whats size jet to use

[vakidd]

hey guys! I need some help trying to figure out what jet size i need for the set up i have..

engine:
-255cc 40 horsepower 3 mil stroker

-vito's 240 big bore
-vito's 72mm super stock piston kit (made by wiseco)
-tusk high performance HD clutch kit
-cfm performance custom aluminum air box (allows 50% more air flow)
-K&N air filter
-FMF powercore 2 exhaust with FMF fatty pipe
-NGK spark plug
-Mikuni 26 mm carburetor (stock)

i bought the motor through ebay. i replaced the clutch and piston, bearings, etc.. the guy i bought the motor from sent me a hand full of vito's jets. with my setup living in northern virginia (i was told elevation is key) what size jet should i use?

 

[gb blaster]

That's ALOT of motor for the stock mikuni to Handel. May want a bigger carb in the real near future.

 

[vakidd]

What do you suggest?

 

[Blaaster]

A stiff one to call.

Need more information, pre mix or injection, what oil/gas ratio, elevation, temperature, humidity.

Could need any main from between #290 - #320.

Pop in a #320 and plug chop.

 

[Herpderplol]

Throw away the jets you got with it.

Buy genuine mikuni jets, otherwise what we tell you will be off.

 

[gb blaster]

What do you suggest?

I mean it's your call honestly. I'd look into a PWK or a pj if it was my bike Something like a 34.I mean u can run stock as long as its properly jetted. I'm just saying I would go bigger. I'd at least step up to the 28 or a oko 30.

I mean to each his own. Just make sure u plug chop so ur bike runs good.

 

[Blaaster]

The stock carby will perform pretty well with a Fatty as the pipe is designed for low/mid output.

It all depends what kind of performance you want, you want more up top, then a bigger carb will be a good choice.

Properly jetted the stock carb could surprise you.

 

[vakidd]

what do you mean by "plug chop"

 

[Awk08]

these are all stickys at the top of this section you posted in.


tune your carb, in this order........

your engine must be proven airleak free before any jetting can be done:
http://www.blasterforum.com/do-yourself-20/build-use-leakdown-tester-10663/

clean the carb:
http://www.blasterforum.com/carburetor-138/how-clean-your-carb-pics-209/

check/adjust your float height:
http://www.blasterforum.com/carburetor-138/float-heights-how-adjust-them-50565/

adjust airscrew/pilot jet:
http://www.blasterforum.com/carburetor-138/adjusting-your-airscrew-pilot-jet-51060/

adjust needle clip down until it bogs/falls on it's face between 1/4 and 3/4 throttle, then back up 1
(you can also do 1/2 throttle plug chops)

plug chop for main jetting:
http://www.blasterforum.com/carburetor-138/how-plug-chop-53237/