Had the same ticking on mine a while back and it was valve clearance, went away once they were shimmed properly. Worth checking first since it's the cheapest thing to rule out. The low rpm hesitation was a gummed up pilot jet on mine, sat for a while before I got it. For parts I've used Iron Offroad, they carry MX and enduro bits by bike and brand so it's easy to find what fits, though older Scorpa specific stuff is hit and miss. Yamaha engine manuals are usually findable separately since the motor isn't Scorpa's.