Only half of my tank?

[SirBlueKoala]

Hey guys I just recently bought a '91 GS500E couple weeks back(also new to riding).
Mainly the problem is that my tank holds 4gallons, but only uses about half. Not exactly half but i get about 70-80miles before i "run out," but when i open my cap i can clearly see that there is atleast half left in the tank. If anyone knows what is wrong with it or what this phenomenon is please leave a reply. If not i'll just take it to a shop which i will most likely have to. Thanks.
p.s. im idling at 2k is that ok?

[Wrider]

When you open the tank, does it hiss? A lot of times there's a small problem with the gas tank vent not letting in enough air. Pretty easily fixed.
Do you know how to turn the petcock to "reserve"?

[SirBlueKoala]

It doesn't hiss. So i should just put it on reserve?

[Wrider]

Definitely. If it doesn't help, there is probably a clogged fuel filter somewhere. If it does, you have 2 options. 1. You can leave it be and switch to reserve as needed. Or 2. You can get someone to pull the petcock and trim the regular hose down a little. There are two hoses in there, one for regular, one for reserve. The regular is longer so that it will stick out of the fuel earlier, cueing you to switch to reserve and letting you know that it's time to refuel. Trim it down a little (but not too much) and it should help.

[SirBlueKoala]

Alright i will try both and hopefully option 1 works, will there be any downside for leaving it on reserve?

[Wrider]

Other than possibly running out? Not a one.

[JackoftheGreen]

Don't wanna hijack the thread, but is that all there is to On and Reserve? Just a longer hose? The OM for PowerSlave makes a big deal about switching the petcock to On before filling the tank, stating that if you accidentally fill up while it's on Reserve you may not actually have a full tank. I've always assumed there was some kind of wall inside.

[Wrider]

Nah that's all it is in 9/10s of cases. At least every one I've ever seen.

[Boris]

Hope I'm not wasting any threads just want to let you know I've never heard that you get less petrol when you fill the tank up when the tap is on reserve. As this ain't a 2 stroke bike I found out that the tap works slightly different depending on models, not like all the smaller bikes. When you have your petrol on, done your journey what we normally do is turn the petrol tap horizontal for it to be off and down for main tank and straight up for reserve, but I found out about 3 years ago that the bigger bikes don't know which ones exactly, the off position is for priming so will pour out quicker than if it was in the main tank or reserve switch so if you find you turn your petrol off at night and try to start it in the morning and the engine is flooded on the first try you'll just have to leave your petrol in the on position overnight you just have to remember there is no off switch but there is down for main tank and up for reserve and you can't go wrong until you need reserve, horizontally the off switch has become redundant but your bike will be much easier to start in the mornings this I learned the same day I moved from a 125cc to a 600cc bike something I never learned in my 22 years of riding I hope this advice will be of some help in the future for you Happy riding and be safe and be seen

[SirBlueKoala]

Thanks everyone for the help. After 80+ miles i set it to reserve and it seems to be doing the trick im going about 140+ miles now.