GS's never asks for RES?

[karneck]

First of all, excuse my poor and bad english, I'm brazilian and know very litle english grammar.
Please help me with my problem, I would be very thankfull.

I bought recently (2 weeks ago), a gs500e, year 1999, with 67000 km. The bike was very conserved, but as I recall reading in one of the many gs500e sites on the net, my bike presented that problem with the fuel-valve, (or something like that, i don't know what exactly word is the right one here...    ), wich is the folowing:
You fill the tank right to the top (17 liters) and rides with the bike until it dries...but the problem is that the tank doesn't get dry...the bike stops running, I open the tank-hatch, I see some fuel that looks like it can be something like 3 or 4 lts. still in there, but the bike doesn't start at all, not with the fuel-valve in the ON position, neither with it in the RES position. Then I took it to the place where I bought it (a motorcycles shop) and the mecanic there told me it's a problem every GS has and there's nothing I can do about it. It's a problem every GS500e has that it can't suck the fuel to the carburators strong enough when the fuel level is low in the tank. But I remember seeing some site that theres something we (gs owners) can do...please help me, I would really aprecciate it. I'm sorry again for the poor english...I hope I could describe the problem well so u could understand it. Please help me -asap-. U guys here are my only hope. Any and all advice will be greatly appreciated.

[Kerry]

Unless you replace the ON/RES/PRI petcock with a different solution, you really only have one choice: When the fuel stops flowing in the RES position, turn the switch to the PRI position.

With this method I have gotten my 1996 and 1999 GS500Es down to 1 and 2 tenths of a gallon, respectively - after stopping on the side of the road a few times and leaning the bike to the left to get more fuel to drain out of the tank.

With the fuel selector in the ON and RES(erve) positions, fuel will only flow to the carburetors when the engine is running, due to vacuum pressure.  I suppose the height of the fuel in the tank exerts additional pressure that helps open the diaphragm in the petcock.

With the fuel selector in the PRI(me) position, fuel will flow to the carburetors whether the engine is running or not, due to gravity alone.  Presumably, this setting bypasses the diaphragm normally operated by vacuum line pressure.

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You CAN try other fuel system configurations.

One idea is to run a fuel line directly from the RES (forward) outlet on the fuel tank to the lower 'T'-fitting between the carburetors.  (You would need to cap off the ON outlet, and possibly the vacuum line from the left carburetor.)

A related idea is to connect a single-in, single-out fuel switch along the length of the single fuel line mentioned above.

However, GS owners usually resort to these 2 ideas because of an insufficient RATE of fuel flow, not necessarily to drain the fuel in the tank to a lower level.

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GOOD LUCK!

[karneck]

Thanks a bunch Kerry, u almost killed my problem, but there's still just one doubt in my mind...the reason I exposed my problem here, is because it happened to me as follows (this part I didn't explained):

I filled the tank to full (about 17 lts) and drove with it a lot. Then, in the midle of a avenue, the throtle begins to ignore my commands, not giving me any response...here I assumed the bike was asking for the RESERVE, then I turned the fuel petcock to the RES(erve) position and nothing happened! (maybe I was unpacient, and didn't wait long enough, but the fuel didn't seem to be flowing, this with the engine running!...slowing down but running), then I turned the fuel petcock back to ON position and then the bike really stoped and couldn't start again. So, according to your knowledge of this problem, what I should've done here was to first turn the engine off, turn the fuel petcock to PRIME position for about 30 seconds, put it back on to RES(erve) position, and try to start the bike (because what probably hapenned was that the carburators went out of fuel). If I did this, I would be able to burn the reserve amount of fuel in the tank. Right?!

[chimivee]

So, according to your knowledge of this problem, what I should've done here was to first turn the engine off, turn the fuel petcock to PRIME position for about 30 seconds, put it back on to RES(erve) position, and try to start the bike (because what probably hapenned was that the carburators went out of fuel). If I did this, I would be able to burn the reserve amount of fuel in the tank. Right?!

Right!  (Kerry knows!)  It seems that if you don't switch to RES quick enough the fuel level in the carbs can get too low and it is difficult/slow to get fuel flowing again in RES.  Switching to PRI for a few seconds fills the bowls back up quickly w/ fuel so that it flows again under RES.  Unfortunately, at this point you may already be on the side of the road.

I'm trying to get in the habit of switching immediately to PRI instead of RES once I start to run out of gas in ON.  This hopefully fills the carbs back up w/ fuel before the level gets too low so I can still be keeping up with 75mph traffic on the freeway.  After a few seconds I can then go to RES... or more likely just leave it and get to the stinking gas station.

[karneck]

Allright! Thanks James...for now.

[karneck]

[JamesG]

I think you have a bad fuel selector or a vacuum leak.  The one in my GS started doing the same thing you describe. Loss of power and dies even when there is fuel in the tank.
My theory is that either the rubber diaphram hardens or wears out; or it starts to leak vacuum somewhere and the ruduced pressure from a less than full tank can't keep the diaphram open so the carbs starve for fuel.  
I fixed it by taking the fuel selector body apart and cleaning the diaphram and after putting to back together, smearing RTV all the way around the sides to seal it.

[chimivee]

So, did you try starting/running the bike in PRI?  Once you start losing fuel, switch to DIRECTLY TO PRI - forget RES.  Leave the chocke off.  Ride for about a minute in PRI, THEN SWITCH TO RES.  See if that works.

If that works, then it could be, as previously mentioned, that the carbs were too low on fuel.  You may want to check your float height... maybe they're too high, so once you start running out of gas, it quickly drains the bowls, requiring PRI to get going again...   :dunno:

If it runs in PRI, but upon swithching back to RES it sputters out again, then JamesG is probably right about a vacuum leak/pressure loss.  You could try and fix as described... or just run in PRI until you fill up next.

[Casimir]

It could be a pinched or blocked reserve fuel line. I know when I took my tank off, it was difficult to get everything back in the right place..

There is a decent picture here to show you the correct routing.

Also, since the reserve draws from lower in the tank, it could be that its screen is gummed up if it was left sitting with a small amount of gas in the tank.

You may want to read this and this discussion for more ideas.

Personally, I use the trip odometer and just refill at around 170 miles. I always fill the tank so that works fine and I don't have to use reserve at all. Of course, I generally ride for pleasure only and can choose the length and route of my rides.

[werase643]

I have this really kewl device to keep me from runing out of fuel....
it's called a TRIP METER.....I had it designed into a special speedo by the SUZUKI engineers.  When the trip meter indicates....150 miles.....I fill up the tank.  I have never run out, yet!!!!
Just because you run your bike out of fuel.....doesn't indicate a problem with the design of the fuel system......

[Casimir]

Ahh, just thought of something else. If the fuel lines are reversed, you will run out with the petcock on "ON". You will have some fuel in the tank but it should be less than a liter.

Can you run on REServe with the tank full?
Can you run on PRIme when you have run out on ON? It shouldn't hurt to run with the switch on PRIme, it is just not a good idea to park it that way because a leak will drain your tank.

Also, I want to be clear on the problem. (This is probably just a misunderstanding in the translation.) You have said that the bike does not "ask" for REServe. Are you expecting an indicator light to tell you that your fuel is low? There is no such light, you know when you are running out of fuel when the engine stops. (Your English is much better than my (non existant) Portugese.  )

[Kerry]

I think Casimir has nailed it - it sounds like your fuel lines are reversed.  The hose that attaches to the bottom of the frame-mounted petcock should be attached to the LONGER outlet on the tank-mounted petcock.

If they are switched then you will experience exactly what you've been describing.

[karneck]

[karneck]

Ahh, just thought of something else. If the fuel lines are reversed, you will run out with the petcock on "ON". You will have some fuel in the tank but it should be less than a liter.

Can you run on REServe with the tank full?
Can you run on PRIme when you have run out on ON? It shouldn't hurt to run with the switch on PRIme, it is just not a good idea to park it that way because a leak will drain your tank.

Also, I want to be clear on the problem. (This is probably just a misunderstanding in the translation.) You have said that the bike does not "ask" for REServe. Are you expecting an indicator light to tell you that your fuel is low? There is no such light, you know when you are running out of fuel when the engine stops. (Your English is much better than my (non existant) Portugese.  )

Yes I can run on RES with the tank full, shouldn't I?
The second question: I'll sure try that!
And No, I'm not expecting any sort of light to turn on to alert me. By saying that, I just meant that the bike APPEARS (not sure about that) to burn the RES amount of fuel (3.5lts or so), without asking me to put the petcock to RES position, as your theory of the reversed fuel lines "embases" (does that word exists?   ).

[karneck]

Thank you all for the quick responses.
Considering all the responses, I personally feel that what's happening to me is 1 out of 3:
-the fuel lines are reversed, this way the bike consumes the reserve 3.5 lts without stopping.
-my bike has, as Casimir described: "a pinched or blocked reserve fuel line."
-or it may have, yet as Casimir described: "it could be that its screen (the reserve one) is gummed up if it was left sitting with a small amount of gas in the tank".
Also, one big problem here is that, as a Rookie in GS's, I can't tell how much gas exactly is still in the tank when I start running out of fuel just by taking a look...but it looks very much like less than 1 litter.
Or, of course, it could be NOTHING, and If do just as chimevee tells me to, I'll work it all out. I'll try all that this upcoming week, and then we'll see what's really going on.

[chimivee]

...but it looks very much like less than 1 litter.

Did you mean to say that it looks like more than 1 liter?  Because I thought you had said previously that it looked like 3-4 liters (which is consistant w/ the RES capacity)?

Assuming your carbs are in good order, it should be fine to run the bike in PRI.  In ON or RES, the fuel is sucked into the carbs under vacuum pressure w/ the engine on.  In PRI, the fuel does not require that pressure and is fed via gravity.

The float height determines the fuel level in the carbs.  I recall that if a float should get stuck, gas could "overflow" in PRI mode.  Or if the bike was on its side, perhaps gas would leak?  But otherwise, running in PRI should be okay - there are aftermarket petcocks that feed gas in the same way.

Ya know, going back to your original post, I think your mechanic may be partially right about this being "normal," or at least a common problem, on the GS.  One of the above links someone posted goes to one of my threads asking about the same thing.  After trying several suggestions I never really sorted it out.  Check out the other suggestions first, of course, but it may just be something to get used to...

[karneck]

Did you mean to say that it looks like more than 1 liter?  Because I thought you had said previously that it looked like 3-4 liters (which is consistant w/ the RES capacity)?

I know I disagreed with what I said before, but I think I was wrong before...today, it looked like LESS than 1 lt. And u bet I'm gonna try all the suggestions first.

[chimivee]

I know I disagreed with what I said before, but I think I was wrong before...today, it looked like LESS than 1 lt. And u bet I'm gonna try all the suggestions first.

OK, well, if the bike runs in the ON position w/ less than 3 litres in the tank, then I would think Casimir is right, the fuel lines MUST be crossed, since it should normally be cutting out around there forcing you to go to RES....yeah?

[karneck]

Well, it took a long time, but finally here's what it was all about: the fuel lines were crossed, so when the fuel petcock was in ON, in fact (with the fuel lines inverted) the carburators were already getting fuel from the RES instead...
Thanks u all that helped me.

[hehehemann]

The lines are crossed thereby making the bike run as if it's set to reserve all the time.  Other than not having a reserve tank when you run out of gas does this hurt the bike?