Honda NC700, also with a parallel twin SOHC engine (not Unicam), valve inspection distance is 8000 miles/12,800 Km. (Note: schedule for the Fit car from which the NC engine is derived, recommends inspecting valves when they are noisy or 25000 miles.) I know, it's all very interesting but not helpful. Or maybe it is; if it demonstrates that Honda motorcycle maintenance engineers might be on the obsessive end of the spectrum.The other question:
Valve service interval? Here's to hoping >16k km. Most likely bucket over shim.
Maintenance schedule for the Pioneer 1000 (found here: http://www.hondaprokevin.com/2016-pioneer-1000-5-maintenance-service-schedule-sxs-utv-atv/), which shares the basic engine with the AT, calls for inspecting valve clearances at 1800 miles, 3000 km or 300 hour intervals.
Since motorcycles run at higher speeds than 1500-1700 pound, 4x4 SXS's (Pioneer) in cleaner air and generally impose lighter loads on the engine, 300 hours would seem to be most appropriate interval. To estimate distance, use your average speed per hour to determine the correct mileage to inspect valves. Or better yet, wait for Honda to release the maintenance schedule for the AT.:laugh: