I did some reading up on Li-on cell charging basics and i think i get it now.
The nominal voltage of the battery is around ~104v. So for an Empulse TT its rated at 100Ah and for the Brammo Empulse its around 90Ah. These are the 1C rates for the batteries for the 2 bikes.
Right now i see that my TT charges at around 24A DC which is about 0.25C. I guess we just need a charger which can produce somewhere around 0.5C worth of DC at the same voltage rate (104V). This could potentially double the charging rate. As far as i know keeping the charge rate to something less than 0.5C will keep the battery life optimal.
So yes, this 6.6kW wont work since the voltage range exceeds out of the battery's voltage capacity. We would need an onboard charger which has a voltage range of 50-122V (something like the charger thats currently on the empulse) with a higher C output. Based on that we might need a suitable DC-DC converter too (not entirely sure if the stock converter gets the job done).
Or an arrangement with 2 chargers which is seemingly more complicated.