Dude, that's perfect!I've got the Motion Pro quick disconnect on my 51. 5/16 for the main line (the actual line is small, it's just covered in a thick rubber sleeve). I run one of Thorsten's airboxes so I cut the main fuel line 6-8 inches from the throttle body union and plumbed in the quick disconnect. I've also got a 1/4 inch disconnect for the return line but I haven't fitted that one yet. It's been on the bike about a year and no leaks, no issues and totally compatible with pump fuel. I use the single sided dry break with the dry end on the tank side (not much to leak on the throttle body side).
If you admit I'm a genius I might even have a spare I could send ya...Dude, that's perfect!
Your the second person that uses the motion pro one that said it works fine. Yeah, the single side shut off should work perfect.
So, I'm looking for 5/16.
I tried these, will report on quality and application....I'll check that out.
I also found this:
LCD17005 - 5/16 Hose Barb Valved In-Line CPC Coupling Body
Looks pretty promising.