Welcome to USA-OKO.  We are an authorized US distributor for the OKO factory in Taiwan.  All of our carburetors and carburetor parts come directly from the OKO plant.  On this site and our sister site Mid-AtlanticTrials, you will find carburetors and carburetor kits we have developed after testing the K-Series, D Slides on the various models listed.  As we fit the OKO K-Series to more bikes,  this list will continue to grow.   These "D" slide carburetors are performance carburetors and produce more usable power and better throttle response across the the full throttle range than  round slide carburetors.  All carburetors, kits and accessories listed below are in stock and will usually be shipped within 24 hours of placing an order.  All carburetors and parts are shipped from our facility in New Windsor, Maryland.  If you live nearby you can drop off your bike and we will fit and dial in your OKO free of charge.  We are especially looking to fit the OKO to bikes not on our list. We offer a 30 day warranty on all of our carburetors.  If there is any defect in the carburetor, simply return it to us and we will either repair or replace it, at our discretion, and return it to you at no charge.  If you have any questions, you can e-mail us at:,  or text us at 443-789-2368.  If you want to talk to a real person you can call Roger at 410-635-6722.

We currently carry, in stock, the K series of OKO carburetors in these sizes:
19mm (used primarily for engines under 100cc)
21mm (used for many 100 to 125cc trials and trail bikes),
24mm (used for many 175 to 200cc trials and trail bikes),
26mm (used for many 250 to 300cc trials and trail bikes),
28mm (used for many 325 and larger trials, trail and road bikes)
30mm (used for many 325cc and larger trail and road bikes for those wanting more top end)
32mm (used for many 250cc scrambles/crosscountry bikes)
34mm (used for many 350cc scrambles/cross country bikes and 250cc motocross bikes)
36mm (used for many 400cc and larger scrambles/cross country bikes and 350cc motocross bikes)
38mm (used for many 350cc and larger motocross bikes)
K-101 Standard

K-102  Clear Bowl
K-103  Angled Top
Angled Top & Clear Bowl
Note: All of our Carburetors come in the original packaging from the OKO factory in Taiwan.  There are many Chinese copies available, especially on Ebay.  These often have unmarked jets, are missing pilot holes and/or do not have jet blocks with the correct orifices.  Some are impossible to tune and often parts are not interchangeable with genuine OKOs  If they are being sold without showing the Taiwan flag on the box they are copies.
Click on the small photos for the large size photo.