Do you rely on floats to shut off fuel?

[beechfront]

I rebuilt my carbs and they're still leaking. took them apart several times to make jet changes and cleaned the float valves every time. I blamed the carb kits as being crappy, but maybe I shouldn't rely on them to do that .

[sixtysix]

YES, the float valves should shut the fuel off, everytime, without question. You can't leave leaky float valves in there, gas contaminated oil and the resulting engine failure is the usual result. It is easy to find out if they seal proberly, just flip the dry empty carbs upside down and blow air in the fuel inlet, if it seals like this then the needles and seats are working and you have a sticky, leaky, or misadjusted float.

[beechfront]

well i set the floats according to the specs in the book. book says something like 25.6 +/- 1mm. according to my digital caliper, i have them about +/- 0.2 mm. I don't think the fuel leve is too high, but even if it were - does that cause it to leak out of the carburetors? I thought for it to leak out the valve must be leaking. Another wierd thing is i've only noticed it leaking when on the centerstand. I don't want to install an in-line valve because I'll forget to shut that off. I was thinking about rigging up some sort of electronic valve.

[Ken Talbot]

There's still nothing like the reliability of properly-functioning petcocks (on a standard) or octopus (on a special). Yes, these things can be a pain, but they can be fixed, and they will provide an absolute shut-off so you don't need to worry about the float valves or having to manually turn them on and off.
"If it's broke - fix it"

[Jerry]

Have had my XJ for 3 years now, don't think I've use the shut off on the petcocks more than 2 times.

I rely on my float valve and octopus to shut off fuel flow, and have never had over-flowing carbs or gas in my oil.

As Ken indicated, a properly functioning system does its job well.

[beechfront]

Yeah the smart thing would be to just spend the money and fix the octopus, BUT THAT'S NO FUN! I was looking at these fuel solenoids used for NOS but I don't think they were designed for prolonged use. In the end, what will most likely end up happening is I will spend money trying to rig up something of my own design, only to find out it won't work and then spend even more money fixing it right like I should have from the beginning.

[MartyA]

8th year of ownership and I have never had the petcocks off, and they don't shut off. Just lucky I guess, only had one occasion at spring startup that I had a leaky float, only had to start it up and the leak went away.

Where's you sense of adventure?

[Bob Falter]

I just rebuilt my carbs because they leaked if I didn’t shut off the gas. I have never had a bike that I had to shut off the gas and that is dating back to a 1952? Aerial 500 single (first bike and I should have kept it). After the first night that I had the XS11 (about a gallon on the floor) I have been pretty good at shutting it off. Pretty good for me means that I have only had gas on the floor 2 or 3 more times. Then there was the time when it was hard to start because I forgot to shut off the gas while I went shopping. One thing I have found on the 79 Special. If it is on the center stand the gas runs both direction, on the floor and into the engine. If it is on the side stand it only seems to run onto the floor. I ran almost 2 gallons on the floor once, with when it on the side stand, but the oil level never change a bit.

Anyhow, back to what I wanted to say. I eliminated the octopus because I figured that you never know if it is working of the needle and sets are working. You only find out when they both fail. I only relied on the needle and set on my other bikes. That is what I want to rely on with the XS11, though I have to admit, none of my other bikes had four carburetors. I pressure tested the needle and sets to about 2.5 psi after I was done with the rebuild (in the driveway with gas). Had no leaks. Today I left it set in the driveway for a couple of hours with the gas on and a full tank. It stared fine but didn’t want to idle right way. Made me think it was running rich, like in flooded? Not sure will try again but now it is in the garage with the gas off. I definitely plan to never put it on the center stand without shutting off the gas.

I’ll typed too long, I better quit.

[Bill__Woods]

on my 81 special, I used a K&L fuel petcock rebuild kit, which came with a new diaphram for the Octopus. I never shut my petcocks off and it never leaks gas.
at only about $35.00 for the rebuild kit, why cobble up a good thing?
my 2 cents...

[Ken Talbot]

Remember, though - in either the octopus or in the standard's petcock, the part that actually shuts off the fuel flow when the engine is not running is the o-ring. Further, the o-ring only works as well as the spring that is pushing against it. You can replace the diaphragm, but if the o-ring is perished, or the spring has gone weak, you're still apt to have a leak. The o-ring or the spring can be replaced with generic replcements from most automotive supply houses for cheap. If the diaphragm is not torn, and if you don't have fuel leaking around the handle of the petcock, you can do without a rebuild kit.

[beechfront]

I'm not sure yet, but I have a feeling I will end up rebuilding the whole thing. I started to take it apart the other day and stopped - it was stuck together pretty good and felt like if I pulled any harder something was going to tear. Probably going to soak it and try again some other day. Rebuild Kit which does both petcocks and diaphragm is $30 and local parts store will sell me a new diaphragm for $60.

[Ken Talbot]

It sounds like you're having trouble getting the diaphragm to pull loose. Use a blade from your feeler gauge (anywhere from .005 - .010) and work it in very carefully between the rubber and the body wherever it appears to be stuck. Free up just a corner at first, then work slowly all around until the entire thing is free. If you try to just yank it free it will rip for sure.

[RiskyBusiness]

I ordered the octopus/petcock rebuild kit from Cycle Recycle and it works well... I think. It could just be that my float valves seal well (which I tested and they do). I left the bike in the drive last night with the fuel on and no smell of gas this AM. This afternoon I will put in on prime and let it sit just to make sure the floats are closing. I didn't test my octopus after rebuilding it so for all I know it is not stuck in the open position. But no leaks, so I am happy.

[ksissom]

I finally got my carbs close to being jetted right and no leaks - petcocks rebuilt and not leaking and I'm bumping up to the next size pilot jets when I notice my #2 plug is a bit sooty and the pilot screw aint doing what it used to do just last week using my new colortune gizmo. Turns out fuel is now being sucked into #2 cylinder through the vacuum switch diaphram. I guess I caught it just as it was starting to deteriorate because it was still opening up and letting fuel go to the carbs too. Mike Hart had the right idea/solution (Fuel shutoff, replumbing & individual filters). The hell with that octopus and two petcock setup. If the floats are cutting off fuel like they should I'll never miss that vacuum switch and besides I always used to turn off both petcocks and now there is only one to turn off. It's clean, it's simple, I'll never have to replace the vacuum diaphram and the original petcocks will probably last a lot longer not twisting on them all the time. The new shut off valve is a ball cock type so it should last a long time too. I knew I would eventually do this when I first saw the thread a few months ago.

[RiskyBusiness]

Originally posted by ksissom
... I notice my #2 plug is a bit sooty and the pilot screw aint doing what it used to do just last week using my new colortune gizmo. Turns out fuel is now being sucked into #2 cylinder through the vacuum switch diaphram...

I am really glad you posted this. I noticed yesterday that my #2 seems richer than my other cylinders. I sort of scratched my head and thought that I should check it with some clean plugs. I wonder now if my vacuum valve is doing the same thing yours is. I will certainly check on that.

Thanks for the post.

-j