What else to do?

[JoJoDaClown]

My wife has a '79 GS750L and she's only getting 28 mpg on the highway. For initial steps before taking the carbs apart (don't really want to) I'm getting a Dyna S and the Accel Coil/Wire kit in the mail soon. I've run Seafoam through it a few times in the past year and it runs well. Can get it up to speed quite well. Plugs are relatively new, but will be replaced since the new plug wires need the nipple tips. Everything else is stock.

What else should I do? She's threatening a new bike, so anything is cheaper than that.

[tfb]

Have you changed your air filter? Even when they look clean, they can be chokked to the gunnels with crud, leading to rich mixture and poor economy.

[JoJoDaClown]

That is a good, and obvious, point that I have overlooked. I'll take care of that.

Anything else?

[KGB]

And make sure all the spark plugs ends are conencted?
as in they actually are on the plug? Or functioning?

[JoJoDaClown]

Alright now, I have done more than my fair share of wrenching, including building engines, but it's all car/truck related. I'm not exactly used to 4 carbs and the smaller package. So I guess I'm looking for more than just cleaning the air filter and making sure the boots are properly connected to the spark plugs.
Are there carb settings that should be checked to ensure proper air/fuel mixture? I've set the air screws to 1.25 turns out as the manual states. Where are the jets located? I should probably clean the seats.