Wont Start...

[jomur]

Rode it the other day, next morning would not start. checked for spark, ok. Fuel lines drain on prime...! seems like its not getting fuel. pulled fuel manifold, seems like the little pump is working. but cant see fuel going thru filters. Can prime, and fill carbs, seems like it will run untill carbs empty, if i keep the rpm's up. whats up! Its like im not getting any vacuum to suck fuel to the carbs all the sudden...?

[3Phase]

Jomur, that little do-ma-fetch-it isn't a pump, it's a vacuum controlled fuel valve. Most folks call it the 'octopus' or 'octy' because it has eight fuel hoses!

From what you've described the fuel only goes to the carburetors when the fuel tank levers are set to Prime, then it runs out of gas when you turn them to back Run or Reserve.

There should be a small vacuum line connected to a nipple on the rubber intake boot for the #2 carburetor that runs up to the octy. If that line came off or broke then the octy won't work except when you turn the fuel valves to the Prime position.

[DGXSER]

Another option is if the diaphram inside got a hole in it, the vacuum will not work and open the valve. Inside there is a plunger with an o-ring that is held in place by a spring. The plunger/ o-ring plugs the two holes where the fuel lines come in from your petcocks (the center two lines on the valve). Only when vacuum is applied to the back side of the diaphram (and not to the front) will the diaphram pull that plunger back against the spring and open the fuel to flow from the petcocks. The fuel will then flow to both of the outlets (the outer two lines) to the carbs.

Another interesting thing about the OCTY is it will feed both carbs from only one petcock.

Like Scott described it, when you turn the petcocks to the PRIME setting, the fuel comes out the front nipple on the petcocks which bypasses the valve and goes straight into the T that leads to the carbs. The purpose of the PRIME setting is to fill the float bowls with fuel so the engine can start after draining the carbs to work on them or storing the bike over the winter or such.

[jomur]

Vacuum Hose

That was on of the sirst things i checked, it seemed to be ok when i sucked thru it. and no it didnt come off ether side. can the diaphram just fail, just like that...?

[3Phase]

It could. Or the octy is fine and you have a humongous vacuum leak in the #2 manifold.

If the diaphragm is good you shouldn't be able to keep pulling air through the vacuum line. It should pull vacuum, open the valve, and fuel should flow to the carburetor tees.

If the diaphragm is bad you can buy a rebuild kit or bypass/eliminate the octy.

[natemoen]

The other thing is that it needs to be hooked up to the carb intake boot and not the nipple on the carb body. Wouldn't get much vac at idle.

[BA80]

Jomur, that little do-ma-fetch-it isn't a pump, it's a vacuum controlled fuel valve. Most folks call it the 'octopus' or 'octy' because it has eight fuel hoses!

I only count 4 coming off of mine.

My octy isn't working right either, I'm running out of fuel at highway speeds. I've been running on prime for a month or 2 now. I gotta get that fixed so the fuel will flow through the filters again.

[3Phase]

I only count 4 coming off of mine.

Use your other hand, Greg. There are eight fuel lines and one vacuum line on that sucker....

My octy isn't working right either, I'm running out of fuel at highway speeds. I've been running on prime for a month or 2 now. I gotta get that fixed so the fuel will flow through the filters again.

Hmm, that happened to Roo when we temporarily put a Standard gas tank on his bobber for the Durango rally. One of the fuel taps kept shutting off at freeway speed and had to be set to Prime to keep working.

When we got to motoman's house after the rally and did a quick carburetor synch after cleaning and oiling the sticky vacuum advance bearing on his bike it stopped doing that and it worked fine for the high speed/low drag run up to Washington.

[crazy steve]

You're both right... four lines actually connected to the octy, but by the time you get done running everything everywhere, there's eight; ten if you install filters.... too many....

[BA80]

Use your other hand, Greg. There are eight fuel lines and one vacuum line on that sucker....

I don't care which hand you use, there are still only 4 fuel inlets/outlets on that octy.

Hmm, that happened to Roo when we temporarily put a Standard gas tank on his bobber for the Durango rally. One of the fuel taps kept shutting off at freeway speed and had to be set to Prime to keep working.

When we got to motoman's house after the rally and did a quick carburetor synch after cleaning and oiling the sticky vacuum advance bearing on his bike it stopped doing that and it worked fine for the high speed/low drag run up to Washington.

It's been gradually getting worse. It finally got to the point I had to run completely on prime on the way up to the lost rally. It could be the filters clogging too. I'm just too lazy to get in there and see.

[3Phase]

But... but... ten would make it a squiddy instead of an octy!

[jomur]

You guys are funny..

Havent had a chance to work on her again. But 3 Phase, you mentioned eliminating the Octy altogether. Is that really a viable option? and what are the ramifications...?

[natemoen]

Havent had a chance to work on her again. But 3 Phase, you mentioned eliminating the Octy altogether. Is that really a viable option? and what are the ramifications...?

No ramifications, other than having to manually turn the petcocks off when done riding. Just plug the front nipple on the petcock (or tee it into the other fuel line) and you are good to go.

The front nipple is only prime so no loss there.

[bikerphil]

Octy alternative, it has 5/16" fittings though. I'm gonna try one with my single fuel tap set-up...

http://www.chrome-addiction.com/g-pi...alve-44314.php

[3Phase]

... and what are the ramifications...?

I see the guys have you covered on eliminating the octy!


I'd keep the octy, fix it and put on some new fuel lines before the old ones harden and crack open. Some of the ramifications of eliminating the octy are:

Messy, leaky, drippy, sticky, smelly fuel taps like all motorcycle used to have after turning the taps on and off a few bazillion times before vacuum-controlled taps were invented.

Gasoline will pour all over the engine, the ground and into the engine oil sump the one time when you forget to turn off both of the fuel taps and one or more of the carburetor float valves leaks.

The fuel doesn't shut off and can keep flowing after an accident until the tank is empty.

Could be particularly bad for the people that also removed the tipover switch when they removed the octy or replaced the vacuum-controlled taps on a Standard with manual taps because the engine may continue to run on its side with the throttle jammed wide open and no engine oil pressure while the fuel pours out of the carburetors.