Gas tank

[mmaddix]

I have a question about my gas tank. I don't know if it's original or not but my petcocks have two places to hook up the hoses to the carbs, one is for the primary and one for the reserve. I only have the pri hooked up. When I switch it to res, without a house hooked up, no fuel flows from them. I have even put the hoses on the res and fuel still didn't come out of them. Am I doing something wrong and once I get fuel to flow how can I have both the pri and res hooked up so I can just switch it while I'm riding if it stats chugging. Can I just put a 2 into 1 fitting on each side or will that not work.

Thanks everybody. I hope I have explained this good enough.

[crazy steve]

There's two petcock types; standard and special, and they only fit their respective tanks. If you have the teardrop tank with the off-center gas fill, it's a special. If it's a squarish tank with the flush gas fill, it's a standard.

The special petcock has two fuel line connections, both pointing down. It will have off/reserve/on/prime positions for the lever. You'll get fuel flow in any position (except off) with the hose(s) off. If not, it's clogged internally. The front hose connection is prime, the rear is on/reserve.

The standard petcock has two hose connections, both pointing 'in', but only one (the larger one) is fuel. The other hose is a vacuum line, which should be connected to the hose barbs on the 2/3 intake boots. You'll also have on/reserve/prime positions, but no 'off'. Without the motor running (and the vacuum lines connected and the petcocks working right), you'll only get fuel flow on 'prime'. You can test these by hooking a hose to the vacuum connection and sucking on it; if you get fuel on either 'on' or 'reserve', the petcocks are good. If not, the internal diaphram is bad and they'll need to be rebuilt.

[CatatonicBug]

You have a Standard, so your petcocks should only have one fuel line on each of them. There is one Fuel port and one Vacuum port (that connects to the carb boot). Remember that fuel only flows with the engine turned on. Or at least when you are applying vacuum to the vacuum hose on the petcock. There are 3 settings on the knob - On, Reserve, and Prime. Prime is the only one that bypasses the vacuum requirement.

The Specials have 2 fuel ports and one vacuum port. In this case, one of the fuel ports is the Prime port. However, in neither the Standard or the Special Petcocks is there a "Reserve" fuel port.

Edit - Sorry Steve, you typed faster than me.

[crazy steve]

...The Specials have 2 fuel ports and one vacuum port...

No vacuum port on the special petcocks, the vacuum control is done separately at the 'octy' if you have one, which I doubt.... sorry 'bug

[CatatonicBug]

No vacuum port on the special petcocks, the vacuum control is done separately at the 'octy' if you have one, which I doubt.... sorry 'bug

You're right. I was typing too fast, and missed that. Thanks. And yes, I have the octy.

[crazy steve]

...And yes, I have the octy.

I figured you do, but if Maddix has a swapped tank, the octy doesn't seem to make the trip very often....

[mmaddix]

Ok this all makes since I don't have any hoses hooked up from the carb boots to the petcocks and that's why mine only works in prime. If I put some hoses on there and everything works as advertised what does each of the positions do? I'm guessing on is for your primary and reserve fuel. Is this correct?

Oh yea I forgot to tell you I do have a standard tank. Or at least I think I do because the gas filler cap is in the center and not of to the side.

[DGXSER]

PRIME allows fuel to flow to carbs when the engine is not running, no vacuum required, it also eliminates any reserve, so when you run dry in PRIME, your dry and walking.

ON requires vacuum to allow fuel to run to the carbs, and keeps the reserve function intact. When you run dry in ON turn it to RESERVE and you have some fuel left to get to the service station. RESERVE also requires vacuum from the running engine to allow fuel to flow to the carbs.

[crazy steve]

Set your petcocks to 'on'. This will draw fuel down until there's about 1/2 gallon left, when you'll want to go to 'reserve'. The 'prime' function is there so if you run completely out of fuel and the motor won't start, you can fill the carbs manually. Both reserve and prime draw from the same level, so you don't want to ride using prime if the petcocks are working right because when you run out of gas, you'll be out....

[mmaddix]

PRIME allows fuel to flow to carbs when the engine is not running, no vacuum required, it also eliminates any reserve, so when you run dry in PRIME, your dry and walking.

ON requires vacuum to allow fuel to run to the carbs, and keeps the reserve function intact. When you run dry in ON turn it to RESERVE and you have some fuel left to get to the service station. RESERVE also requires vacuum from the running engine to allow fuel to flow to the carbs.

That makes sense. How much fuel is left for the reserve? The standard tanks are 5.3 gallons right so is 4.3 for normal use and 1 gallon left for reserve or how does that work?

[mmaddix]

Set your petcocks to 'on'. This will draw fuel down until there's about 1/2 gallon left, when you'll want to go to 'reserve'. The 'prime' function is there so if you run completely out of fuel and the motor won't start, you can fill the carbs manually. Both reserve and prime draw from the same level, so you don't want to ride using prime if the petcocks are working right because when you run out of gas, you'll be out....

Thank you. You answered my question as I was typing it I guess.

[cywelchjr]

Thank you. You answered my question as I was typing it I guess.

The standard tank when it hits reserve with the stock peacocks on it has 1.1 gallons left (approx) giving you around 30 to 40 miles till dry. This is unlike the special which has about 1/2 gallon left when you switch to reserve. Also least on MY standard peacocks only one fitting points in, the other points forward and is the vacuum fitting. Makes it easy, gas fitting faces in, vacuum faces forward toward the engine.

You have to forgive any spelling errors in may make today, and I'm under the influence of good painkillers and my new android tablets auto spelling get correction.

[fredintoon]

No matter which style of gas tap you have and if you have converted to manual tap operation or not;there's another thing to worry about, or at least, to check on.
The main to reserve function is controlled by the filter tower atop the gas tap inside the tank.
Those little plastic bastards can fall out of the tap and lay in the bottom of the tank.
They can be like that for years because it is a symptomless problem.
You won't know about it until you find the need to switch to reserve and find it's already gone.
OK, so long as you watch the odometer/red light/gas gauge you'll still be OK,
but you are still running on unfiltered gas, right?
I've no idea how many of the filter towers fall out, I just know that mine did.
Luckily, I always carry a 2 gallon jerrycan of gas on the rig when I ride out of town, so my experience wasn't traumatic at all but you solo guys should check the filters now and again.

[crazy steve]

Fred, I don't think that's a problem with the standard petcocks; I know the early ones have the filter riveted to the petcock body, so it can't fall out. I think that's true of the later ones too. Yes, the Specials have them just pressed it, so those you should check.

[XS1100_OEM4ME]

Tops and bottoms

Tops and bottoms are pressed in on Specials, the tops pop off all the time as they get older. You can use tester model glue, the good sniffing kind, on the tops, as it melts the plastic togather so gas wont effect it, or you can melt / wield the plastic togather with a sodiering iron. The bottoms can be fixed with a stick of gas tank repair (the stick of pitty like stuff that is black on the outside and white in the middle, just cut off a 1/2" piece and mix it then fill the grove in the petcock with a bead and press the filter back all the way

Fred, I don't think that's a problem with the standard petcocks; I know the early ones have the filter riveted to the petcock body, so it can't fall out. I think that's true of the later ones too. Yes, the Specials have them just pressed it, so those you should check.