Note:  Carburetors are jetted according to the  settings used in our actual trials.   It must be noted that older bikes are not like new bikes coming off of the assembly line with perfect timing and compression and with unrestricted exhaust systems.  Carburetor tuning is based on all of these factors, which vary greatly on older bikes, even of the exact same model.  Settings will vary some from our test bikes according to the condition of your engine and exhaust system, even your air filter.  To get the most out of your OKO carburetor, make sure your timing is correct, your compression is good, and your exhaust system and air filter are unclogged.  Also, it cannot be stressed enough to use a good quality fuel filter.  Most fuel leaking from carburetors is due to a small piece of dirt or grit lodged in the float needle seat.  If the dirt makes it past the float needle it will often find a home in your pilot or main jet.  On two-stroke engines, use a good quality two-stroke oil at a 50:1 or higher ratio.  We will include extra jets with your kit for differences in elevation and the other above factors.  Use these to fine tune the OKO to your engine.  If you have any questions or problems you can e-mail us at and we will respond, generally within twelve hours or less.  If you prefer to talk to a real person, call me, Roger, at 410-635-6722.  If there is no answer, leave a message or try my cell phone at 443-821-6154.
For those close by we offer free installation and dialing in of your OKO on practically any bike you wish to instal it on.  Just give me a call.
USA-OKO is an authorized distributor for the OKO factory in Taiwan. All carburetors and parts come to us directly from the OKO factory.  Below you will find OKO 'D' Slide carburetors from 19mm to 38mm suited for motorcycle engines from about 50cc and up.  We also carry a full supply of parts, needles and jets and can order any parts you may need if they are not currently in stock.  All orders ship from our location in New Windsor, MD, USA within 24 hours of receipt of payment.  All purchases are made through Paypal.  If you do not have a Paypal account, at check out you have the option to use a credit card instead.  We can also do phone orders for credit cards.  Note:  If you have questions, our email is, shop phone is 410-635-6722 and cell phone is 443-821-6154.  

Click for Information and Photos
Click For Information and Photos
Click for Information  for TY 175 and TY 250
All purchases are made through PayPal. 

If you don't have a Paypal  account you can choose the option to use a credit card at check out.
So, what happens once I place my order?
Once we have your order, we take the correct size carburetor off the shelf.  We disassemble it, check and set the float height and replace jets and the needle as needed for the application.  Then we make sure all internal passages are clear and make sure the float needle seals as it should.  For carburetor kits, we prepare a manifold and/or airbox hose adapter if required.  We then gather extra jets as needed for differences in elevation, airboxes and exhausts.  We also include a shim for the needle as many engines require the needle clip to be set mid-way between the needle notches.  Your order is then boxed and labeled for shipment, either that day, or the following if the order is placed late in the day.  A tuning guide and information sheet for each application is included.  All domestic kits ship via USPS Priority Mail.  Shipping cost is included in the price of the kit.  International orders are shipped via USPS First Class Mail and usually take a week to fourteen days at the most to arrive at the most distant countries.  Please note however, that during the current pandemic, many countries are holding imports for an extended time, making it difficult to determine the actual receipt date of the order.    Note:  All shipments will have a tracking number with USPS.  Contact us if you do not have the tracking number once we ship.
 K-104  Series - 32mm to 40mm

Return Policy Note:  We offer a 90 day warranty on all carburetors.  If the carburetor cannot be dialed in due to a defect in the carburetor, simply return it within 90days of the purchase date and we will repair or replace it, at our discretion, and ship it back to you at no cost.  You only need to pay to ship it to us.  Also, if we have not included the correct jets or needle (kits and "Deluxe Carburetors" only), we will work with you on an exchange basis.  Send us the jets or needle that are not correct and we will send you replacements as per your request, again at no cost to you.  We will work with you as much as possible to get your OKO properly dialed in.  If there are no issues with the carburetor and you have just changed your mind about using it, you can return it within two weeks of receiving it, for a refund.  We do require a restocking fee of $20.00 for sales within the USA, $30.00 for sales to Canada and $40.00 for other international destinations.  This allows us to recoup shipping and Paypal fees.  There is some mechanical ability required for proper installation and set-up.  Please consider this before ordering.   You can call Roger at 410-635-6722 (evenings), or 443-821-6154 (days) with any tuning or other general questions.  We will assist you as much as possible with any issues.

Click for Information and Photos
For those of you who want the best flow possible through your carburetor's bore we now offer all of our K-101 Series Carburetors with a hand polished bore which includes the top of the jet block.  Imperfections in the casting are smoothed to a mirror-like finish assuring the best possible flow.  If you've ported and polished else where you may want to also have your carburetor bore polished as well.  After selecting the carburetor or kit you want, select the Hand Polish option from the button to the right.
Hand Polished Bore
Please Note:  Many Chinese companies are now copying the OKOs and marketing them as genuine.  Externally, they appear the same, but often the internal drillings are not correct, making them impossible to tune.  They are available on Ebay and through companies marketing Chinese products, like Alibaba.  Their prices are good, but function often is not.  Be aware that genuine parts which could fix the copies, often do not fit.  The best way to tell a genuine OKO from a copy is that all genuine OKOs come with the Taiwan flag in the upper righthand corner of the box.  Beyond that, only genuine OKOs have four holes in the body to accept the clear, plastic bowl.  Copies only have two for the metal bowl, and not the extra two.  Copies will have a white rectangle in place of the Taiwan flag, denoting the size of the carburetor.  You can click the button above to find out more about genuine OKOs and the Chinese copies.  
If we don't have a specific kit your your engine, you can put together all that you need here.  Just select the size you want, jetting if you know it, and any extras you may want as well.  We have jetting for many models not listed here.  You can contact us for jetting information, or we will add it to your order if known.  

Select the size you want and the shipping destination.   Tell us the jetting you want if it is known.  
Carburetor Kits For Specific Motorcycles
The Ultimate Performer
21mm-26mm Carburetors
For those of you who want the best performance from the 21mm through 26mm carburetors, we now offer the "Ultimate Performer" modification to increase top end perfomance without loss of any low and mid-range power.  OKOs are already known for their superior performance, and this mod takes them to the next level, providing extra top end power and revving ability.  After selecting the carburetor or kit you want, select the "Ultimate Performer" modification.
Note:  Special thanks to reknowned stuntman and trials rider, Lane Leavitt for help with testing these carburetors.
Ultimate Perform & Polish Options
Add Hand Polishing and/or the Ultimate Performer
to my already selected Carburetor or Kit
 Hand Polishing and Ultimate Performer
Build Your Own Carburetor Kit
Black K-101 Carburetor

Click the Buttons Above for Detailed OKO Information
Select Destination, Including Shipping
Size of Black K-101
Jetting if it is known
Start by selecting the size you need and the shipping destination.  Available only in Metallic.  Tell us the jetting you want if it is known.  Note: 40mms are special order.
Select Destination, Including Shipping
Carburetor Size
Jetting if it is known
Items You May Also Need
OKO offers this clear float bowl for the K-101 series so you can easily check the float level, or see if any dirt or water has accumulated in the bowl.  It attaches with four screws (incuded).  It does not have the bottom nut for access to the main jet.  
Jet Kits
Enter Sizes Wanted if Known
This curved top for the K-101 is  sometimes the answer to limited space above the carburetor.  It uses slightly more free cable than the straight top.
Carburetor Top Options
We offer extra jets kits either richer and/or leaner than those in your carburetor order, or you can select the sizes you want.  These are exchangeable if they are not correct.  Simply ship them back to us and tell us what you need instead and we will ship you those.
Float Bowl Options
Carburetor Size
We have four adapters for manifolds with studs that hold the carburetor in place (photo on left), and four sleeves for carburetors that are spigot mounted.  Check your manifold to see which adapter or sleeve will work for you.
Rubber Manifold Adapters
Adapter Size:
Domino Throttles
This is the Domino slow throttle used in  trials. Kit includes a barrel with a set screw for the throttle end to eliminate soldering. Choose either the "slow" or "fast" throttle, with or without grips.
This universal throttle cable kit from Venhill comes with everything needed to create your own custom throttle cable.   Outer housing and wire are over 4' long with an array of fittings.  Slide end is already attached and a solderless throttle end is included

Throttle Cable Kit Options
Venhill Universal Throttle Cable
We have all other OKO carburetor parts available on the "Parts and Accessories" page as well as accessories like shocks, bars, electronic ignitions, etc...

Shipping cost for carburetor kits is included in the price.
Air Filters 
We are offering  UNI 2 stage foam filters to fit the K-104 series of carburetors (32mm-40mm) and the K-101 series (19-30mm)  They are angled 15 degrees and are 4 inches in length. We are also offering a K&N style filter (3"x3") for the K-101 series. Select the right filter for your carburetor from the drop-down box.
Choose Filter
Cable Operated Choke Levers
For bikes that have poor access to the regular pull choke, OKO has this conversion kit to change over to a cable operated choke.  It comes with a straight top with an adjuster.  We also have a short Domino lever for handlebar mounting.  It also comes with an adjuster.  These can be purchased separately or together.  If you also need a cable, it can be ordered from above (Venhill Universal Throttle Cable).
Throttle Options

K&N Style

Metallic K-101 Carburetor

Select Destination, Including Shipping
Size of Metallic K-101
Jetting if it is known
Extra Jets Kit
Throttle Options
Slow or Fast Throttle
Shipping Costs
Parts orders within the USA under $20 require a $5 shipping fee.

Curved Top
Clear Float Bowl
Manifold Adapters and Sleeves
OKO K-101 and K-104 Cable  Operated Choke Kit
For bikes that have poor access to the regular pull choke, OKO has this conversion kit to change over to a cable operated choke.  Comes with a curved top, and we also can provide a straight top if desired.  This choke kit can be used with either lever below, as well as our Venhill Universal throttle cable
Cable Operated Choke