Jetting for cold!

[wobbleknobble]

Today I rejetted my Banshee with a 27.5 pilot air screws out 1.5 and a 260 main, she hauls and no hesitation but smokes like crazy. I also removed my snorkle due to running a tad rich" cutting out on top end, removal of snorkle made it about right. I still don't understand how some guys run those big mains with the same mods I have. My location and sea level I know affects some but a 260-280 is all I can go without cutting out on top end, I run 240-260 in summer with my 25 pilot. Mods are fmf fatty's, k+n, snorkle removed, tors gone with idle screws tapped in. 50:1 Belray H1R. Plug chop show ok, after running all day nice and tan on plugs.

[miner]

good luck. when i got my shee i got t-6's and started with the jets that came with the bike. 220 ran ok so i stuck the 240's in and it tottally ran like shit. stuck the 220's back in and took the snorkle off.this setup ran good but the top end was kinda short. then i found bhq and saw all these huge jet #'s and thought im pretty lucky i dint blow my shit up. now i have 280's and ireally notice how much longer it puls on top but now it runs like shit unless im wide open. iwas going to mess with the needles but my fingers froze to the carb caps :biggrin: f**ck this cold weather ,ill fine tune it in the spring. sorry i didnt have an actual input to help you i was bored :beer:

[dajogejr]

To check your mains properly you need to do a plug chop.

http://www.dfn.com/benkaren/plugchop.html

 

Then...you can adjust the needles, then air screws. Your jetting sounds very, very close to me...

 

You figure if your bike ran great at normal riding temps, say 70 to 90 degrees, you'll go up one size or so on the main for every 15 to 25 degree drop in temp. That's a general rule of thumb.

 

Round here, you normally go up 2 to 3 main sizes when the snow files and the waters freeze.

[Banchetta]

You said you know that temp and elevation changes jetting, but you never said either one!!!!We need some numbers to help you out...for one, your air box lid is holding you back a lot. (4hp) Either remove it or cut the last 1.5" off the end of the over right behind the clips so you still have all 4 clips. I use a skill saw, takes 2 seconds, just don't cut your fingers off...You said you checked your plugs at the end of a day...Your checking your plugs wrong. Run it wide open for 5-10 seconds in 6th gear, pull the clutch in, kill it, coast to a stop, then check the plugs. Tan is lean, chocalate is perfect, black is rich. I'd mix your oil at 32:1. It'll be easier to read your plugs..You also might want to move the needle to the 4th clip and see how it pulls. It'll either pull harder or fall on its face. Let me know how you make out.

[wobbleknobble]

Today I rode my Shee for a few and she run real good. I am still running the 260 mains and 27.5 pilot since the 280 main caused a major bog on top end. The temp has been averaging about 20-30 of a day and 0-5 at night. I am at 961 ft above sea level and have run 50:1 Belray in my bikes for years with no problems. This is my second Banshee and I never had any major jetting issues with the other bike but I was only running Bill's pipe's with a 240 main. On the Cr's I always bumped up one on the main in the winter and was fine. This bike seems to run great with the setup I have now I was just concerned about the others with same setup running such big mains. I do know how to do the plug chop and the ring shows me to be a little rich, but pulls with no hesitation, so I will just ride the wheels of of her. Oh yeah here in the wet mountains running a open or modified air box "besides snorkel or vents" can cause a big gulp of fresh goo to get in I run a outwears with the snorkel off and still get mud drips inside my air box, I don't hit water and mud wide open but the front wheels do a fine job of geting it in there.

[Banchetta]

As long as you run a unmodified lid, you'll never run a large main nor will you even come close to getting the full potential out of the shee. Getting some shit in the box is no big deal, thats why you have a filter....either way, if your happy, that's all that matters.

[wobbleknobble]

Well i have been riding some in the evenings,temps around 20-30. This crazy cold weather drives me crazy with jetting. The other day she run fine with 240's but i felt that it was a little lean do to a faint ring on my plug chop,so I bump up to a 260 this caused a bog on top so I pulled the snorkle off and she was back right with gobs of power. I rode with this setup for a few days and the temps got even colder so I bump to a 280 and the bike still screams and shows to be close on plug chop but still a little lean. These are big jumps on the mains just for 30deg temp changes. Last week I put in the 27.5 pilot and it did make a difference for the best. I rode all evening and just out of curouistity I pulled my plugs while out in the woods they looked nice and dark, so I rode really hard back keeping the revs up in every gear, stopped and pulled plugs again they changed to a tan color. Maybe I need to get some 300's and 310' for this cool weather. The bike runs flawlessly no bogs or anything,how can the bike keep running so good in each range with changing the mains that my jumps?? I am just picky about being right on my tuning, I love the responses for it helps me make decisions on how to propely tune my bike.

[Banchetta]

Well i have been riding some in the evenings,temps around 20-30. This crazy cold weather drives me crazy with jetting. The other day she run fine with 240's but i felt that it was a little lean do to a faint ring on my plug chop,so I bump up to a 260 this caused a bog on top so I pulled the snorkle off and she was back right with gobs of power. I rode with this setup for a few days and the temps got even colder so I bump to a 280 and the bike still screams and shows to be close on plug chop but still a little lean. These are big jumps on the mains just for 30deg temp changes. Last week I put in the 27.5 pilot and it did make a difference for the best. I rode all evening and just out of curouistity I pulled my plugs while out in the woods they looked nice and dark, so I rode really hard back keeping the revs up in every gear, stopped and pulled plugs again they changed to a tan color. Maybe I need to get some 300's and 310' for this cool weather. The bike runs flawlessly no bogs or anything,how can the bike keep running so good in each range with changing the mains that my jumps?? I am just picky about being right on my tuning, I love the responses for it helps me make decisions on how to propely tune my bike.

Your shee is being held back more than you think w/ the lid....Your jetting will change one size for every 15 degrees of air temp....at least now you know that more fuel will make it pull harder. Leaner is NOT meaner....come summer time you'll be able to still run higher mains w/ a modified lid and have a lot more hp....Its a BANSHEE, let her go!!!!