Hi all,

First I apologize for any major faux pass I make, I am new here.

I am trying to nail down the most likely issue for why my '92 GS500E gets garage fuel economy. I burnt off about 10L of fuel in ~130km, died on the side of a highway, reserve didn't pull fuel, and there WAS still fuel in the tank, but minus the 10 L I filled in after pushing the bike.

I am assuming that I have some kind of clogged in the fuel chicken filter.. or some tank related chicken or filter or tube that should be in use when the fuel line is switched to reserve. I dont' think the clog would be in the fuel line itself, it runs fine when on a regular fuel setting.


However with regards to the consumption issue, I don't have the foggiest idea where to begin. The exhaust smells semi gas-y when running (sometimes) and there is sometimes a bit of a fuel smell when I sit atop the bike, stopped at a light/sign. However with that said, the garage does not smell of gas, so I don't suspect a leak allowing the fuel to off gas into the atmosphere.

The bike has a vance and hines 2 into 1 exhaust, the only part that isn't really stock on this bike. My understand is some carbs have to re-jetted when slapping on a new exhaust, but I don't exactly understand that either, the carbs deliver fuel to the cylinders, the exhaust exhausts.

Why would you have to up the fuel / air mix with new exhaust to make it 'run' properly. To me an exhaust just takes crap away from the cylinder (I am a bit of a lay person when it comes to vehicles).

Is it also possible that the fuel air mix is just... really rich?

Any help would be appreciated.

Intake and exhaust are related because they share the duty of moving air into and out of the motor. Bigger, more free flowing exhaust allows air to escape easier, thereby making it easier to pull more air in. More air in, with the same size jets, and now you have a lean condition.
However, it sounds like you are running way rich, so its likely that the PO jetted it way to big, or did something silly like drilling the jets out.
You will need to pull the carbs to determine what size jets are in there, and check the floats.
It sounds like you are not very experienced, no offence intended, as everyone has to start somewhere. Do you have a friend that rides and wrenches?
Try to read alot online, and buy a manual. Learn how carbs work and what each part does. Understanding is the key, learn as much as you can before tearing into a machine, and your results will be much better.

Let me say this first - I don't own a GS500. So I'm going off what I've read here.

But if I'm not mistaken, there is a separate fuel line from the tank for the reserve. So if you do have gas in the tank but nothing going thru when you flip it to reserve, that line / part of the fuel valve can be clogged. And it has been said before, that even when the tank is empty there is still gas visible inside.

Quote from: W201028 on July 12, 2015, 05:42:51 PM
It sounds like you are not very experienced, no offence intended, as everyone has to start somewhere. Do you have a friend that rides and wrenches?
Try to read alot online, and buy a manual. Learn how carbs work and what each part does. Understanding is the key, learn as much as you can before tearing into a machine, and your results will be much better.

Yes on friendly rider, questionable on wrenching.

My read on things is that if it is too rich, I should be able to check the sparkplugs, the Haynes manual I have has some neat pictures for various conditions that can be occurring internally, and how they present on the plugs. Am I getting of on the wrong idea if I try to use that as an indicator?

Thanks for the answer though, WRT to carbs. Was worried it was going to come down to that.

The first thing I would do would be to check your spark plugs. The Haynes Manual is a wonderful resource, and what it tells you about the plugs is good. The colour of the plugs will tell you if the bike is running too rich (or too lean or perfectly). If it's running too rich then you can start investigating the carbs.

As for a fuel blockage, if you're getting fuel normally, but not when you switch to reserve this suggests a fuel line blockage. Check that one out. The other possibility is a fuel leak somewhere. It may not be too obvious as the fuel will evaporate very quickly so you may have to check while the engine is running.

Good luck.