EvilBanshee

No i know plenty... 2 into 1 set up's are junk. They make no power on the top end vs a dual set up. These engines need to breath, and single 33mm carb want have near enough CFM as a nice dual set of 26 or 28mm carbs.

Im gunna be the one who disagree's, The rings will seat better after a few hours of running. Like i just said on another post, My 421 gained compression after 3 hours of hard run time. I agreee, Dont baby it, Let it get warm, and run it hard. The rings will seat better under high load.

Have you ever ran "2 into 1?" YOu will need a 39mm carb minimum. YOu should get a set of dual 28mm carbs, it will work alot better. Yes more compression will give you low end,

My 421 jumped up 25psi after a few days of riding. Roughly 3 hours worth of riding. Also make sure you break it in With lots of throttle movement. Lots of WOT!! Push those rings out!!

If i were you, i would run 21CC domes. That gives you lots to play with On 91 octane. If i were you i would crank up your timing 6 degree's with that set up aswell. Im goin off the assumption you are a stock engine? Stock CC, stock port's ect?

LOL iv done that before.... It happens! MY first build with new carbs. The bikes dont run to well when the slides are in backwards..

Is your engine broken in? YOu ll need 4 hours on it for the rings to seat. Makes a big difference

Sounds like your clutch is sticking. CHange you oil with oil that is meant for Wet Clutching. MOTUL or Bel RAY.

Vito's come trued and welded as well. I run the +4 stroker crank. They are built well.

Try new CDI, and NEW plug boots. If that doesnt work. YOur stator puked...

Bel Ray CLutch Saver. even MOTUL Transmission oil.

Could be a leak, could be poor fuel. YOu have plenty of octane for your elevation and compression. How old is the engine? Have you checked your squish?

ALSO a hint. Try new plugs. Once you foul a set of NGK's. They are never right after.... Gap them at .030-.025.

Oh ok, ya 19cc domes on 91octane is the EXXtreme limit. Well all i can say, if your having trouble. JUst be patient with your jetting. Start with pilots. Get it starting easy when stone cold. Then move to your needles and mains. IT will take a long time to get it jetted perfect. But you ll get their. GOOD LUCK MAN!!

Minimum i would use 100LL.

By the looks of it that plug has a few hours on it. YOur color is good, light light tan. I would say your jetting is darn close. Throw a fresh set of plugs in, and do a true WOT test. The ring should be very thin at the base.

Not trying to be rude, but did you drive the banshee before you started messing around with it? YOu did waaay to many changes at once.... 1 thing i have learned with my banshee, snowmobile and drag car. One change at a time. No matter what. Your gunna be chasing you tail now... Why do you think that set up isnt meant for pump fuel? 21cc domes arent that crazy on a stock engine size.

Give it a try, their is lots of power to be unlocked when you start to play with the dome configuration and squish. You can also kill the power as well if you have no clue what your doing lol. I would give it a try first, if its gutless, Throw a different set of domes in it.

At you elevation. I would think 20cc domes safely on 93. Possibly 19cc domes, but thats pushing it on straight 93.

Very true, port timing has a big effect. I didnt know you had him port your cylinders.. I thouight u meant he just re shaped your domes for you, and that was all he did.

Id say the thickness on that plug band is bang on. BUt it looks like your running diesel in that engine. DRop 2 main sizes. YOU want a lighter color ring then that. More of a tan.

usually the higher the elevation, the more compression you can use, and get away with less octane. I would think you could be able to run 20cc domes easily. Custom cut domes controls FLame speed and squish in the cumbustion chamber. YOu ll have to ask him why he went with such a low compression dome.

My 421 has 45 pilot. IF your banshee starts up cold with in 2-3 kicks and runs decent. you pilot is fine.

I had this problem, I bought my Carbs used. AS a set. Turned out, my needles were different sizes. One side ran leaner then the other.

Those plugs are FAT.( RICH) YOu want a light light tan color. NOw when tuning your main jets, put in a new set up plugs (GAPPED at .025-.030 on a semi stock engine). DO 4 or 5 WOT sessions. Run through the gears, hold it pinned the entire time, Once your topped out. Pull the clutch in and shut it down. THen check your plugs. IF i were you id drop your mains 2 sizes. See how it looks. When playing with your needles and pilots. GO fairly big swings. and see if it gets better. If you think u need a bigger pilot, go 5 sizes bigger. Same with the needles, go accouple clip's bigger or smaller. See if it clears up. or gets worse. Its hard to tell if u go 1 setting at a time.