I refill the bike while its on the sidestand. Then only up to the neck. What I have discovered is if the bike is overfilled, then the vapor valve gets clogged. When it gets clogged, fuel will leak out of the tank and other places on a hot day.

 

If you fill the high tank first, you can`t waste any time after you are done filling the low tank before you put the cap back on, because it will overflow, remember, the fuel will continue to flow from the high tank to the low tank, even after you have filled it up to the top...

Fill the low tank first, then fill the high tank, leave the cap off the high tank, it will not overflow.

Why do it the hard way. Do it the way the old guys have been doing it, it`s safer.

 

Low side first, then cap it, then high side. one to one and a half inches below (if filling on the stand and not level) this leaves room for expansion.

 

The only thing I can think is that I am not trying to get as much gas in the tanks as you are.

I have overfilled my tanks and had it overflow doing it your way. Doing it my way I have never overfilled it.

 

Thanks for all the replys guys. Very interesting. I do fill the low side tank first, as the tank vent is on the right tank cap. The left tank cap is sealed. I have never had a problem as long as I just fill to the bottom of the filler insert on both tanks. I really don't worry about it to much as I get around 48 to 50 mpg, and with 5.2 gal., I can run 200 miles without going on reserve. My body likes a break at about 100 max. LOL

 

Yep. Some of don't have split tanks.

 

Me too, all the way and sometimes I run it over. I need all I can get, sure not 50 mpg here!