Bultacos: Alpinas, Sherpa Ts, Sherpa S, Fronteras, Matador, Pursangs, Metralla 62
To date we have probably fitted more Bultacos with OKOs, both the K-101 series and the K-104 series, than any other brand of motorcycle.  In the sixties some Bultacos used spigot mount carburetors.  Through the mid-seventies, most used flange mount carburetors, and after that Bultaco went to all spigot mounts.  We have kits for many models, including the 250 and 350 Alpinas, the 250, 326 and 340 Sherpa Ts, 250 and 370 Fronteras and the 370 Pursangs.  For other models, we just need to know the manifold size and the model you need a carburetor for.  Photos below show kits for both flange mount and spigot mount models.  If you don't see what you are looking for, contact us at usaoko@comcast.net or call us at 410-635-6722. 
After testing and evaluating OKO carburetors on Bultacos for about nine few years now, we are fitting 26mms on most Sherpa Ts and Alpinas.  The 340 Sherpa Ts and the 350 Alpinas have also worked well with the 28 and 30mm sizes.  We have been working with the pilot circuits to eliminate the "flat spot" sometimes experienced with the 326 Sherpa Ts when using larger than the 26mm.  For those who must have more top end we now offer the 28 and 30mm for these Sherpas.  Below you will find kits for a variety of Bultaco models.  Let us know of any modifications you may have, as these will affect jetting.
Flange Mount for Amal Concentric Replacement: Bultaco
Remove manifold studs.  Photos shows the rubber adapter with a rubber insulating block; attach with 8mm x 25mm allen screws.
Insert spigot end into adapter , adjust for vertical (match lines top of adapter and carb), tighten clamp and viola!
Click On Small Photos For Larger Ones
Flange Mount Kit with jetted carb, extra main jet, flange adapter with hose clamp and mounting bolts.

This kit is for replacing the flange mounted (See photo to the left) AMAL Concentric  carburetor. Tell us which Model you have, whether it is a 250cc or 350cc and select the appropriate shipping destination.
Select Destination, Including Shippping
Model Type
Select Carburetor Size
Optional clear float bowl
In Stock
OKO K-101 Clear Foat Bowl 
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.  This may be purchased by itself or with a K-101 Carburetor kit.  Click on the "options" below.
Clear Float Bowl Options Including Shipping To:
Carburetor Size
For the 250 Frontera we use the 32mm.  For the 370 Frontera we use both 32s and 34s depending on whether we want low to mid-range or top end power.  Choose your size according to your riding.    Keep in mind that the 32mm is no slouch on the top end; the 34 is just a bit better.
Above: Bore of 30mm is taller that it is wide, giving the same low end power as the 28mm, but with more top end
Select Destination, Including Shippping
Size of carburetor Desired
This kit is for replacing the Bing and AMAL MKII carburetors on Alpinas and Sherpa Ts that are spigot mounted (See photo just to the left).  Tell us the size and model of your Bultaco and select the appropriate shipping destination.
OKO K-104 Carburetor Kit
For  Frontera 250s and 370s 
Select Kit and Destination
Size Carburetor
Model # & Modifications
OKO K-101 Carburetor Kit
Model 10 Sherpa Ts
The Model 10 Sherpa T came with a spigot mounted IRZ carburetor.  Depending on how you wish to mount the OKO we offer different kits.  You can select which kit you want below.
The easiest way to switch from the IRZ to the OKO is to use the existing manifold (bottom photos). Most or all of the end needs to be cut off in order to use the sleeve as seen above.  Then the OKO can be directly mounted to the stock manifold via the rubber sleeve.  To keep from modifying the stock manifold, we opted to use a later flange mount manifold in its place.  This requires some modification of the manifold and a couple of the cylinder's fins for good clearance.  We offer a kit for either manifold.  If you need the flange manifold we do have them in stock as well.  We also offer the Venhill cable with the kits at a reduced price.  See below.
Select Destination, Includes Shipping
Type of Mount: Spigot or Flange
Throttle Cable Kit Options
OKO K-104 Carburetor Kit
For  Pursang 250s and 370s 
Select Kit and Destination
Model # & Modifications
OKO K-101 Carburetor Kit
Sherpa S 200
The Sherpa S 200 uses a 28mm OKO.  Our kit contains the carburetor jetted for the Sherpa S, plus extra jets for fine tuning and elevation changes and a flange adapter.  This kit outperforms the stock carburetor by quite a lot.  Our bike did not have an air filter, and the ones we have are too long, so a "pancake" type filter will need to be sourced.
Select Kit and Destination
Flange Mount Kit
For Alpinas and Sherpa Ts
Spigot Mount Kit
For Alpinas and Sherpa Ts
OKO K-101 Carburetor Kit
Matador 250 
Matador 250
We have a kit for Matador 250s.  Shown is a MK4.  The kit should work for MK3s and MK5s which are also 250s.  We use a 30mm OKO and provide a flange adapter for the manifold.  The existing airbox hose will work but will need to be cut back a little.  The throttle cable will also work but the top adjuster will need to take some of the play out of the cable.
OKO K-101 Carburetor Kit
Metralla 62, Model 8
We replace the 27mm AMAL monoblock, the stock carburetor for the Metralla 62, with a 26mm OKO.  It is jetted for the Bultaco and the kit contains a flange adapter as well as extra jets for fine tuning.  We also offer this kit with the air filter as seen in the photo, since there is not a lot of space behind the carburetor.  To the right, you can select the shipping destination and whether you want the standard kit or the kit with the air filter.
Select Shipping Destination
Add the Air Filter to the Metralla kit Order
Price: $15.00