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CNS Carburetor Adjustment and Tuning Guide

Who doesn't love flying down the road on a motorized bike- the wind in your hair, the rush of adrenaline as you pull on the throttle... Nothing gets your there better than using a CNS High Performance Carburetor! However, those carburetors are set up differently than any other bike engine kit carburetor on the market. We know how tricky those can be to install, so we've created this guide on installing your new CNS carburetor to help you better understand and run your new carburetor.

CNS Carburetor Adjustment Guide


  • Begin by removing the top cable plate.
  • Disconnect choke cable from the lever.
  • Slide the choke cable into the cable plate from the reverse side.
  • Slip the choke anchor into place.
  • Slide the choke housing back on and connect lever.
  • Install the throttle cable into the top plate.
  • Install the large spring and connect cable anchor into plastic throttle slide.
  • Release the large spring.
  • Insert the slide back into the carburetor
  • Install screws and tighten down secure making sure gasket seats correctly onto the carburetor.

The CNS High Performance carburetor has a larger intake manifold port than other carburetors, so you may find that the plastic bushing that comes with most CNS carburetors might still need some more room in between the manifold and the port. If this is the case, most riders find that 1/2" thick PVC piping fits around the manifold snug and can prevent the carburetor from vibrating or slipping off during riding.


Performance carburetors also run differently than other carburetors out there. The CNS High Performance carburetor might prove to be a little trickier to tune and require more finesse. You’ll want to be sure to try the following before operation:

  1. Set the adjusting screw all the way down.
  2. Remove the metal plate that houses the slide and jet needle attached to the carburetor.
  3. Set the jet needle valve C-clip to its highest setting (the setting that allows the jet needle to go in the furthest).
  4. Turn the adjusting screw 6-8th of a turn out.
  5. Test the bike by riding it.
  6. If the engine is bogging, fuel leaking from the carburetor, or any improper performance, stop the bike and turn out the adjusting screw another 6-8th of a turn.
  7. Repeat steps 5 & 6.
  8. If you screw the adjusting screw all the way out with no satisfactory result, set the C-clip on the jet needle to the second setting, set the adjusting screw all the way down and repeat steps 4-7 until you get desired results.You want to keep doing this process until you receive desired results. When you tune it correctly, your carburetor will not only run well but run fast. Always be sure to wear your safety accessories while enjoying your engine and newly tuned carburetor!