38mm airstriker keihin carb on a 02 cr125

im just about ready to purchase this carb for my bike, but before i do i was wondering since its bigger than the stock carby if it bolts right up or would i have to change the air manifold and air boot as well? and also if any one is running one on their cr125 now, how do you like it? Any info would be great, thanks!:thumbsup:

I have no experience with this bike and don't even know how big the stock carb is, but I have put bigger carbs on a couple bikes before and have had luck boiling water and soaking the manifold for a bit to get it to fit over the bigger carb. Maybe give that a try?

Thanks 02WR426Cali ill keep that in mind...the stock carb is a 36mm.

Why are you considering this swap? What are you hoping to gain? I have heard of the swap to a CR250 but not the 125.

i'd go with the 36mm personally. i can't really see any benefit to going with the 38 unless you're running WOT all the time. you're definitely going to give up some off idle crispness with the larger carb in a small bore.

it should bolt up no issues, btw.

yah hoping to gain some & i also heard its alot easier to dial in the jetting than the stock. ive read up on a few guys doing the switch and they love it... what im hearing frm alot of people is that this motor is air deprived frm the factory. So intake mods are a must... thats why im tryna find out if anyone knows frm experiance.

schrode thats what i dont want cause the cr125 has no bottom to begin with. but i was talking with jd jetting and they recommended the 38mm??

schrode thats what i dont want cause the cr125 has no bottom to begin with. but i was talking with jd jetting and they recommended the 38mm??

are they recommending the 38 because of ease of jetting or because it will yield the performance improvement that you wants. have you talked to anyone about modding your current carb?

i hear these guys do amazing things.


The 125 is a quandary,and that's why JD recommends a 38mm....they don't make enough power down low, so you have to ride them high in the revs just to get them moving. That said, a CR125 don't really like a 36mm carb, but rather a 38-39mm will really wake them up in the high revs, which is the only place the throttle can be to get the bike moving.

When I had an '06 125sx and an '03 125sx, they both came stock w/ a 39mm PWK air striker carb. Back then, the '06 125sx was the most powerful 125 out there...they were puttlng out about 36 hp, STOCK.

Eric Gorr recommends putting a 38mm tmx on the cr125's from the 06 and up yz125's. I asked him if I could use a PWK instead and he said I could. The difference between the smaller and bigger carbs is, the smaller carb will get more velocity in your air flow at lower rpm's so it gives you a better throttle response at low rpm. The larger carbs flow more air but have less velocity....more air means more power, you get more power from a larger carb but at the expense of some low end throttle response. I have a 38mm pwk in my future plans with my 125 that now has an EG 144 bb kit on it.

Thanks for the info & feed back guys, i think ill give it a try with the 38mm & see how that works out. & like jedd said gotta ride it in high revs. Ill post the results as soon as i get everything installed.

i think i saw somewhere that you can basicly dremel out the exit side of the carb for an extra mm or two. Why not?

I'm pretty sure boring a carb has to be done precise and is a job left to a proffessional

thats for sure cali!! i think i found my final set up a EG133 bore kit, 38mm pwk w/RB designs carb plate, 05 cr125 air boot, vforce3 reeds, mx bonz air boot sealer kit . what u guys think about that set up. i already have a boycen exhaust flange, FMF pipe & silencer.

Don't waste your money on a 133 bore kit. For the price of new piston, rings, cyl boring, You won't even feel a 7cc difference.

Just buy the PWK. THat's the biggest bang on your list.

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