I average 42-43 local riding. 46-48 2 up on longer rides.
You can take a center punch and put 3-4 holes in the neck near the top. I still leave a bit of vapor space especially if I'm going to park it real soon. If I'm on a trip then I'll fill it a little more.
This is a good idea, punching holes in the neck. Apparently it's strong enough to handle the impact? Also, any concerns about the need for a brass punch to avoid a spark? I'd be tempted to drill rather than punch if not for concerns about shavings in the tank. I'd think that even a single hole would be effective.
Not sure I'd want to drain and dry out the tank but possibly a good choice. Even running the tank low and filling the gap with a rag, not allowing it to touch fuel, would be a good choice. The former firefighter in me is always thinking about disasters, LOL.
I'm thinking about punching a hole(s) and then scribing a line on the filler neck that I can use for reference when filling the tank. That'll allow me an accurate check of mileage. And yes, I always go by the gallons put into the tank, not the tank capacity, when checking mileage.
My question about capacity was really just regarding where that 5.3 gallon capacity was measured from by Yamaha, the bottom of the neck sleeve or when the tank is filled to the rim of the cap opening itself?
And also, does anyone know of any kind of fuel overflow canister, such as a car would have, that an overfill of fuel would be flowing into without our knowledge? When I pulled the tank off I only saw two types of outlets, the vapor tube that runs out of the bottom of the tank and some kind of tube that sticks out of the top front of the tank under the gauge panel. I've never seen fuel running out of anything after filling it high.