This may be a stupid question but... Should Seafoam be used on a full or empty tank? I bought a can and it doesn't specify.

their website says to use 2 oz. Sea Foam to each gallon.

Depends on why you need it. 2oz/gal for moisture control is fine.

1/2 can per tank should clean out the fuel system pretty well.

if your carbs are dirty....drain them and fill with seafoam and let sit overnight...then drain and fill cards with fuel and give it a shot.

I put it in when the tank is low/empty, then add gas and let the inflow mix the stuff around.

You CAN run on straight Seafoam, but it smells awful, and might not be best for the bike...

Hippie

personally i never cares for seafoam in my cars but after hearing every body on hear talking about it i used some on black betty
added about a third of a bottle to a full tank of premium and she pops of a little white smoke when i get into the throttle but she is showing improvements so i guess it is working

x2

I usually put some in every few fillups when the tank is full.

And why have you been using Premium? Just asking.....

I run Chevron brand gasoline in every thing I have. Never have had any problems with fuel related performance in anything I own. One pickup I sold latey had 429,000 miles on it and the only thing I ever did to the engine was one distributor and two water pumps. Never broke any other gasket on her. Pulled two injectors out at 350,000 miles just to check for carbon and they were as clean as new. I guess I'm suggesting that if you use a good quality fuel with a built in cleaning agent you shouldn't need to much carb maintenance.

Well, the PO of my bike left it sitting outside for about 8 months and didn't take great care of it. It has carb issues I am trying to work out. I cleaned out a clogged petcock and that worked for a few days but now I am getting the sputtering and rpm issues back. I'm hoping a couple doses of Seafoam will help.