What size carb???

[Master_Blaster]

I have seen all different size carbs people have used but my question is how do you know what size carb for what application???

Any advice would be much appreciated...

As for my motor setup(currently building) I'm going to have a +3 stroker crank, V Force 3 Reeds, Dynoport Pipe and some mild porting and possiably shaving the head......please lmk as I am not to knowledgable when it comes to motors...

 

[lassek]

Yeah i wanna know that aswell.. because many people mean diffrent..

Some say it is only nessecary with carb with big bore or super port???

But i cant see why a big carb wont benefit ex. 68mm stock /w Wiseco mild port, complete Toomey B1 , Vf3 , Milled head etc etc.. I mean i would boost more power than stock carb so why not???

 

[blasterfreek30]

yes a bigger carb will help out with a stock motor, i ran a 34mm before i got the port job, and it almost seemed like i gained another gear because of the bigger carb, but it still ran good

 

[lassek]

what is the best size carb for 68mm stock but mild port and clenup port with wiseco 68mm piston and head milled and redesigned, Vf3 reed cage, Tommey complete, airfilter exhaust etc.. ..

34, 35 ? bigger?

 

[blasterfreek30]

66mm is stock size, with those mods i would try a 30mm

 

[Master_Blaster]

So any advice for my motor setup???

 

[blasterfreek30]

sounds like a good setup to me, just remember if u do go with the +3mm crank it has to be ported to match the longer stroke, and with that setup i would try to get ahold of a 35 pwk carb

 

[cwright#26]

Master with your setup a 35pwk airstryker will do you well. Lassek a 33pwk or 34pj would help your cause alot, don't go bigger than a 35 whatever you end up doing.

 

[lassek]

Ok that sounds nice, but why should i only get a 33 or 34 if you recommend 35 for MasterBlaster.. ?

I mean i have a lot of tuning parts to support it? And why is bigger not better in the Blaster world.. i mean 2wheeler mx bikes always have huge carbs.. 35-38mm.. even a 125cc has a freakin 38mm!

Would it be waste to buy a 30 mm ? that fits stock intake boot etc... or is the diffrence so small so its a waste..

 

[lassek]

bump anyone? ..

 

[cwright#26]

The Master has a +3 stroker and you dont. How hot is your porting going to be and who's doing it? You could run the 35 with that setup, but unless your porting is going to be pretty wild you will have some overkill and lose bottom end power. My fault on the late reply

 

[lassek]

cwright#26

I am also considering a stoker +3mm crank, my porting is limited.... im doing it myself.. first of all the exhaust has been made 1mm wider and lifted 1mm .. the transfers are totally cleaned but not modified inside the bore, the intake has been very nice ported but no worm holes.. Along with that is the complete Toomey B1 kit.. VF3 reedcage, milled head .035" and redesigned the squishangle..

I dont wanna kiss my low and midrange goodbye for high topend.. i guess i could go with 30-34mm ?

But if I only change the carb to a 30mm ... and re-use all stock boots.. will i even notice it? I mean its only 4mm carb extra..

 

[FLOTEK]

there is no universal ansewer .this is why its best to have a builder who is familiar with setting these mods up to work in unison for best results.. alot of things must be considered like what kind of state of tune/porting layout .. what fue l, what kind of riding/power delivery is the bike being used for.it is much more than displacment alone ..often i see alot of guys think becuase a 250 dirtbike uses a 38mm+ carb that they should too for best power gains,problem is alot of these modern bikes have way different ultra high tech port and head designs made for three qaurter -full throttle runs on a closed coarse track and can rev to 11,000 rpms also they use advanced power valve assemblies to aid in this and have drasticly less rotational mass and need for strong low end torque required to lug a 350 pound machine around muddy trails.too small it will choke out after half throttle due to lack of CFM flow ....too large and it will reduce intake velocity and make poor lowend torque/response

 

[lassek]

FLOTEK: I totally agree.. BEFORE i thougt the bigger the better regarding carb.. but you are right.. my buddy´s Husky 250r has a 38mm .. but the reed valve in the engine is also 50% larger than the blaster! :-o . . So a lot parameters count..

I may just go for the biggest carb that can fit stock boots.. is that a 30mm ?

But will the diff between 26 and 30 be noticeable ?

Lasse

 

[2smoker85]

Master with your setup a 35pwk airstryker will do you well. Lassek a 33pwk or 34pj would help your cause alot, don't go bigger than a 35 whatever you end up doing.

you can't be serious? with my mods i am running 34mm, its perfect, about to throw the 240 on mine, unless you do major porting or bb kit, don't go over 34mm, and master you would be good with a
30mm. otherwise you are going to lose lowend torque and response. you can ask the builders on here that do your work what to run in conjunction with what you have that would be ur best bet