This video accompanies a discussion on the Korider forum relating to the fitting of a Dynojet O2 Optimizer onto the 2010 Hyosyng GT650. I have since found out that a negative voltage is actually CORRECT! The O2 Optimizer ships as part of the Dynojet Power Commander 5 module which Dynojet state on their website is compatible with this model of motorcycle, but which I have later found is most certainly NOT. At least not in a plug and play manner.
Hyosung, GT650, 2bros, two, brothers, exhaust, PCV, O2, Optimizer