I checked my manual, only says to check valve clearances at 250hrs.
However I see an online manual http://www.manualslib.com/manual/208...?page=5#manual
is recommending to check at first 50hrs, then every 250 hrs. So disregard what I say!
I just remember the dealer telling me this with the Hustler, then when I did take it in the mechanical told me there was no need to do it. So I assumed they were giving me a load of crap when I bought it, so I would bring it in for a paid service! They never ended up checking it, but should have.