I’m using a Pingel Power-Flo On-Off “Race” fuel valve with a 5/16″ outlet. My Mikuni VM30 carbs are designed for a 5.5mm ID fuel supply hose. Given the size mismatch I needed to find a way to step down the hose size from fuel tank outlet to carb inlet. To do this I routed the fuel as follows:

1. From petcock through 5/16 Tygon F-4040-A hose to Jiffy–tite dry break fuel system quick disconnect (-5 AN inlet, -5 AN outlet).
2. From quick disconnect to Pingel 1-in 2-out fuel filter. Conveniently, the fuel filter is 1″ in diameter so I use a stainless steel 1″ EMT conduit clamp to secure it to the bike.
3. From fuel filter to a pair of quick disconnects (-5 AN inlet, -3 AN outlet).
4. From quick disconnects through 3/16 Tygon F-4040-A hose to Mikuni carbs.
5. All hoses are secured using spring clamps.

This setup allows me to remove the tank and the carburetors quickly and easily without spilling any fuel or dealing with hose clamps.  Plus it’s all totally hidden with the tank and seat in place.  Not that I’m worried about historical accuracy or anything with my build.  But it is nice to have everything clean and sanitary.