Don't leave the tank too empty. The hot motor easily heats up the smaller amount of gas into a "gas" and this vent's once the pressure point is reached. I have found with the wife's bike and mine that I if I keep the tank fuller (Not full) the smell stays away. Takes alot more heat to flash off the fuel in the tank to a gas and thus no venting in the garage. Worked for me. Ps....someone else said to do this in one of the 400,000 previous discussions and it made sense so I tried it. Worked. Not my idea.

 

All the above, and if your not stock can also have some unburnt fuel in the pipes...

 

I see your point