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Hello!

I've got Suzuky GS 500F (without user manual) and I am totally confused about how the reserve tank operates.
Could somebody help me to sort that out?
The switch has 3 positions - reserve, on and PRI.
Which should be switched on while tanking to make sure that the reserve tank is filled up? And in which position it should stay to prevent the reserve tank from being used on the ride?
I've already run out of fuel a couple of times and it seems I can not figure out what I should do with the switch
Thanks in advance

There is no reserve tank per say. Your fuel valve has two feeder tubes to get gasoline from your gas tank. One is higher than the other and is reached first this is where the valve gets fuel in the On position. Once fuel levels drop to or below this level you can't get fuel to your engine in the on position.

The lower feeder tube is accessed when the valve is in the reserve (res) position. Once you switch you have about a gallon to a gallon and a half to find a gas station. Once you fill up remember to turn it back to ON so you don't run through your reserve without knowing it.

Sometimes you've either run the fuel out of the carbs because you didn't switch to reserve soon enough or you put your bike up for the winter. Pri stands for prime which allows fuel to run directly from the tank to your carbs.

In the other two positions the valve only lets gas flow when the engine is turning, which is accomplished by the vacuum generated by the engine. Thus it's ideal to leave the bike in either On or Reserve when it's not running. Otherwise fuel might flow into the carbs, overflow and head straight to your crankcase if your carb floats aren't set correctly or if there is junk in the carbs to keep them from sealing properly. This results in an oil change, more gas and a waste of time.

Any position is fine while filling tank. There is no separate "reserve" tank, per se. The bottom of your tank has two tubes inside, one of which is flush with the bottom, and the othe of which extends upward some small distance, maybe an inch or so.

When your petcock is in "PRI" position, gas is fed to the motor from the taller tube. When the gas level in the tank goes below the level of the taller tube, the motor will sputter, and soon die. Switching the petcock to "reserve" position allows gas to be fed from the lower tube (bottom of the tank).

Old (pre-1963, I believe)air-cooled VW's used the same system, not having a gas guage.

Switch your petcock to "off" when parked for any length of time. For normal riding, use "PRI". Learn to switch to "reserve" while riding, in the event that you get low enough to require it, and remember to switch back to "PRI" when you next fill up.

Hope this explains.

storysunfolding:

GMTA!

gliderider wrote:storysunfolding:

GMTA!

I have no idea what that means.

storysunfolding wrote:

gliderider wrote:storysunfolding:

GMTA!

I have no idea what that means.

Great Minds Think ALike.

No reserve tank - yet another revelation. I did think that they are physically separated
Must get the manual ASAP. Thanks a lot!

Bikes are usually simple and highly functional. The On/Res of the tank is a great example, providing you with just enough info to tell you to get to a gas station. Ingenious, really, providing high reliability, a minimum of parts, complexity and weight. Bikes though require you to understand more about the mechanics of your vehicle, unlike your cage.

On most bikes, farkled cruisers excepted, there is no unnecessary equipment on the bike. Look at your bike and think about removing any piece of equipment and you'll soon notice you really can't.

Choppers historically "chop"ped off turn signals, fenders, and anything else they could that did not directly affect the way the bike rides. You can get pretty extreme with being minimal.

Bikes maximize utility and efficiency. Today there are exceptions, such as scooters having cup holders, and Goldwings having microwave ovens. To each his ride.

You might also want to shine a flashlight into the fuel tank when it's nearly empty, and get a good look at what they are describing.

I recently found out "the hard way" that my main fuel pick-up tube had worked it's way loose, and was just lying in the bottom of my fuel tank.

I knew I was low on fuel and needed to fill up soon, but hadn't hit reserve yet. I had planned to use the reserve until I got to my destination, even though there were gas stations along the way.

As I'm riding, the bike starts to sputter and die, so I switch over to reserve. Surprisingly, the bike *continues* to sputter and die, and I coast to a stop along side the road. After trying to start it for a while, and wondering why the reserve wasn't working, I looked into the tank... BONE DRY!!!

With the main pick-up tube loose and lying in the bottom of the tank, the bike had been pulling fuel directly from the bottom of the tank, completely bypassing the reserve.

Luckily, I was only a 1/2 mile from a small town with a gas station, didn't have to push the bike very far. I'm also thankful it was fairly flat ground, with a decent shoulder.

So the moral of the story is:

You might want to make sure your reserve setting works before you have to rely on it!

TorontoBoy wrote:Bikes are usually simple and highly functional. The On/Res of the tank is a great example, providing you with just enough info to tell you to get to a gas station. Ingenious, really, providing high reliability, a minimum of parts, complexity and weight. Bikes though require you to understand more about the mechanics of your vehicle, unlike your cage.

Too bad the new fuel injected bikes just have a low fuel idiot light instead of a petcock.