Preparing your Bocar FST Carburetor

The current rules require a Bocar 34 PICT carburetor. For the most part the only thing on the carb that can be modified legally is the external removal of pre-heating components and the choke plate and shaft.  (See photos below.)

  1. To remove the choke plate and shaft, first remove the two screws that hold the choke to the shaft. The easiest way to do this is to use a screwdriver that is the precise size for these screws, put it into the slot and hit it with hammer. (The screw slot is usually peened closed). This blow will open the slot and loosen the screw. Holding the screwdriver in the slot VERY tightly, back the screw out. If you don't do it this way, you will probably mess up the head of the screw and have to drill it out.

  2. Now remove the choke plate.  There is a brass press-in where the idle speed step plate. This can be pried out.

  3. Next remove the 3 screws on the choke pre-heater. Remove the associated components and then remove the choke shaft. Do not dispose of the brass press-in or the idle step plate. The rest can be discarded.

  4. Next unscrew the idle bypass valve solenoid. Do not dispose of it.

  5. Cut the small shaft on the idle bypass valve with a wire cutter and pull it out.  Now using a hack saw, etc. cut the head and threaded section of the valve off. You can dispose of everything except for the threaded unit.

  6. Fill the full hole on this threaded unit with RTV. Set it aside. It will be installed in the carb after drying to plug the bypass hole in the carb.

  7. Using a band saw (or mill as we do), remove the full side of the carb where the choke pre-heater was.

  8. Re-install the threaded plug with RTV.

  9. Press in the brass unit with the idle step plate.   You will probably want to replace the idle step plate with a couple thick washers. Or you can use it, but you will have to JB-Weld it etc. to keep it from turning.
     

  10. You will want to pull out the brass Fuel Inlet (press fit into the carb). You should tap this for a 1/8 npt barbed or AN fitting for safety reasons. (after some time the stock press fit unit can come loose.)
     

    More coming................   

Other than jetting, you are complete.  Depending upon your carb, you will probably have to increase the jet size of  the main slightly. 

 

   

Note: You can also purchase a FST converted carb from SR Racing ready to go. This carb will have all the above conversions, plus will be dyno tested and jetted. 

More jetting info and photos to be added..........    

Remember that you will need an FST Official Restrictor Plate. (available from SR Racing)