250r jetting with a 38mm carb

[85 250sx]

well i just got a 38.5mm Kiehn carb and i was looking for a ballpark figure as to where i should start with jetting its a 86 250r it has a K&N air filter with the air box lid off Delta v-force 3 reeds and a pual turner hi rev. pipe. the cylinder is stock no port n polish or raised compression (not yet anyways:naughty: )

im sure someones running somthing close to this set up and could give me some pointers the main jet in the carb right now is a 175
hopefully its somewhere close since i wana go riding tomarrow and no cycle shops are open on sundays.
thanks for anyhelp

[Pete]

I'd probably start out at about 165 main, middle needle clip, and a 52 pilot.

[GPracer2500]

I'm at 1300ft, mid-60s temps. My 85 has a 38PJ carb, PT High Rev w/ Fat Boy silencer, foam filter with vented lid, Boysen dual stage reeds in stock cage, porting of unknown orgin/style, 180psi compression.

I'm at a 172 main, DGK needle on 3rd clip position, 58 pilot, 1 1/2 turns out on the air screw. Not sure if I'm dead-on, but it runs clean throughout the rpm range.

[BNRturbos.com]

I have a 52 pilot and a 182 main jet with a 38.5mm carb. My bike has a stroker kit and is ported a bit. It has a FMF pipes upgraded reed cage, with filter.

[oldsking86]

Not trying to go off topic here, but I also have a 86 250R, has an aftermarket pipe and FMF silencer, no motor work ( all stock compression) with just a vented airbox ( with the foam filter).. What size carb would you honda guys recommend using, 38mm? If I di this I take it I would have to put some bosen reeds too?

[Pete]

if you plan on leaving the engine stock, with pump gas etc I would use a 35mm Keihin PWK or a 36mm Keihin PJ. The Mikuni TMX is a nice carb in those sizes as well.

[gravelord]

38mm is GREAT for top end with a stock bore cylinder, oldsking, when i had a stock cylinder and stock head, and i put on a 38mm air stryker carb.... it was AWESOME, it woke it up ALOT..... you will love your self for putting it on, i ran on pump gas too. you dont have to worry about switching over to higher octane unless your head is milled or your ported, or running a big bore.
youll be fine on pump gas. all two strokes like higher octane though

[oldsking86]

Thanks guys, yea I was in debates on bigger, didn't know by how much because I didn't want overkill either lol I'm definetly looking into a 38mm or even a 36mm, which ever I can grab cheaper haha