Adjusting the belt tension on the TFR isn't difficult.
Remove the plastic side covers. Loosen the three engine bolts (2 front ones go all the way through both sides of the frame, while the third rear bolt is only on the left side), also loosen the rear exhaust bracket bolt. Move the engine forward, until you have good tension on the belt. You can use a screw dirver in the engine mount bolt slots, to pry the engine forward...then tighten all three mounting bolts, and the exhaust bracket bolt, reinstall the plastic covers, and test. I do NOT recommend running the engine with the clutch side cover off...it could be a real meat grinder to the leg!!!