Topic: Carb bowl drain tubing...what diameter (cb550)

[Gorms]

I dont know why I cant find this info.  Searched here and no luck with microfiche.  Help me out.

[Gorms]

And do I need this tubing to be fuel resistant?  A good idea but probably not right?

[Bob Wessner]

Hmm, the parts list for my 750 doesn't specify diameter. Take a bowl with you someplace to check it and it should be fuel resistant. Even without leaks, it will be exposed to fuel vapors.

[Johnie]

Don't buy them from Honda they are outrageous. I did as Bob mentions and took a bowl off and went to the local hardware store. I did not worry about if it was made for gas or not. I have not had an issue with that. Be sure you know how many feet you want. I think I bought like 6 feet and kept the rest for future bikes.

[Slayer]

1/4" I am pretty sure

[BVCB650]

Mine were dry rotted and half plugged up with mud dobbers nests. I don't have a leak right now, nor do I store my bike. What is the need for them if you are me?

[fastbroshi]

Nope, 1/4 is too small.  Need to go to at least 5/16's od, but then again depending on the manufacturer it may fit.  The stock stuff is 5mm IIRC. 

[Bob Wessner]

I don't have a leak right now, nor do I store my bike. What is the need for them if you are me?

But you might. All it takes is one sticky float valve an a fuel tap left on. The tubes at least keep the leaking gas from collecting on the engine directly below the carbs.

[BVCB650]

Thanks Bob. If I understand you right, they are a safety valve in case there is a leak, or if you decide to drain the bowls. I generally use a tuna can for that.

[Johnie]

Thanks Bob. If I understand you right, they are a safety valve in case there is a leak, or if you decide to drain the bowls. I generally use a tuna can for that.

Now draining the bowls depends on what bike. The early bikes when you drain the carbs from the drain screw it does not come out the overflow tube. The later bikes like I think my K7 when I open the drain screw it would come out the overflow tube.

[BVCB650]

On mine, if you tip the carb/bike over enough, gas will come out of the little nipple where the hose goes. For draining, I simly loosen the screw to allow gas to come out the same nipple.

[fastbroshi]

The 550 carbs have these overflow tubes in case the petcock is left open.  There's a dedicated drain screw on the outboard side of each carb. 

[Gorms]

Yes my drain tubes are also the overflow tubes.  I did take the bowl off and took it to a bike shop.  I got 1/8" tubing (small I know but it slides on nice and snug) for 50 cents per foot, versus $3.50 a foot for the honda stuff that they also had.  I'm good to go.