Rear wheel horse power

My new to me GRiSO has about 100 hp at the rear wheel. Is that correct? I thought it would be about 110hp, or is it 110 at the crank

A standard 8V makes about 96 RWHP. When tuned and mapped correctly they make about 100. By stuffing around with loud pipes and other such nonsense you may be able to get a few, as in three or four, more at the rear wheel but it will come at the expense of bottom end and midrange torque. Fuel economy will also plummet.