Evo Fuel Tank and Petcock Replacement

Mike is in the home stretch with the top end rebuild of our 1988 Heritage Softail. Compression (air), ignition (spark), and fuel are needed in order for any motor to come to life. Mike has already covered the potential for compression and ignition. The intake manifold and an updated CV carburetor have already been installed, replacing the original “butterfly” carburetor. Now, Mike is preparing to re-install the stock Harley-Davidson Evo fuel tanks.

Prior to Evo fuel tank installation, it is important to inspect the fuel valve screen and the overall petcock, or fuel valve condition. If the fuel valve is difficult to operate or is leaking, it should be replaced. If your Harley-Davidson had a vacuum fuel valve, we suggest that the replacement petcock is also vacuum operated. This way, if the carburetor float or needle valve ever get stuck open, gasoline will not overflow onto the ground or through the intake manifold and down the cylinders. Pingel manufactures a vacuum-operated vacuum fuel valve. Another excellent fuel valve manufacturer is Golan.

Remember, if looking to purchase a petcock replacement, it is very important to purchase a petcock that has the correct output direction for your application. Harley fuel valves are always left side. Options are forward facing, downward facing, and rear facing. Unless a custom fuel tank is being installed, the same style valve should be purchased. It is also important to inspect fuel tank grommets prior to tank installation. Grommets should be replaced if they are dry, cracked, or have become hard. Mounting the fuel tanks with the correct mounting hardware is also very important.

The rear Evo fuel tank mounting points use ⁵⁄₁₆” fine thread hex bolts and it is important that the appropriate size washers are installed above and below the rear mounting grommets. With the Evo fuel tanks now installed, Mike will install the dash assembly and hook up the negative battery cable. The spark plugs will be temporarily removed in order to prime the oil system. After confirming oil pressure, Mike is ready to reinstall the spark plugs and fire up this fresh motor for the first time.

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