Originally Posted by Sunfighter
Vexor is the resident GSXR expert ... he'll chime in as soon as he sees this I'm sure.
jeez, putting all the pressure on me....
I'm not too familiar with the older bikes but doing a quick search on Suzuki GSX-R Motorcycle Forums: Gixxer.com
it seems like the 04/05 models are known to have starter button issues (apaprently cheaply made and could break or overheat) and a STVA (secondary throttlebody valve assembly) issue. Apparently that throws a C28 code on the dash.
Other than that it's like any other vehicle. Make sure it's been maintained and had its fluids flushed at regular/recommended intervals and if it's got more mileage check to see if it has had the Valve clearance adjustment done.