, 25 pilots, air screw set at 2.5 turns out. Plugs are black and wet, noticable amount of gas / oil in the exhaust Elevation: 791 FT temps are colder than usual right now, 40's during the day. our spring/summers stay in the 80-100 degree range Edited February 27, 2010 by pondtunes Quote
harbinger of death Posted February 27, 2010 Report Posted February 27, 2010 Had a topic on the repair forum but it seems to be now a fuel/carb issue.. The original thread is here: http://bansheehq.com/forums/index.php?showtopic=127045 The short version is the shee idles fine and free revs, however when its under load it bogs and backfires. Carbs are completely clean, air cleaner & crossover tube are in place. 200 main jets, 25 pilots, air screw set at 2.5 turns out. Plugs are black and wet, noticable amount of gas / oil in the exhaust Elevation: 791 FT temps are colder than usual right now, 40's during the day. our spring/summers stay in the 80-100 degree range Have you checked your reeds? Looks like there has been alot of trash that went through your carbs and why are the threads on your plugs so oily looking in the pics? what are you mixing at? When I ran with no airbox lid at 70 degrees I ran 240 mains. In your first pic there was no crossover tube between the carbs either. Quote
pondtunes Posted February 27, 2010 Author Report Posted February 27, 2010 (edited) Have you checked your reeds? Looks like there has been alot of trash that went through your carbs and why are the threads on your plugs so oily looking in the pics? what are you mixing at? When I ran with no airbox lid at 70 degrees I ran 240 mains. In your first pic there was no crossover tube between the carbs either. No i haven't really messed with the reed valves :\ There's a crossover pipe installed now as the ports on the intake were just plugged. I mixed this batch at 30:1 ratio... From what I think I've gathered here a 240 main would let more fuel in correct? Making it richer.. Logically i would go down (after i check my reeds hehe) On the plus side I can tear this thing down and re-assemble it in my sleep! Edited February 27, 2010 by pondtunes Quote
harbinger of death Posted February 27, 2010 Report Posted February 27, 2010 No i haven't really messed with the reed valves :\ There's a crossover pipe installed now as the ports on the intake were just plugged. I mixed this batch at 30:1 ratio... From what I think I've gathered here a 240 main would let more fuel in correct? Making it richer.. Logically i would go down (after i check my reeds hehe) On the plus side I can tear this thing down and re-assemble it in my sleep! Do you shut the fuel off when not riding? I've seen raw fuel coming out of the pipes when kicked over because the needles and seats were shot. You may have fuel running into the crankcase causing your rich condition. Also if your reeds are shot it might be part of your backfire problem. And PLEASE clean that thing up! 64 degrees is not cold! Quote
pondtunes Posted February 27, 2010 Author Report Posted February 27, 2010 (edited) Okay just tore this thing back down to the reeds.. (photos here) -> http://bansheehq.com/forums/index.php?showtopic=127045&view=findpost&p=1100741 the reeds *look* okay to me as far as not being broken or having cracks.. The lower ones did have a visually detectable gap between the reed and the reed housing... Both sides seemed to look the same. What's next? and for the most part I do shut the fuel off... how do i tell if the needles/seats are shot and how important is the tiny washer that goes under the main jet in the carb? One seems to be missing... I have a new splash guard ordered and the lady says it comes with the washer. Edited February 27, 2010 by pondtunes Quote
pondtunes Posted February 28, 2010 Author Report Posted February 28, 2010 Okay i took the reed valves apart and cleaned them with carb cleaner and re-assembled. The right side still has a very small gap on the lower side where the left side does not! Should there be a gap at all? Quote
skj283 Posted February 28, 2010 Report Posted February 28, 2010 have u unplugged the tors brain up underneath the tank. if someone just cut the wires and didnt unplug the brain maybe could contribute? Quote
harbinger of death Posted February 28, 2010 Report Posted February 28, 2010 Okay just tore this thing back down to the reeds.. (photos here) -> http://bansheehq.com/forums/index.php?showtopic=127045&view=findpost&p=1100741 the reeds *look* okay to me as far as not being broken or having cracks.. The lower ones did have a visually detectable gap between the reed and the reed housing... Both sides seemed to look the same. What's next? and for the most part I do shut the fuel off... how do i tell if the needles/seats are shot and how important is the tiny washer that goes under the main jet in the carb? One seems to be missing... I have a new splash guard ordered and the lady says it comes with the washer. According to the yamaha service manual the reeds should sit flush or near flush against neoprene seats so if you have a gap they're probably shot. You should get a yamaha or clymers manual, all the specs are in them. Quote
pondtunes Posted February 28, 2010 Author Report Posted February 28, 2010 Okay more updates, After reading up on adjusting the carbs i have determined that since my problem is in the 3/4 or less range perhaps I should adjust the needle / slide.... Upon tearing down the needle/slide assembly i found the E clip was already on the notch closest to the blunt end of the needle.. From what I read this should be the leanest setting... I had really hoped that it was set to the richest setting (closest to the tapered end so that i could lean this circuit out...) moving it down should make the problem worse right? Quote
pondtunes Posted February 28, 2010 Author Report Posted February 28, 2010 (edited) Wheee! What a night! I tore the engine down to the reeds, removed them, taped up the exhaust and intake ports and loaded ole dirty bastard into the back of the truck.. Took it to the car wash and degreased the crap out of it... Who woulda thought the engine was aluminum and not brown dirt! Anyways, took the reeds apart, cleaned them well and re-installed everything. Fired it up and i noticed I only had one side running well... Nice pop pop 2 stroke sound.. The other pipe was dripping oil, i assumed my plug was dead. Swapped plugs and the problem moved. So I bought new plugs. Slapped the new plugs in and took off today and after some adjustments it seems to be much better! I still have a bog at WOT so I assume the only way to fix this is with a jet. I moved the needle to the stock position upon re-assembly it was closest to the blunt end. My idle is a little smoky but it really hits the powerband hard with as much as 3/4 throttle and stays in it. I can definately tell when I pass 3/4 throttle though because its a definite bog! Btw my plugs are still wet and oily but i no longer have oil coming out the exhaust everywhere. Moreso the right carb than the left. Should I try the choke trick to see if it goes on up at WOT now?!? Edited February 28, 2010 by pondtunes Quote
Smokestack Posted February 28, 2010 Report Posted February 28, 2010 I would do a comp test...If its ok richen the main. Quote
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