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Posted

I just got this 87 banshee, upgraded from a blaster, it runs good but it has a jet kit and i dont like using those, im wondering what main jet and what pilot jet and were my clip on the needle should be set at for my mods, ive got fmf pipes with toomey silencers, k'n filters clamped right on the carbs, and i believe thats its, no airleaks and my compression is about 115 in both cylinders at 250 ASL

Posted

jetting is a trial and error prosses start rich 330 with yor jet kit that you dont like but will end up getting to know well. 27.5 pilot. work your way done when you put your 330 in run it some place you can get through the gears 330 will be way rich. more than likley you will not hit the pwerband with this in through 4th gear. keeping dropping main jets till you can hit the power band through every gear im going to say you will end up at 270 or 280 better to start rich. it is a time consuming prosses but it will make you happy in the end and make your motor last for a longer duration if you take the time to do it. are your needles stock? if so id say 4th notch up maybe even 5th hard to say it controls tour mid range. dont try to cahnge everything at tne same time. do your pilot first air fuel screw should be between 1 and 2 turns out. more than 2 increase your pilot less decease. then get mains shot in i prefer doing my needles last. f you try to change eveything at once youll give your self a head ache. good luck

Posted

i checked my mains and there both 280 mikuni main jets, my pilots are 25 mikuni's, luckily the guy must have known how to jet, both sound about right, should i bump the pilots still? how do i adjust the idle and airscrews on these? i know its easy on ablaster but how do i do it on 2 carbs? do i just let it idle then adjust one then do the other while running? 

Posted

i checked my mains and there both 280 mikuni main jets, my pilots are 25 mikuni's, luckily the guy must have known how to jet, both sound about right, should i bump the pilots still? how do i adjust the idle and airscrews on these? i know its easy on ablaster but how do i do it on 2 carbs? do i just let it idle then adjust one then do the other while running? 

 

Carburetor sync is critical on multi cylinder/carb engines. Did you sync carbs properly after reassembling them? This can drastically effect performance and longevity of your engine. Honestly the best way To sync them and set idle would be to have one of the carb sync tools wich measure vacuum thru the carb like this http://www.farmandsandtoys.com/partdetail.asp?partid=59 and make sure each carb shows exactly the same vacuum pressure at idle and adjust each idle screw accordingly to match.  Then use the same tool to make sure they also match at a higher RPM so you can be sure that both slides are moving in sync. If they are not in sync at higher RPM then you would use the cable adjuster on the carb caps to adjust them properly. you can search youtube for a walkthru of this procedure.

 

As for pilot size and A/F screw adjustments, typically if your A/F screws are 1/2 turn out or less for a crisp off idle throttle response then you need a larger pilot. If they are more then 2 turns out for a crisp off idle response then you would go a size lower. those pipes and filter mods like at least a 27.5. personally i run 30s in a similar bike with good results.

  • Like 1
Posted

Carburetor sync is critical on multi cylinder/carb engines. Did you sync carbs properly after reassembling them? This can drastically effect performance and longevity of your engine. Honestly the best way To sync them and set idle would be to have one of the carb sync tools wich measure vacuum thru the carb like this http://www.farmandsandtoys.com/partdetail.asp?partid=59 and make sure each carb shows exactly the same vacuum pressure at idle and adjust each idle screw accordingly to match.  Then use the same tool to make sure they also match at a higher RPM so you can be sure that both slides are moving in sync. If they are not in sync at higher RPM then you would use the cable adjuster on the carb caps to adjust them properly. you can search youtube for a walkthru of this procedure.

 

As for pilot size and A/F screw adjustments, typically if your A/F screws are 1/2 turn out or less for a crisp off idle throttle response then you need a larger pilot. If they are more then 2 turns out for a crisp off idle response then you would go a size lower. those pipes and filter mods like at least a 27.5. personally i run 30s in a similar bike with good results.

i will order some 27.5's does a 280 sound about right for the time being? i did the sync by eye, i watched a video on how to do it without the tool, how do i adjust idle on this thing though?

Posted

280 should be pretty damn close i would think. I cant imagine you need more then a 290. You can only rough it in by eye. get a sync tool and you can sync your idle and your slides. Change idle by each of the screws on the side, Or if you have TORS adjust it on top of that dumbass looking doo hicky on top. Slides you can get pretty close by eye and sound of the slides but idle your going more by sound and feel, and maybe your pipe temps and smoke output. Get a sync tool it takes the guesswork out. Only like 40 bucks from a site sponsor like FAST or even on amazon.

Posted

Do not put a 330 main in your carbs that is way to big for your setup! You should be right around 280 to 290. I agree with starting big and fine tuning but 330 is way to big. 

Posted

Do not put a 330 main in your carbs that is way to big for your setup! You should be right around 280 to 290. I agree with starting big and fine tuning but 330 is way to big. 

work well if it was -30

Posted

thanks guys yeah ill get a sync tool from the site sponsor when payday comes, after i get the bigger pilot jets in ill do a run up the street and piss off the neighbors and then pull my plug to see what it looks like, i eventually want a cfm box but for now these pods will do, and i have my needle on the 4th notch up so hopefully that works well 

Posted

FMF recommmends this for their pipes, this would be with stock airbox. at 1500 asl with 32:1 mix. (quoting their site) i have banshee with fmfs and run with the lid off +4 timing 800ft asl and i use a 30 pilot 300 mains 3rd clip position. its what my motor likes. 

 

  • Main Jet
  • 260
  • Pilot Jet
  • 30
  • Needle
  • STOCK
  • Needle Position
  • 3RD
  • Power Jet
  • N/A
  • Air Screw
  • 1.5
  • Fuel Screw
  • N/A
Posted

Where are you located at?

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