How much Sea Foam to use in a 6 gallon fuel tank on a 2023 Harley Davidson Street Glide Special? [SOLVED]

Thanks for the question, Don.

For your 2023 Street Glide with a 6 gallon tank, here are a few good guidelines:

For regular preventative maintenance:

Add 1 ounce of Sea Foam per gallon of fuel (so about 6 ounces for a full tank).
That will help keep the fuel system clean and prevent gum and varnish from forming.

For cleaning (best way to get the most out of a can of Sea Foam):

The best way to get the most cleaning power is to use a higher concentration. Here’s what I’d do:

• Wait until the tank is low (1–2 gallons)
• Add a full 16 oz can of Sea Foam
• Ride it for at least 10–20 miles before refueling

That gives the treated fuel time to work through the system. The higher concentration works much better and faster to clean fuel residues and deposits.

For storage:

Add at least 1 ounce per gallon before storing the bike. Sea Foam will help stabilize the fuel and prevent gum and varnish from forming while it sits.

You don’t have to be exact with measurements. Sea Foam is petroleum-based and okay to use in higher concentrations.