Simplified Tuning | Boyesen Engineering Twinshot

The Twinshot is available in black and polished aluminum finishes.

Boyesen Engineering, based in Lenhartsville, Pennsylvania, has manufactured products for motorcycles, snowmobiles, watercrafts and more since 1972. Founder and President Eyvind Boyesen aka the "Reed Man" is committed to offering innovative intake products for the powersports industry.

Recently, for the V-Twin market, Boyesen introduced the Twinshot (179.95), which replaces the stock float bowl on '92-06 Harley-Davidson CV40 carburetors and creates "a synergistic effect that will make the carb respond as if the bike was fuel injected. The combination of the 5 percent stiffer activation arm spring and the precision plunger rod ensures that when the throttle is turned, the plunger rod acts upon the diaphragm. This forces fuel into the dual sprayer and squirts a twin shot of fuel directly into the bore of the carburetor," according to Boyesen. The result: it eliminates throttle hesitation and bogging, which causes your carbureted system to simulate a fuel-injected system without the electronics.

The Twinshot unit is very easy to install, requiring basic tools that any enthusiast could do at home and didn't take much time to swap the stock float bowl out for the Twinshot.

1 We started by turning the fuel off at the petcock, then removing the air cleaner assembly. We then removed the carburetor from the intake manifold to remove the stock float bowl.

2 Four bolts hold the float bowl to the carburetor. We simply removed them one at a time and placed a cup underneath the carb to catch the remaining gas when we removed the last bolt. The bolts were reused for the installation of the Twinshot.

3 The Twinshot (left) has an adjustable leak jet on its accelerator pump housing (yellow arrow) whereas the stock float bowl (right) has a fixed .40 hole to relieve pressure when the accelerator pump is activated, which sprays the same amount of fuel at all times. The Twinshot's adjustable leak jet allows you to control the fuel spray. By turning the screw counter-clockwise you lean out the accelerator pump for better throttle response in higher elevations/hot days, or on cold days/lower elevations turn the screw clockwise for a richer mixture and better response.

4 Also, look at the difference of the sprayers. The stock application uses one sprayer (left), and the Twinshot uses two sprayers (right). Boyesen claims the dual sprayers increase velocity to improve fuel atomization.

5 We removed the fuel overflow/drain hose from the stock float bowl and installed it on the Twinshot.

6 We then removed the stock plunger arm and plunger arm boot from the carb. Both were not reused. The cotter pin was removed from the pump rod in order to slide the stock spring off.