Welcome to USA-OKO.  We are an authorized US distributor for the OKO factory in Taiwan, located in New Windsor, Maryland.  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 carburetor kits we have developed after testing the K-Series, D Slides on the various models listed.   If you need a carburetor for a bike we do not have a kit for, we will work with you to get the carburetor dialed properly, exchanging jets, and even the carburetor size if needed.   You have the option to buy just the basic carburetor, or a deluxe version with extra jets and needles to assist you at dialing it in.  We also carry a complete line of spare parts, as well as accessories.   All of our OKO carburetors come with a 30 day guarantee.  If there is any defect in the carburetor, simply return it to us.  We will either repair or replace it and send it back to you, at no charge.  If you have any questions regarding application, tuning, or problems, 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
Though originally copied from the Keihin PWK series, OKO has continued to test and develop the OKO D slide carburetors, offering sizes not previously available, and refining the internal components.  Some parts are interchangeable with the 28mm Keihin, but many are not.

Many Chines companies are now copying the OKOs and marketing them as genuine.  Though these copies look practically identical, the internal drillings are often not right, making them impossible to tune.  Many are available on Ebay, as well as through organizations marketing Chinese products, such as Alibaba.  The best way to determine a genuine OKO from a copy is by the packaging.  All genuine OKOs come in packages with the Taiwan flag on the box.  The copies coming from China will have a white rectangle where the flag should be, denoting the carburetor size.  Buyers be warned that often genuine parts do not fit the copies, making many of them impossible to fix.
Click on the small photos for the large size photo.
Chinese  Copies Hurting the OKO Reputation
Please Note:  We've been very slow to develop this site.  At this time, Mid-Atlantic Trials, our sister site, has much more information and OKO products available.