question on jetting for a big bore 310

[LT250Racer609]

ok...where should i start with the jetting with a 38 MM carb. and a 310 kit? what size main jet, where the needle should be...etc. i just need somewhere to start then i can break it in from there

[zedicus00]

we need more info, everything form pipe on quad to elevation u r rideing at, and aproximate climate.... me helping u jet is gunna depend on u helping me figure out yur situation.

[BLACKeR]

they manufacturer you bought it from should be able to give you a starting point. jetting is always a guessing game initially, call the guys you bought it from they should be able to hook you up.

[LT250Racer609]

well it isnt mine is a buddies and im trying to help him out...

anyways in located in NY and the temp. is normally between mid 70's to high 80's

i know he will be running a curtis sparks MX pipe with a curtis sparks silencer and he has a Vforce reed valve

[zedicus00]

my jets are a 57 pilot and 210 main on a big bore midrange setup in KS... go from there i guess? if it blows up i didnt do it.

[1988R]

Originally posted by zedicus00
my jets are a 57 pilot and 210 main on a big bore midrange setup in KS... go from there i guess? if it blows up i didnt do it.

What size big bore are you running? I use a 38mm with 45 pilot and 180 main. Im in PA right about at sea level. and its been 80's low 90's you have me worried Im running lean

[1988R]

Originally posted by BLACKeR
they manufacturer you bought it from should be able to give you a starting point. jetting is always a guessing game initially, call the guys you bought it from they should be able to hook you up.

Not always the case. my buddy bought a Curtis Sparks for his YFZ this past winter and was having a hell of a time getting the jetting right. When he called Curtis Sparks they told him "it doesnt get that cold where we are at" And that was all the info they gave him

[machwon]

If it is a Keihin carb I would start at the following:

DGH needle middle notch
42-48 pilot
178-185 main

[hang1p]

im running a 60 pilot 1 turn out 4 notch fro the bottom on needle
and a 180 main in the 80 degree weather about 0 elevation with a trx 5 center mount pipe no air box on a 330 with a 39mm pj carb

[zedicus00]

my bore is a like 304 i belive sleeved stock cylinder (on last bore) 38mm A/S short body carb. huge aluminum ported intake manifold with custom ported v-force 3 reeds, ESR TRX-5 standard mount.

mine sux a LOT of air and fuel through it cuz of all the port work done to the jug and the intake, and its actually textured intake tract not a smooth polished one.

anyways, 57 pilot 210 main at 3000 feet elevation in 80 degree average whaether on mixed 110 oct with pumpgass at half&half. running 200Psi, 50:1 golden spectro, 14:36 gears and i weigh 200lbs. oh middle clip on needle an i didnt count air screw turns i just set it by listening to the engine. should b between 1.5 and 3 or u need to change a jet.

BR5 iridium plug.

runs like a RAPED APE!