What carb to get?

[blasterboy32]

I have a blaster with a vito 240 BBK. Its running very lean. I did a leak down test and it turned out fine so im thinking i need a bigger carb. I have the stock one on there right now. I also have a pro circuit pipe, Oil block off and the air box lid off. What carb should i get? I want a good carb but dont have a lot to spend. I also plan on having some porting done in the near future. I want a carb that i will still be able to use after that is done. If you could give me a specific carb that would be a big help but a recomendation on size will work too. Thanks in advance for any reccomendations.

 

[Quadrider10]

I have a blaster with a vito 240 BBK. Its running very lean. I did a leak down test and it turned out fine so im thinking i need a bigger carb. I have the stock one on there right now. I also have a pro circuit pipe, Oil block off and the air box lid off. What carb should i get? I want a good carb but dont have a lot to spend. I also plan on having some porting done in the near future. I want a carb that i will still be able to use after that is done. If you could give me a specific carb that would be a big help but a recomendation on size will work too. Thanks in advance for any reccomendations.

u dont need a new carb if its running lean or rich. u just need to rejet

 

[scotj77]

with a bbk and porting I would go to an oko 30mm or kehin 30mm-35mm. but for now you should be able to rejet to keep it from leanin out. what main jet are you running?

 

[StrokedTater244]

X2 on the pwk carbs, best available IMO. either 33, 35 or 36mm keihin pwk would be what i would run on that. 33mm for better bottom-mid power. 35,36mm for better mid-topend power. anther good carb at a cheaper price would be a kehin pj34mm. they came stock on honda 250r's and are a good upgrade as well.

also i wouldnt keep riding it if it is running lean. probably sooner than later it is going to get too hot and cause damage to your topend. at least jet the stock carb accordingly, as stated already.

 

[sicivicdude]

u dont need a new carb if its running lean or rich. u just need to rejet

with a bbk and porting I would go to an oko 30mm or kehin 30mm-35mm. but for now you should be able to rejet to keep it from leanin out. what main jet are you running?

The reason a stock carburetor isn't recommended on a Big Bore Kit is not because of air to fuel ratio but because of volume of supply. The stock carburetor isn't terrible for a stock bore stock stroke blaster but a BBK is a 20% increase in displacement without a 20% increase in possible flow from the carburetor.

If the stock carburetor isn't running lean it certainly isn't getting the most out of that BBK.

I'd recommend a Keihin PWK 35 -36 or PJ 34 or a Mikuni TM 34-36. Lots of these carburetors are available used as dirtbike carburetors or available aftermarket from suppliers like Sudco or CPW.com

I believe a 28-30 mm carb would be too small. I would SHOOT for a PWK35 (I'm running one on my stroker vito's BBK and it RAWKS!)

 

[blasterboy32]

I'm running a 290 main right now. I don't really want to buy a new Carb right now but if its going to make it run better ill buy one. Out of all the ones reccpmended which costs less

 

[scotj77]

you should be up in the 310-330 range I would think. that 290 is too small

 

[sicivicdude]

well that depends on where you get it. There are second hand carburetors (PWK35's normally!) on the for sale section every so often for $100 or so.

Brand new, the Mikuni TM series is less expensive.

 

[scotj77]

i picked up my pwk 35mm airstriker for 100 bux here, great shape

 

[blasterboy32]

CARB JET KIT FOR OEM CARBS...

Should i get the first or second product on that page. I guess im going to try to rejet before spending money on a carb. I figured i could by 8 different sizes of the second product for the same price as the first product. So should i go with the individual jets so that i could buy a bunch of different ones to get it right? But the kit says its for a 240BBK with the airbox lid off which is what i have.

 

[scotj77]

get the minuki jets. off brand jets are not very good. you want the hex/main jets. your pilot should be fine. i would get 300-350 if i were you

 

[StrokedTater244]

i would not use a vitos needle, too many bad stories about them. turn the airscrew in 1/2 to a full turn. start at 340 on the main, richen the needle clip postion one notch. that should be plenty rich to start and tune it from there.

 

[blasterboy32]

i would not use a vitos needle, too many bad stories about them. turn the airscrew in 1/2 to a full turn. start at 340 on the main, richen the needle clip postion one notch. that should be plenty rich to start and tune it from there.[/QU

I already have an aftermarket needle. Not sure what it is but not stock. What position should the needle be at? Ill order 310-350. And did i understand correctly to put the air screw the whole way in then twist out 1.5 turns?

 

[scotj77]

what he is saying is turn the air screw in 1/2 to 1 full turn in from the factory setting(1.5 turns out) looks like i might have been a little lean on my suggestions. maybe order 320-370 if tater says start at 340. he knows his stuff.

 

[StrokedTater244]

yeah scott is right on the airscrew. turn it in from where it is now 1/2 turn or so to richen it up a bit. if it still acts lean at idle and 1/8 throttle go up a size on the pilot. i have alway used and suggested stock needles, they work fine. as for the needle clip, put it in the first notch down from the middle. or the 4th notch (on most needles). scott i think you were fine on the sizes you said. im saying start at a 340, because i do not think it will need anything fatter than that. probably have to work down a bit.

im not going to type out a jetting 101 article, sorry, plenty of threads already on here about it.

 

[blasterboy32]

so maybe order 320-360. i dont want to have to pay for shipping twice so i'd rather order extras either up or down than have to place another order.

 

[scotj77]

sounds good that should get ya there

 

[blasterboy32]

Thanks for all the help. I just ordered 320-360. when i try each jet do i need to do a plug chop with each different seize or could i try to decide how it is by just feeling how it runs and what the plug looks like.