Something funny with my reserve...

JAK1981 · August 21, 2006, 11:10:11 AM

A couple weeks ago I ran out of gas completely. I have a 90' GS500. I was running on "Fuel" for quite some time, waiting for it to start cutting out so that I could experience what it's like to switch to reserve while on the road.

Well, it started losing power and switching to reserve did nothing. I got to the gas station and put in 14L. I have a 17 L tank I think. So it seemed that I had 3L left that I could not access.

So I thought this could mean that the reserve line is clogged. But, after I filled the bike up, I could run on the reserve setting. And also, there was 3L left in that tank when I "ran out".

So I ran on reserve after that fill-up and what do ya know, after 10L of consumption I had to switch it to the "fuel" setting. Looks like my reserve has somehow moved from the correct location inside the tank. Is this possible? Does anyone know how I can fix this? Is it just a matter of moving it to the right spot again?

Egaeus · August 21, 2006, 11:12:06 AM

SOmewhere your fuel lines got switched.

JAK1981 · August 21, 2006, 11:17:10 AM

Well, I thought that, but if I run the bike on the reserve setting, the bike needs to be switch to fuel to keep running when there is still 7 Leters left in it. Also, when it's on the fuel setting, it can only burn 14L. Is the tank not 17L on the 90' GS500? How do you explain that one?

And thanks for you help too!

Egaeus · August 21, 2006, 11:25:11 AM

The tank capacity is its total internal volume. That includes the parts above the filler neck that contain air and the parts below the reserve intake that can never drain out of the tank.

In other words, the usable volume is considerably less than its stated capacity.

Wrecent_Wryder · August 21, 2006, 11:28:48 AM

There's no real "fuel" setting, so that makes it hard to interpret your post- the settinga are "on", "reserve", and "prime". The word "fuel" is just to label the whole valve.

But, Egaeus is quite right, there's a lot of virtually unusable capacity.

JAK1981 · August 21, 2006, 11:35:24 AM

Oh ok I see. So it looks like my total usable is is about 14L then. About 3.5 GAL. Does that sound right?

Egaeus · August 21, 2006, 11:40:44 AM

I got about 3.9 gallons in mine when I ran it almost dry (switched my fuel lines), and it was hurting for gas. I filled it as full as I could.

Wrecent_Wryder · August 21, 2006, 11:44:04 AM

Probably fairly close.

I have a 2002 with the larger tank, and was alarmed when I hit "reserve" for the first time at only 168 miles. I found that it varies a great deal by how much time I'm willing to spend filling it up. The fuel sort of "settles" over time, and if I spend enough time, I can get quite a bit more in.

Unfortunately, I also found that if I fill it a little too far, fuel will pour out of the overflow tube onto the ground when I raise the bike off the stand... probably not worth the effort.

scottpA_GS · August 21, 2006, 11:53:15 AM

Also there is a small plastic tube w/ screen that make (RES) possible. On my bike I removed it thus eliminating (RES) the lines are still there and still the same but the abbillity to use (RES) is gone

Maybee that is the case on you bike

MarkusN · August 21, 2006, 02:29:10 PM

We just had the same case on the German board. You probably are misinterpreting petcock settings.

Lever straight down is ON
Lever to the left / front is RES
Lever straight up is PRI

As others have stated: there is no FUEL setting.

When you thought you were running on FUEL, you were probably running on RES.

FearedGS500 · August 21, 2006, 04:37:52 PM

might want to let us know what year it is to

might help a little on the 05's its (clockwise starting from the top ) res,pri,on

TragicImage · August 21, 2006, 04:53:44 PM

Quote from: FearedGS500 on August 21, 2006, 04:37:52 PM
might want to let us know what year it is to might help a little on the 05's its (clockwise starting from the top ) res,pri,on

uhm. he said it was a 1990

JAK1981 · August 23, 2006, 07:00:13 AM

Quote from: scottpA_GS on August 21, 2006, 11:53:15 AM
Also there is a small plastic tube w/ screen that make (RES) possible. On my bike I removed it thus eliminating (RES) the lines are still there and still the same but the abbillity to use (RES) is gone

Maybee that is the case on you bike

Hey thanks for the suggestion but I can run on reserve if I'm full. So this means that the lines are working.

JAK1981 · August 23, 2006, 07:02:35 AM

Ok, sorry for the misunderstanding. When I said FUEL, I mean on. And I've always known that ON is Streight down. Sorry for the confusion.

I think the verdict is that my ON and RESERVE are switched, and like most other people I can only actually use 3.5 > 3.9 gallons at the most...

Sound right? Should I forget about this now?

MarkusN · August 23, 2006, 07:52:21 AM

If it's just RES and ON hoses switched and you don't want to correct this you can just switch petcock settings as well: RES for ON, ON, for RES. You can't PRIme, though, once you've run into RES domain, so that's probably not what you wnat to do. Switch hoses.

There are also other hose swap scenarios that can have the effect you describe (in and out hoses of the petcock switched.)

JAK1981 · August 23, 2006, 08:14:03 AM

^^^Very good. I think I'm gonna get my self a good repair manual. Unless I can find some diagrams....

Thanks a lot for your help. (thumbs up)

MarkusN · August 23, 2006, 08:21:11 AM

Oh yeah, diagram. Nobody posted this yet?

JAK1981 · August 23, 2006, 08:56:30 AM

Ok that was very helpful. So the carbs create a vacume to suck the fuel, and with the petcock switch, you can direct the vacume to either the RES line or the ON line.

So how does Prime work then? A can guess that it allows both lines to feed the fuel?

I'm trying to think of all the arrangements and their causes. If the line to the carbs was in the wrong place, you could then shut off the fuel by either RES or ON....correct? And thanks for the help

JAK1981 · August 23, 2006, 09:05:56 AM

Oh nice, look what I found http://www.gstwin.com/fuel_hose_routing.htm

MarkusN · August 23, 2006, 10:54:52 AM

That's not quite how it works. The petcock is a vacuum operated valve, you got that right. However, vacuum opens both the RES an ON inlet at the same time. The chicken then selects which inlet is routed to the OUTLET nipple. PRI is a third inlet that bypasses the vacuum diphragm and is always open. When the chicken selects this one there is fuel flow regardless of the presence of vacuum. (I may have that reversed, in fact quite probably; I think the vacuum operated valve is on the OUTLET side.)

As for other posible scenarios: If you switch ON and OUTLET hoses, the chicken works (even though in reverse) when set to ON. Switching to RES or PRI will just short them to the ON hose, so no flow. Similar things happen when you switch RES and OUTLET.

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Something funny with my reserve...