It is a great bike, I have had my '83 GS750ED since buying new in 1984. It has seen a wide range of mods over the years. In stock trim it was very restricted and lean - and slightly slower than my friends then new 1985 VF700 Interceptor. Once moded with carbs, cams and a pipe it would run away from his Honda at all speeds.
Parts/aftermarket items can now be hard to find for a 20 year old bike with a very limited production run. In the US, 1983 was the only year for this model GS750.
1983 was the first year for the new design, in 1984 Suzuki did not bring a 750cc machine into the US because of the Harley tariff. The GS700 was introduced for 1985 at 699cc to slip under the tariff.
1986 brought the GSXR into the US and these bikes were forgotten about by the mainstream.
Most '83 GS750 parts will interchange with the 1985 GS700- some internal motor parts are different, slightly different bodywork, and different gearing.
Like any GS bike it will benefit from changes in intake,compression,exhaust. Performance mods on this bike will really open up the upper midrange and top end.
Early (1986-87) GSXR CV flatslides were 31mm and 34mm, they are a definite improvement over the stock GS carbs and they will bolt right up and use the stock throttle cable. The 34's off the 1100 will work best - aftermarket Mikuni 34 RS smoothbores if you have the cash.
GS1100 performance cams will work, aftermarket cams in the .330 lift range work well, are full drop-in, but aftermarket springs recommended. GS1100 manual cam chain tensioner will also work.
Stock compression is at 9.6-1, the 699cc motor's pistons are the same 67mm bore as the 747cc motor but are domed to make up for the compression loss by destroking to 699cc. They will give around 10.25-1 in the 747cc motor. 10.5-1 is a good number for the street unless you have access to some good high octane fuel. Aftermarket Wiseco 816cc kit (10.25-1) is the best route if your gonna do a piston swap.
Dyna or Accell coils and wires - open the plug gap to .035
Exhaust systems are getting hard to find but any good old 4-1 will work. MAC pipes are on the bottom of the list with a good used V+H, Yosh, or Kerker up top.
The above mods will yield a good street bike with about 85-90 bhp and around 480lbs with fuel. With a big bore kit, my bike would loft the front wheel in 3rd gear at around 7500 rpm.
My '83 is in parts now waiting to be rebuilt for the last time. Photo below shows her in her prime with the ES bodywork and today as she sits.
Good Luck, Ed.
1983 GS750ED
2005 GSF1200SZ
1992 900SS
And BTW, once all that is done we will need to talk suspension