1993 Suzuki GS500E fuel economy... Help?

B

barkingsquirrel

Active member
Hey guys,

So I'm a newbie rider and recently I purchased a Suzuki GS500E, and have been having trouble understanding what's going on with my fuel economy. From what I've looked up, my bike should have a 17L tank with 3.5L reserve. That should equal around 200km/full tank...

Lately I have been finding that my bike will "lose power" and "die" around the 110km mark, and begin running again fine after I fill up. My only issue is this - when I look in the tank, it still looks about half full. I shake the bike and hear sloshing... When I fill up, it only takes about 9 litres to fill it up completely.

Is my bike just like that? Or is there an underlying issue that could be causing this?

Thanks guys.
 
There's definitely a problem, as you're clearly only using half the tank. Your bike is not supposed to be like that. It's kinda strange, though... I know older GS500s can have weird petcock issues, but I wouldn't expect that to cause what you're describing.

Does your bike run well otherwise?
 
Dumb question, but I assume that you tried switching to reserve?

My bike came with an aftermarket petcock that has taller straws than the stock one, so I hit reserve a lot earlier than I'm supposed to. I guesstimate that I have a 7.5L "reserve" right now. It confused me the first time I hit reserve after a mere 150 kilometers.
 
I used to have same bike... Your reserve is good for. 50 km

So if you get 100 then die out meaning you go to reserve and get another 50 more

Thats 150 total. But still short,,

Has the carbs been rejetted? Its a common gs500 upgrade

Or have the sprockets been changed ?

These two affect mileage

Also some gs500 get fuel starved when tank gets lower. Because its gravity fed. You need to see if your gas tank vent is ok and you need to make sure your gas filter is ok. And you need to make sure your fuel lines are routed correct...



"If i was educated, I'd be a damn fool"
 
Do you have a fuel filter in the line?

I'm wondering if there is resistance in the lines somewhere. Maybe the pressure from a full tank is enough to run normally but only 1/2 tank and fuel pressure drops. Just a though.
 
Matt Rain said:
Dumb question, but I assume that you tried switching to reserve?

My bike came with an aftermarket petcock that has taller straws than the stock one, so I hit reserve a lot earlier than I'm supposed to. I guesstimate that I have a 7.5L "reserve" right now. It confused me the first time I hit reserve after a mere 150 kilometers.
Click to expand...

This is a good point, it could easily already have an aftermarket petcock on it
 
TwistedKestrel said:
This is a good point, it could easily already have an aftermarket petcock on it
Click to expand...

There is no telling what previous owners have done to it. My GS500 was only an 06. I thought the forks were a little soft, especially for my weight, so I ordered some new springs. When they arrived I took the fork's apart to throw them in and this is what I found:

springs.jpg
 
The bike runs great otherwise... I haven't had any other issues with the bike, this is the only one that has come to light thus far, and I've been riding it for a few weeks.
 
Matt Rain said:
Dumb question, but I assume that you tried switching to reserve?

My bike came with an aftermarket petcock that has taller straws than the stock one, so I hit reserve a lot earlier than I'm supposed to. I guesstimate that I have a 7.5L "reserve" right now. It confused me the first time I hit reserve after a mere 150 kilometers.
Click to expand...

Yeah I switch to reserve after the bike starts getting jumpy and losing power and revs. I honestly wouldn't even be surprised if it's got an aftermarket petcock... It's just a little frustrating not knowing exactly how much my tank has in it, and I'm a little scared to run it dry to find out.

Another point I should probably add is that the bike has been sitting for nearly 3 years and it has had gas in the tank for most of it. I'm thinking maybe there's some crap built up thats clogging it and not allowing it to work to its full capacity? I've seafoamed it but it doesnt seem to have done much.
 
cbcanada said:
I used to have same bike... Your reserve is good for. 50 km

So if you get 100 then die out meaning you go to reserve and get another 50 more

Thats 150 total. But still short,,

Has the carbs been rejetted? Its a common gs500 upgrade

Or have the sprockets been changed ?

These two affect mileage

Also some gs500 get fuel starved when tank gets lower. Because its gravity fed. You need to see if your gas tank vent is ok and you need to make sure your gas filter is ok. And you need to make sure your fuel lines are routed correct...



"If i was educated, I'd be a damn fool"
Click to expand...

It's definitely short... I'm gonna have someone take a look at it and see if it has something to do with the carbs or sprockets... As I said, I'm a newbie so I don't know too much about it myself.

These are things to think about though.. Thank you!
 
Yeah Seafoam is not gonna do anything for ya, I've been there. Your pilot jets are very likely to be clogged, but that's not gonna cause a sudden loss of power.

I think you do have a taller petcock. Best thing you can do IMO is test how much of a reserve you have. MEC sells 1-litre fuel bottles, you can buy one or two, fill them up and carry them in a backpack while you ride the bike on reserve til it dies.

Sent from my iPhone using Tapatalk
 
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Dying after 9L is very curious. Some how it's getting starved, I'd suggest following cbcanada's idea about checking the fuel lines.

It isn't your fuel economy, even with rejetting, and an aftermarket exhaust and air filter, I can still do well over 300km on a tank. Somethings not right.

If you need a hand, just let me know.
 
tricky said:
Dying after 9L is very curious. Some how it's getting starved, I'd suggest following cbcanada's idea about checking the fuel lines.

It isn't your fuel economy, even with rejetting, and an aftermarket exhaust and air filter, I can still do well over 300km on a tank. Somethings not right.

If you need a hand, just let me know.
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Thank you! The friends I have suggested that there is an issue with my bike all tell me "oh your bike is just like that, its been sitting for years and just needs to be ridden to blast the gunk out of the engine", and then refuse to look at it and see if there's anything wrong, which there obviously is.

I'd appreciate the help to figure out what this is!
 
barkingsquirrel said:
Thank you! The friends I have suggested that there is an issue with my bike all tell me "oh your bike is just like that, its been sitting for years and just needs to be ridden to blast the gunk out of the engine", and then refuse to look at it and see if there's anything wrong, which there obviously is.

I'd appreciate the help to figure out what this is!
Click to expand...

Yep. I used to get 280-320 depending on the mix of highway/city driving I did. You should be getting around 250, definitely well over 200 before reserve. I would investigate:

Petcock (at tank)
Petcock (prime, reserve, main)
Fuel lines
Gas tank vent + hose
Fuel filter if you have one
If you still haven't found anything, check the carbs

That is everything between the gas sitting in your tank and the intake to the engine. Fuel line is pretty cheap, you could probably replace it all for $20. It might be worth doing anyway, because it gets brittle as it ages and is more prone to cracking, leaking, and breaking. Again mine was only a 2006 but I had the main line break on me as I was putting the tank back on one day. I had to pinch off the line and yell at my wife to come help me, but not before loosing 1/4 of a tank to the ground.

I would also be curious to know far you can get on reserve. It might be worth filling up a little container then running it right until empty.

Let us know if you find anything.
 
Hey guys! I've been working on getting this issue ironed out, and made a pretty interesting (and annoying) discovery yesterday.

I went for a really long ride yesterday with a can of fuel, just to see if I could empty my bike completely to see how many kms I get on a tank/reserve. I got to about 145km before my bike started sputtering and losing power, and I switched it to reserve. On reserve, I got to 215km, and it was still going. At that point I had to head to work, so I filled it up completely and it only took 13.5L, which meant I still had about another 3.5L left in my tank to go on.

Apparently my reserve/reserve straws are much bigger than originally thought, and my bike kicks into reserve way earlier than it needs to. I'm going to have a friend take a look inside to see if anything is out of the ordinary, but thought I'd report my findings if anyone cares. :)
 
Good stuff. Sounds like its in the right ballpark as far as fuel economy
 
barkingsquirrel said:
Hey guys! I've been working on getting this issue ironed out, and made a pretty interesting (and annoying) discovery yesterday.

I went for a really long ride yesterday with a can of fuel, just to see if I could empty my bike completely to see how many kms I get on a tank/reserve. I got to about 145km before my bike started sputtering and losing power, and I switched it to reserve. On reserve, I got to 215km, and it was still going. At that point I had to head to work, so I filled it up completely and it only took 13.5L, which meant I still had about another 3.5L left in my tank to go on.

Apparently my reserve/reserve straws are much bigger than originally thought, and my bike kicks into reserve way earlier than it needs to. I'm going to have a friend take a look inside to see if anything is out of the ordinary, but thought I'd report my findings if anyone cares. :)
Click to expand...
Awesome, sounds like you found the problem. I'd check out the petcock and the brass tubes inside the tank. I seem to remember one of mine sliding a bit when I pushed the fuel line onto it. Maybe it got pushed up into the tank? Not sure how possible/likely that is.

Sent from my Nexus 5 using Tapatalk
 
cbcanada said:
Are you sure your fuel lines are not crossed up on the petcock


"If i was educated, I'd be a damn fool"
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If they were, switching to "reserve" wouldn't do anything as they'd already be out of gas
 
barkingsquirrel said:
Hey guys! I've been working on getting this issue ironed out, and made a pretty interesting (and annoying) discovery yesterday.

I went for a really long ride yesterday with a can of fuel, just to see if I could empty my bike completely to see how many kms I get on a tank/reserve. I got to about 145km before my bike started sputtering and losing power, and I switched it to reserve. On reserve, I got to 215km, and it was still going. At that point I had to head to work, so I filled it up completely and it only took 13.5L, which meant I still had about another 3.5L left in my tank to go on.

Apparently my reserve/reserve straws are much bigger than originally thought, and my bike kicks into reserve way earlier than it needs to. I'm going to have a friend take a look inside to see if anything is out of the ordinary, but thought I'd report my findings if anyone cares. :)
Click to expand...

Hehe, I knew it. Exact same thing happened to me.

BTW I haven't bothered changing the petcock. Whatevs.
 
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