removing octy

[thewiz]

Robert Hollis:

If ya' wanna' change to full on manual taps, look at this link and scroll down the page ... a little more than $50 but not too much more.

https://www.partsnmore.com/cat_index.php?model=xs1100&category=carb

[bwilding_2000]

Okay, I went with ordering the petcocks from parts and more, since one of my petcocks STILL was really hard to turn even after I rebuilt it. I have been leaking gas through carb 1 and I am going to switch out to a standard tank and rebuilt carbs. If I keep the octy and the Standard fuel petcocks for now, is that like having a double safety from fuel leaks?

[XS1100_OEM4ME]

Gas leak

but eventually some fuel would seem to seep it's way past the float valves .. especially when the tank is plumb full and it sits on the sidestand. Since the needle and seats were brand new; I figured that just might have been the reason why Yam engineered a vacuum shut off in there and didn't offer it as an option. Hmmm ... but what would I know?



To my backwards way of thinkin', I figured that: if shuttin' of the fuel taps stopped the leak to the crancase, at the very least, THEY, themselves, work, right? Just the way I looked at it ....

I think you know plenty, Some have had unbeleivabule luck with no octy and no carb leak ever. The stock float needles were never intended as a total fuel shut off, thus, the octy. A costly add. for yamaha, but their eng. team felt ness. I guess some here know more about these bikes the the ones that built them?

[natemoen]

Just turn your petcocks off and then you dont have to worry (unless they leak too). If you have the octy and want to keep it grind off the notch at the top of the petcock valve plate and then you have the off position.

[DGXSER]

I think you know plenty, Some have had unbeleivabule luck with no octy and no carb leak ever. The stock float needles were never intended as a total fuel shut off, thus, the octy. A costly add. for yamaha, but their eng. team felt ness. I guess some here know more about these bikes the the ones that built them?

In my best John Madden Voice "Now heres a guy that can go way back in a thread and pull one out to make a point". (Sometimes I actually am funny, you be the judge this time)

Really though, the theory that strikes me is this: I'm riding my bike and not using much fuel because I am just cruising along at 2-2.5k RPM, my tank is full and therefore exerting the same pressure on those float valves as it would sitting in my garage. So, it would seem that the float valve would never be able to regulate my fuel level in the carbs under this circumstance. Yet, it does. Now pressure over time would typically not have an effect on these valves. Its not really a spring your pushing against that can give in over time, it is the boyancy of the floats which does not change and will always provide a constant pressure for the same fluid level (unless they leak, but then your back to faulty equipment.). So, if all is working well, no need to shut off the fuel to the carbs.

Now, I am also practical about things and know Mr. Murphy REALLY well, so I shut off the petcocks when not in use. It s all opinion though, so to each their own as to vacuum or not.

[bwilding_2000]

one of my Special petcocks had the brass part come right out when I took of the fuel line! Obviously the octy was not working because gas was filling up my airbox. One of the petcocks was a beast to turn anyway. I just want to make sure i have no more leaks! So, I will install a rebuilt octy with the new carbs, a standard tank with octy-petcocks? and new aftermarket petcocks to seal the deal. Am I on the right track?

[DGXSER]

I am a little confused by all of that. Do youhave a standard tank or a Special tank? And petcocks do not work from on to another. The standard tank and petcocks have vacuum valves in the petcocks, so no Octy. The special petcocks have an off position, and one combined vacuum valve (separate form the tank mounted over the carbs) referred to as the Octy.

You only get one petcock per side of the tank, if you use aftermarkets, you would not use the stock ones.

[XS1100_OEM4ME]

under use

In my best John Madden Voice "Now heres a guy that can go way back in a thread and pull one out to make a point". (Sometimes I actually am funny, you be the judge this time)

Really though, the theory that strikes me is this: I'm riding my bike and not using much fuel because I am just cruising along at 2-2.5k RPM, my tank is full and therefore exerting the same pressure on those float valves as it would sitting in my garage. So, it would seem that the float valve would never be able to regulate my fuel level in the carbs under this circumstance. Yet, it does. Now pressure over time would typically not have an effect on these valves. Its not really a spring your pushing against that can give in over time, it is the boyancy of the floats which does not change and will always provide a constant pressure for the same fluid level (unless they leak, but then your back to faulty equipment.). So, if all is working well, no need to shut off the fuel to the carbs.

Now, I am also practical about things and know Mr. Murphy REALLY well, so I shut off the petcocks when not in use. It s all opinion though, so to each their own as to vacuum or not.

While under "use" full gas or just ridding, the carb valves do just what the were made to do "reg." fuel flow. As your bike is using fuel and "vibrating" the valves, gas "goes" to the right level for riding. When sitting, gas flow is stoped from running over by the octy. I am guessing $100 + per bike yamaha $$$$. That would be a few million if I get production # right. Though I am sure you could have saved yamaha those millions of $$$$, they chose some stupid people who just made a bad choise.

[fredintoon]

Complifexation!

While under "use" full gas or just ridding, the carb valves do just what the were made to do "reg." fuel flow. As your bike is using fuel and "vibrating" the valves, gas "goes" to the right level for riding. When sitting, gas flow is stoped from running over by the octy. I am guessing $100 + per bike yamaha $$$$. That would be a few million if I get production # right. Though I am sure you could have saved yamaha those millions of $$$$, they chose some stupid people who just made a bad choise.

Hi '4ME,
nah, perhaps $100 for the prototype but for production units, $17:50 each, tops.
What I reckon is, there's those as wants automatic fuel shut-off and there's those as don't.
And they are both absolutely right.
What I'm sure of is that Yamaha's version has way too many lengths of vacuum and fuel hoses and each one with a clamp and potential leakage point at both it's ends.
There's a reason that Yamaha calls the thing a "central vacuum operated fuel valve" while it's users call it "that f**king octopus"