So today I embarassingly "broke down" on I-5 because I ran out of gas. I switch the petcock over to reserve, but I still wasn't able to get any fuel. The first day I got the bike, I ran out of gas when I was pulling into the garage at my place. I switched to reserve and was able to pull into my spot.

Do I need to do something special to refill the reserve? I checked the manual but it was rather vague.

not that not a normal question.  I would have to say there is not anything you can do but fill the tank all the way to refill the reserve.

I've fill the tank probably 10 times since I got the bike, and I always fill it to the brim. I haven't had a chance to check out the gas tank much, is there a chance that the flow to the reserve tank is blocked? That's all I can think of at this point, but I don't know how to check it.

There is no reserve "tank." The reserve tap just draws fuel from further down in the fuel tank. If you've got the tap set to On and you're still running out of fuel, check to make sure the hoses running to the petcock are the right way round.



Visual Aids!

What does this mean:

"I switch the petcock over to reserve, but I still wasn't able to get any fuel."

How do you know that? Do you mean that the bike wouldn't start? Or did you actually pull the fuel line off to check for fuel flow? I THINK you're telling us that you switched to reserve, but the engine wouldn't start; is that correct?

If you switched your fuel tank to reserve and the engine still wouldn't run, then you most likely have water (formed from normal condensation) in the bottom of the gas tank. Since gas is lighter than water, it floats on top of the condensation; when you run low on gas, the main fuel pickup tube is sticking up into nothing but air in the tank, and the reserve fuel pickup is sending water from the bottom of the tank to the carbs, which is why your engine won't start.

Drain your fuel tank; better yet, flush it after you drain it, so you can try to remove some of the crud from the crap pockets. Then refill the tank with FRESH gas, and set your petcock to ON; reserve should function properly after that until enough condensate water builds up in the bottom of the tank again. Draining and flushing the tank can help prevent rust from eating through the crap pockets, so if you've never done it before, no time like the present.

See the illustration above (thanks, Brembo!) for an idea on how the fuel pickup tubes work: the green line represents the amount of gas in the tank. When the fuel drops below the level of the main pickup tube, you have to switch the petcock to reserve; when that happens, you're drawing fluid from much closer to the bottom of the tank, where the condensation is. Oddly enough, you might still have some gas in the tank, but you can't get to it because it is floating on top of the condensation, and the reserve fuel pickup is sitting in water. If I had a nickel for every pint of water I've drained from fuel tanks over the years... I'd have a pretty big stack of nickels.

Thanks for the visuals brembo. I didn't really know what exactly reserve meant before.

Quote from: Cal Amari on February 19, 2006, 03:19:01 AM
What does this mean:

"I switch the petcock over to reserve, but I still wasn't able to get any fuel."

How do you know that? Do you mean that the bike wouldn't start? Or did you actually pull the fuel line off to check for fuel flow? I THINK you're telling us that you switched to reserve, but the engine wouldn't start; is that correct?

That's correct, I switched to reserve and the engine wouldn't start. This was all on the side of freeway, so I wasn't about to do extensive troubleshooting. (Honestly, nor do I believe I would have thought about it.) I have a feeling the lines are routed properly. I'll check the tank tomorrow when I've got a chance. I checked the main page and the FAQs for draining the tank, but found nothing. I've got the owners manual and a Clymer at home. Will either of these have a guide to draining the tank? If not, does anyone have advice or a link as to how to do it?

Edit: If even a small amount of condensation formed, wouldn't that prevent the reserve switch from working? Or would the engine effectively eat through the small amount of condesation and then move on to burning real fuel?

The simplest explanation has been overlooked.  If your bike quit running because you ran out of gas, then your carburetors need to be refilled.  Put the petcock on PRI for a minute, then try to start it.  If that doesn't fix it, then it very well could be water in the tank. 

Edit:  As far as fuel line routing goes, it's pretty simple.  There are two lines out of the gas tank, long and short.  Think of them as being the same length.  The long one is down lower, so it's your reserve.  The short one is higher, so it's your main supply. 

On the petcock of my 99, the reserve goes on the rear part that points down.  The main goes on the front part that isn't running to the carburetor.  The PRI(ME) setting draws fuel from the reserve line.

Quote from: Egaeus on February 19, 2006, 07:30:18 AM
The simplest explanation has been overlooked.  If your bike quit running because you ran out of gas, then your carburetors need to be refilled.  Put the petcock on PRI for a minute, then try to start it.  If that doesn't fix it, then it very well could be water in the tank. 

This is also what I think. You need to set the tap to prime, this will allow petrol to flow into the carbs without the engine running. You should them be able to start the bike. Now set the tap to reserve.

Quote from: ukchickenlover on February 19, 2006, 08:09:45 AM

Quote from: Egaeus on February 19, 2006, 07:30:18 AM
The simplest explanation has been overlooked.  If your bike quit running because you ran out of gas, then your carburetors need to be refilled.  Put the petcock on PRI for a minute, then try to start it.  If that doesn't fix it, then it very well could be water in the tank. 

This is also what I think. You need to set the tap to prime, this will allow petrol to flow into the carbs withoout the engine running. You should them be able to start the bike. Now set the tap to reserve.

Yeah. Last time I ran out of gas in the "on" position, I was on the freeway. I switched it to reserve and the bike just kept struggling to stay alive, so I switched to Pri and she roared back to life. I just left it on Pri until I parked.

Ditto CalAmari.

That is why aircraft have sumps to drain off moisture.
The newer bikes with vapor control are better protected than straight vents for condensation, but there is always the opportunity to pick up some bad gas.

When I don't hit reserve, I usually still flip over to reserve after leaving the station and getting up to speed so any minor moisture can feed through quickly.  If you get a slug and it completely cuts out, you can always switch back to main.
The bike has been sitting a while, especially outdoors, I'll run on reserve for a couple of minutes to clear condensation.

This also helps keep the valve slicked up.

Quote from: Thor S Magic Bathtub on February 19, 2006, 08:53:29 AM
Yeah. Last time I ran out of gas in the "on" position, I was on the freeway. I switched it to reserve and the bike just kept struggling to stay alive, so I switched to Pri and she roared back to life. I just left it on Pri until I parked.

I got very good at changing the petcock to PRI at freeway speed. It took a bit of practice, but it's a good skill to have; it saved my hide on one of our fastest freeways (280) many a time, since my '92 was blessed with a bad case of fuel starvation. 

Can i run always on reserve?
Where does PRI draw fuel from? Maybe from both ON and RES?

+1 on the comments that you probably just needed to switch to prime to refill the carbs.

Quote from: domas on February 19, 2006, 02:00:19 PM
Can i run always on reserve?
Where does PRI draw fuel from? Maybe from both ON and RES?

You can always run on reserve, but you're gonna get in trouble that way... you'll run out of gas and have nothing left.  Assuming everything in your fuel system is working correctly, always run on 'on'.  When you run out of gas, switch to 'res' for an extra gallon??  of gas to get you to that next gas station.  As mentioned above 'pri' refills the carbs when they are run dry, either running out of fuel or after servicing the bike.

Not exactly sure if 'pri' draws fuel from both or 'res' or what, but it works without vacuum like 'on' and 'res'... 'pri' works only on gravity.

My gf wanted me to put the afro guy in

I had plenty of time while waiting for gas (AAA - reliable eventually but sooooo slow), so I tried switching to PRI for a minute or two, but it still didn't work. I opened up the tank and saw some liquid at the bottom of it. After hearing your comments and thinking back on it now, it must have been water.

Also, if PRI draws from the reserve line and there is condensation, wouldn't that flood it with water and cause problems?

Pri setting draws from the reserve line only.  The difference is that the vacuum-operated diaphragm in the petcock is bypassed, so fuel flows whether the engine is running or not.  If there is water in tank it will be drawn through on either setting. 

Quote from: domas on February 19, 2006, 02:00:19 PM
Can i run always on reserve?

I used to use PRI when I was going to be doing high-speed, freeway riding for a while. If I was just tooling around town, I left the petcock on ON. And don't forget to turn it back from PRI to ON when you park it, or you could come back to a nasty surprise! (I love the afro emoticon, too!  )