The last lot I fitted earlier this year was R9 6mm. Decent push fit clamped up ok with no leaks. I am running Weber 34ict’s however.
I used Cohline hose from Coolair. They do 5.6mm and 7.3mm for 6mm and 8mm pipe. Fits perfectly. Do use proper fuel clamps rather than jubilee clips.
Jubilee worm drive clips are proper hose clamps – I use them on fuel injection, carbs get the cheap and cheerful nut and bolt clamp. Neither type are perfect, both put an uneven clamping force on the hose but either are good enough.
Trick is always to use a clamp designed for the diameter of the hose you are using, not force a too large clamp to take on a non-circular shape. Of course at 4psi or less most pipes will stay on without clamps at all, if they are pushed on properly. A bad clamp is worse than no clamp. The clamp mostly stops it sliding back over barbs. Dont use clamps to "shrink" slightly loose rubber hose onto a fuel fitting... the rubber can soften and the hose pops off even with 4 psi... did that once when I ran out of the correct hose. Lasted 8 hours...
Maybe a job for the future, but well worth fitting a separate fuel cut off solenoid in the feed from the tank. To scare yourself, fill your tank and then take the feed hose off at pump. Bleeding awesome how quick the fuel feeds out under gravity. Reassuring to know that with a solenoid turning the ignition off isolates it. Plus added theft protection, as they will crank it until the carb bowl is empty and all the crap in the bottom then blocks the carb up good and proper. You just have to remember
Also my solenoid used to play the trick of being sucked closed by the fuel pump so hard that it got vacuum locked down and wouldn't open .. I drove it like I stole it.. usually about 10 feet.. Cured in the end by building a boost converter that fed the solenoid with 32 volts for half a second then regulated at 16 volts normally. Three transistors and some other bits.
