On the way home today I fueled up at 208.4km [130miles] odometer reading and used 6.88L [1.77gal] this works out to 73.4mpg. this is seated upright at posted highway speed limits, without hypermileing. The gains are all from aerodynamics, windshield extension, area behind legs is filled in with styrofoam 'sadle bags', which will become rear sadlebags now that I know they work, the front forks are streamlines and some parts of the fairing are extended or modified for better aerodynamics. The front sprocket is changed from the stock 16 tooth to a 17 tooth. In the near future I will replace the stock 39 Tooth rear sprocket with a 33 tooth sprocket, this may get me down into the 2.?L/100 [80mpg] zone and at some point I hope to get 2.5L/100km [94mpg] seated upright without hypermileing... on my Suzuki GS500F motorcycle. some hypermiling and i could give those Kawasaki Ninja 250 a run for there money?
Going down 6 teeth on the rear sprocket is quite a big change for a small displacement engine, especially after you already went up 1 tooth on the front.
But I guess you never know until you find out
On your pics I see the bike still has its original Suzuki indicators, wouldn't flush or smaller indicators cut down the drag ?
On the rear, maybe you could work them into the rear fairing ?
You are right about the turn signal lights and that is on the list in my head. For now I will work on the sadle bags as they provide utility as well as aero. I have had the sheet aluminium bent to size and shape and instalation may provide an oportunity to incorporate the rear turn signals.
The rear sprocket may cause some problems when getting underway from a stop, the clutch may have to be let out more gradualy. But without trying it I can't be sure. I also have a 37 tooth rear sprocket if the 33 causes problems. I will keep the 33 tooth sprocket in for one tank; 15L, just to see what FE I can get.
I have installed the 37 tooth rear sprocket and will commute as much as posible next week to see how much things improve. This change will drop the rpm by 5%. I am still thinking about providing warm air for the carbs but have not fabricated anything yet. I am thinking of building a shraud around the exhaust just infront of the muffler and running a 1 inch flex hose/tubing to the air filter box. I will need to find some way to moniter and adjust the intake air temp. If you are interested in seeing pictures of the bike and its mods Just click on Gray - '07 GS500 F on the left. When the sadle bags are done I may try a removable boat tail to see what can be achieved. What I hope to achieve is 50% above EPA of 60mpg to 90mpg or better. The other challenge is the standard set by the Kawasaki Ninja 250 which gets over 100mpg. Does any one else have a medium size [under 500cc] bike that they are modding for better fuel economy. Lets start a new thread on the motorcycle section.
The present configuration gets 2.8L/100km / 83 mpg [three tank average] and is the bike I will be taking to the Vetter Challenge in Carmel, because the VT500 will not be finnished in time. If all goes well this summer I may be able to go to the Vetter Challenge in Ohio in July, with the VT500.
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, because the VT500 will not be finnished in time. If all goes well this summer I may be able to go to the Vetter Challenge in Ohio in July, with the VT500. 
