Motorcycle Repair: 1974 CB450 Fuel Lines, honda cb450, vacuum hose

Question
I'm unsure of the orientation of the fuel lines between the carbs, petcock, and tank. Also what size lines I need to use. (Clymer isn't any help at all)
1974 Honda CB450 (twin)

Thanks, Chris

Answer
Chris, you have to go to a m/c shop and see if they have some 5 or 5.5mm fuel line, which is what Honda used originally. A lot of dealerships don't seem to carry it, however, but it is available in bulk from Honda. 5mm is about .200" so you would have to use 3/16" SAE size, but the wall thickness tends to be too thick to allow the two lines to connect side by side on the petcock fittings. VW fuel hose sometimes works for old air cooled engines, but it isn't very pretty. DO NOT use thin walled vacuum hose, as it will soften and collapse very soon.

Fuel lines connect the left and right sides of the tank together to balance fuel load, then the two parallel fittings take lines that go from the petcock down to the carbs. You have to be careful not to route the lines in a way that interferes with the choke linkage running between the two carbs.

Bill Silver
www.vintagehonda.com