The following modifications
should be made to your fuel supply whether you modify your CV carburetor or if you
change the carburetor to an aftermarket.
In order to improve fuel flow to your
carburetor, you may want to drill out the gas cap. Turn over the gas cap
and look at the bottom. The plastic molding SHOULD have 4 spokes but some of the bad ones
had 8 spokes...8 spoke gas caps need to be replaced with a 4 spoke gas cap then the
modifications can be made. The one with 4 spokes has four pads or flat spots about 1/8
inch in diameter spaced around the outside of the inner molding ring. Using a 1/16 inch
bit or smaller, drill a hole in the center of each of these pads clean though to the
airspace below. Do not get too enthusiastic and punch a dent or hole in the top of your
gas cap. The result will be better gas tank venting now that you are using more fuel and probably
riding harder and faster. There is currently some controversy about this subject so please
read the Denish book for more information.
Due to EPA regulations the stock fuel petcock on late model
Harley-Davidson's has very restrictive fuel flow. There are several alternatives, but
Pingel is far and away the best on the market. Excellent flow and very high quality
construction with a good feel to its movement. The vacuum actuated fuel petcock
on the later bikes seem to be very problematic in restricting fuel flow for
bikes making over 80 horsepower. Replace this
petcock with a Pingle if you are serious about performance.
These modifications are for off-road use only and are not
approved by the EPA or DOT or Bill Clinton. Some people ride on the road with these
modifications, but I would not know who that would be ;-) Also, the authors nor their
descendants nor their ancestors are responsible for any damages due to following these
instructions. If you follow them correctly and do not screw up you will not have any
trouble anyhow, but there it is.