i am having difficulties jetting my blaster with all the mods u see below in my signature, and i am beginning to question the advice that i have been getting from vito's. When i first started up the 240 kit i had in my round slide mikuni 28mm carb a 5f21 needle and the thing would rev out pretty well except that if i accelerated really fast like dragging or something it would bog down as soon as persay i switched from first to second and nailed the gas bag down, it would hesitate, and then it would be fine until i got to the top end and it would not rev out all the way and i mean i tried going all the way up to a 390 main jet and couldn;t get it to rev out strong. So i took vito's advice (they said that this 5f21 was probably frying my engine in the midrange) and i bought their red banshee needle which they suggested. Ever since i installed that needle this thing has been falling on its face immediately...it will idle but as soon as i try to rev it up it sounds like it is drowning or gurgling (best way i can describe it). Should i go back to the old 5f21 needle because at least it ran that way or should i stick with this one and if i stick with tis one wat do i need to do?? i have put the red needle all the way in the leanest position and it starts to get better but i dunno...Any other blaster 240 kits with 28 mm mikuni that can tell me their jetting?? i hope thats enough info, here are my two carb setups with both needles and the main jets i have tried and the needle positions i have tried..thanks
#1 -----> 60 pilot jet, from 340 to 390 main jets and 5f21 needle in the 3 spot (middle)
#2 -----> 60 pilot jet, from 220 to 250 main jets and red banshee needle in all 6 spots


oh and i have done a compression check and that came out at 130 which means its ok

 

It sounds as if you are running pretty rich but the way you describe things I'm scetchy. Bogging and spuutering with little acceleration means your rich and if after the motor gets hot and it's starts really hesitating/backfiring/cutting out then it's lean. Do a spark plug check, that will tell you a lot. black and you're way rich and need to cut down, whitish and lacking color and you're lean. As for the new needle and the new needle and drowning out when you hit the throttle- it's way to big and is not letting any fuel out of the main jet as the throttle slide is being retracted upwards. The pilot jet controls the idle mostly, then the slide rises upwards it controls the amount of gas being let out of the main jet and when you're at full throttle the needle is almost all the way out of the main jet therefore most fuel comes from the main jet.
From the jettin specs you've listed that you've tried, you're extremes and minums are so much that you may be jumping from way to rich with the 340 -90 main, to way to lean with the 220-250. You're main jet will need to be bigger than a 250 definately and smaller than a 340, buy jets in incriments of 10 from 250 to 340. next buy a smaller sizez mikuni needle. possibly 2 needles and 2 sizes smaller. It's just you're jettin bub, you need to experiment. Did you go from stock bore to a 240 without changing you're carbs jets? I can help you with any questions just get back with me.

 

the 5f21 needle is what i initially had in my blaster both before i installed the 240 kit and after i installed it...only after i installed it i bumped my main jet up to a 340 from their. Then i called vito's and they said that the 5f21 needle will be frying my engine in the midrange and they said that i should use their red banshee needle (which is shorter in length and thinner in width than the 5f21). As soon as i put the red banshee needle in i switched my main jet from a 340 to a 240 because that was what vito's recommended. And after the 240 i tried 230 and 220 with the same results, my blaster would just fall on its face, i could not get any good power out of it, i mean all i can say is that it just feels like it is running tooo rich, like the engine is being drowned in too much gasoline and cannot burn it all off. I guess i am just questioning whether or not it is this red banshee needle because it started running like complete crap as soon as i installed it and it seems like i cannot make it lean enough. I mean before when i had the 5f21 needle the blaster would at least rev out almost all the way and it was rideable and made some power...is it the needle??? i don't know what to do... i'm thinking maybe i should try needles that are between the red banshee needle and the 5f21 needle in size...i don't know what to do...another thing, i questioned the pilot jet because when i brought that down to a 45 it seemed to clear up a little bit...i dunno i need help but not from the dealer, they want 250$ to jet this...screw them

 

yeah, screw the 250 dollars man.
When you put the banshee needle in, why did you jump down on the main jet 100 sizes? you're way to lean now with a 240. hell I don't even have a 240 kit and I run a 48 pilot, and the equivalent to a 290 main for a mukuni carb ( i have a kehin)
yeah the reason your blaster is falling out w/ no power is b/c your main jet is way to small and not allowing ANY fuel to pass out of it because the needle is way to big in proportion to it. Keep the banshee needle in your carb and go back to about a 340 main jet. in your tests your posted, you are using way to lean of a main in one and way to rich of a main in the other. Try using the banshee needle and about a 330 main and see if it gets better.
You are using a mikuni correct?
lemme know
James