Putting a fuel gauge on a bike without one...
 

This is not for my bike (obviously) But for my wifes GS500. The damn thing doesnt have a fuel gauge, and while i have told her to watch the tripmeter and to physically look in the tank to determine her fillups, id feel better with her having a gauge. Since she is newer to riding, she also asked me about some kind of gear change indicator. Basically, something that would tell you what gear youre in. (ive seen a few of them on youtube, just a digital display numbering what gear youe in)

I have looked up stuff for a while, but considering you guys have been around bikes alot longer than me, i figured id ask for any info you might be able to provide.

The one solution i have found might be this: http://www.veypor.com/veypor.html

I just dont love the $159.00 price tag. But,in the end, if thats what i have to get, i will.

Does the GS have a petcock with a reserve setting?

You'd need to find a fuel sensor, cut a hole, and mount it so that it appropriately measure the fuel.
However the GS500 has a petcock with a reserve switch, so just tell her to drive till it cuts out, switch it to reserve, and go to the nearest gas station. She'll learn when it will start cutting out.

Killer,
It does have a petcock and reserve.

Nick,
I just dont want it to cut out on her while shes riding to work on the expressway and cause a potentially bad situation. Thats why i was thinking about that Veypor unit in the link. As far as cutting the hole and finding a sensor to work... ehhhh i might just get the Veypor unit lol.

Short of cutting a hole in the tank to put in a sensor, I think the veypor unit is going to be the way to go. I'm thinking you'll still need ot set some sort of baseline with the veypor. I don't imagine it can guesstimate fuel tank level without something to work off of. For example you ride X amount of miles, probably start with a full tank and ride till you hit reserve, and then tell the unit that is the fuel tank range. Either that or you might be able to program in some sort of precalculated mileage. The only way I guess it figures out gas tank level is by the distance you've ridden.
That's my two cents anyway.

Thanks for all the input. Ill probably save up for that thing seeing as how i really dont want to cut into a tank just yet