Only 60 miles per tank?

[Clumzi]

When the bike was running, it routinely got 45 miles per gallon, what I've been told is about average for an old 550 like mine, but it would only get about 60 to 70 miles on a tank before needing to be refilled. When I just removed my gas tank, which I thought would be empty because of the stuck valve and all my gas leaking out of my carbs, there was still a good amount of fuel left in the tank even though the bike "ran out of gas". Any idea why all the gas isn't being drawn from the tank? -nick

[BassCliff]

Is something blocking a fuel line? Is the mesh on the top of the petcock covered in mush? Is there a vacuum issue? Have you tried setting the petcock on PRIme?


Thank you for your indulgence,

BassCliff

[jmanz6]

Had you switched to "reserve" on the petcock? The gas tank doesn't go completely empty when in the "on" position. There is some left for reserve so you can get to a gas station. 60 miles per tank is really bad. You are running pig rich if you aren't leaking it out between runs.

[Clumzi]

It's weird as hell, right? The petcock is oem vacuum petcock, it is the one that you have to adjust with a screw that you aren't supposed to fiddle with. There is no reserve tank setting, ie no reserve tank. Just prime and on. The gas gauge works and it hits the red line around 75 miles and starts to loose a bit of power around 65 miles. The tank only takes 1.5 gallons.



-nick

BTW - Basscliff, the petcock was rebuilt not long ago by a real good mechanic, all the lines are fine and this was happening before the petcock rebuild. I can't necessarily speak to a vacuum issue, but wouldn't that kill the mpg? The mpg is good, 45 mpg like clockwork, sometimes better. You aren't supposed to run it on PRI, right?

[rphillips]

Sounds like bottom 1/2 of screen in tank is clogged. Vac petcock shouldn't work for the first 1/2 tank then close, nor should a blocked fuel line be open for the first 1/2 then be stopped up. Just my opinion

[Riding Again]

Late to the thread and very little research with clumzi's posts.

Don't remember if he's gone through the carbs? After spending the downtime this summer replacing the head gasket, I took the time to do the carbs. A 24-hr swim in a private pool for each carb, an invigorating blow dry, and freshly dressed with new o-rings. Enjoyed the short time they were back together.

While slabbing it home one day I had to pull over as the engine died !

Found NO gas in the carbs. Primed it by pulling a vacuum, couldn't get it to flow otherwise and I can't imagine what it looked like to passerby's as I was priming the carbs again .

I digress, what I found was not a stuck float, but a stuck valve upon disassembly (all carbs out again and into the spa)

Go through the carbs again.

[Clumzi]

I digress, what I found was not a stuck float, but a stuck valve upon disassembly (all carbs out again and into the spa)

Go through the carbs again.

Lol, this looks like a post for my carb issue. I'm hoping that is why my bike decided to pour out all the gas that was in it, a stuck valve.

I'm starting to wonder if twenty year old motorcycles actually ever run or if seeing them running is just a trick of the eye -nick

[twr1776]

Have you checked the petcock filter? If it is the original petcock you might want to replace it. I am no carb expert but if it is the original to the bike it should be replaced IMHO.

[TheCafeKid]

1.5 gallon tank? well, if you're getting 45MPG which is a lil low for that bike IMO, but we'll take it at the moment, and the tank holds 1.5 gallons, 65-70 miles IS all you're going to get out of it. MOST bikes wont get that last 1/4 gallon or so out of it before you start sucking air, so from MY perspective, I think you're probably doing ok...

[Clumzi]

lol, I might be a history teacher, but my math skills aren't that bad . The info I have says the tank is supposed to be about a 3 or so gallon tank, so I guess the real question is why is it only taking 1.5 gallons? Is the gas sloshing around in there 1.5 gallons that it isn't using?

I hear what you folks are saying about the petcock filter, but the gas gauge is reading empty, which also implies to me that the extra gas sloshing around in there can't be another 1.5 gallons. Could something be physically stuck in the tank? I suppose I could poke a stick in there and find out. -nick

[shadowfist]

did someone stick a 1.5 gallon marble in the gas tank?

[rphillips]

You've got the tank off, pour the gas into a pan or bucket to see how much is still in there. With the "80" petcock, when you run out of gas, the tank should be empty. There is none left for res. as the "80" models don't have res. Don't rely on the GS fuel guages, I've seen very few that were accurate. Removal of petcock is a 5 min. job, pull it & check the screen.

[Riding Again]

Good idea on the petcock. After the stall I wrote about before, I forgot to add that I also installed a new petcock.

I took apart the old and found quite a bit of black gunk in the small passage ways. Now I've got a spare.