Blue is atmosphere. Red is overflow past the filler neck ring.
1. Blue has to be open Red closed.
2. Red can be open, blue closed.
3. Both open will work also.
Red: Can push gas into the hose and it sits there. Might eat the rubber and not evap soon but sit in that line. If you vented it, she is dry, no buildup to leak on hot pipe/etc.
Red: Dumps vapor/raw gas; down into the charcoal canister. This can make the bike run rich, cause poor driveability.
Blue: Can only push/pull air [as does red], or keep the tank from imploding or vapor locking; without that blue dot vent being open, you close the red as well.
White: Remember, this is to drain the water away from the gas filler, be it from rain or washing the bike.
White: Has no internal effect venting the tank. Blue and red are the tank vents only, or the right two bottom nipples.
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