Starting Point

[Wheelie Ripper]

I was wondering what a good starting point would be for my banshee. Its bored .040 over, 4mm long rod, cool head 20cc domes, +5 timing, paul turner mid range pipes, k&n filter with air box lid still on. The motor has no port work done and I will be using a spacer plate for the time being until I can get it ported. What would be a good place to start? Thanks in advance for any help.

[AKheathen]

what is your elevation and ridding temps? you do realize that setup still needs at least 50/50 race/pump fuel at sea level, right?

[Wheelie Ripper]

My elevation is about 500', and temps range from 40's-90's. I currently run straight 100LL fuel so that is not big deal. Also I am running stock carbs.

[TwistedSheeRida]

Next i would get some bigger carbs 33mm or 35mm with some uni pods. i wouldnt jump to conclusions and say you NEED to run higher octane gas. i know a guy running a long rod crank, full drag port, stock cyl, cool head with 18cc domes @ sea level, 38 pwks, 87 oct pump gas. Is it running on the edge? Yes but it has been for 3 years with zero problems.

[Wheelie Ripper]

eventually i will upgrade my carbs, but for the time being, i need to work with what i have. Im thinking starting out at 380's and then plug chop it.

[AKheathen]

well, if you noticed, i said "at sea level" and yes, that setup needs more than 93 octane, even at 500'........now, the thing is, that the spacer plate and stock porting is going to lower the eficiencies, and i'm not sure how much that will effect the jetting, so , start with the 380's, needle in the middle, and airscrews at 1.25 turns from seated. get her warmmed up to operating temp and open it up. if you get some sputter or breakup wot, then go down on the mains untill it runs clean wot, and then do a plug chop. once the mains are good, adjust the needles, if needed, for the 1/4-3/4 throttle range, and then the pilots for idle to 1/4. then, re-adjust the airscrews. i would have to guess you'd be around 350-360 at 40 degrees. as for the carbs- it depends on aplication. of you are focusing on topend, then 33-34 wold be good, however, by your pipe choice, you will be much happier with 28-30 for nice bottom end and mid performance without killing the topend either. but, the porting and aplication will be the deciding factor. ...right now, the stockers will be just fine.