dual fuel cutoff valve...?

[thejuggster]

I am getting back into the 2 wheeled fun after many years of not riding. I bought a 1979 XS 1100 SF and already fell in love with the ride and the bike.

I noticed my bike has 2 fuel cutoff valves. Do these work independently?

[DiverRay]

Yes. There may still be a vacuum cutoff switch mounted on the #2 carb as well.
Welcome to the site. If you go to the MAIN forum page, you will find the "tech tips" on the left side. You can read about the bikes, and find the most common questions will be answered. In fact, you may find more than you ever wanted to know about the bikes here!
With you location, I expect you are not riding much for the next few months. I expect you will have time to read through, and probably do some mods to your bike. Don't forget to read up on the "picture posting", as most of us like to see pics of the different bikes.

[mro]

petcock to carb diagram

back into the 2 wheeled fun after many years of not

Been there....Got here, sorta by accident. My first XS was a 80G. If not for the G would probably be riding a Hardley although was not in any hurry to get one. Must just be a XSive at heart


mro
BTW, welcome to XSland

[van]

Re: dual fuel cutoff valve...?

Originally posted by thejuggster
I am getting back into the 2 wheeled fun after many years of not riding. I bought a 1979 XS 1100 SF and already fell in love with the ride and the bike.

I noticed my bike has 2 fuel cutoff valves. Do these work independently?

Hey!

Welcome,

I'm waiting to take delivery of a 79 black XS1100SF this week.
I've been looking around this site a bit and have found lots of great stuff about our rides.
The oil filter mod (allows you to use a spin off car style oil filter)and the 750 mod (differential replacement using a XS750 rear end) are the first things that I would like to do.

I never noticed the dual pet cocks but like I said I don't have the bike yet. I've read about a device called an Octopus, could this be part of the dual pet cock set up?

Van

[van]

Originally posted by DiverRay
Yes. There may still be a vacuum cutoff switch mounted on the #2 carb as well.

Grunt???

Either side switches to the tank to reserve?

Van

[thejuggster]

Originally posted by DiverRay
Yes. There may still be a vacuum cutoff switch mounted on the #2 carb as well.
Welcome to the site. If you go to the MAIN forum page, you will find the "tech tips" on the left side. You can read about the bikes, and find the most common questions will be answered. In fact, you may find more than you ever wanted to know about the bikes here!
With you location, I expect you are not riding much for the next few months. I expect you will have time to read through, and probably do some mods to your bike. Don't forget to read up on the "picture posting", as most of us like to see pics of the different bikes.

yep pretty much thru with riding this year. Thanks for the tip, I will definately be reading ALOT, I have quite a bit of work I want to do.

I just found out that the guy I bought the bike from didnt know it had 2 pet cocks He has been riding it for the last 2 years with the right side off.

[fredintoon]

Hi Juggster, Van,
If you look at mro's diagram, the thing it calls "diaphragm" is what is mostly called the "octopus". It's called that because it's got EIGHT fuel lines going to it plus two tee connectors and a vacuum line.
Many think the octopus was not one of Yamaha's better ideas.
Lose the octopus!
Blank off the vacuum port and the two "prime" fuel nozzles on the gas taps.
Run a fuel line from one gas tap to the tee connection between #1 & #2 carbs and another from the other gas tap to the tee connection between #3 & #4 carbs. You should fit an in-line gas filter in both of these gas lines. (some find that running the left-side gas tap to the right-side carbs and vice versa lets the lines have an easier run. You may also tee into each line and run a fuel line between them so a single gas tap will feed all four carbs.
Now all you have to do is remember to turn the taps on when you start the bike and to turn 'em off again when you stop. Just like in the old days.