I seem to recall being able to do this from my motorcycling days of long ago, seems to me you could swap jug, head and piston from 110 to 90 is this true and while Im at it, when I shut this one off something spins down for a second or two, I dont remember the last one doing this I assume its part of the centrifical clutch business, normal or do I need to check it out...it sounds a little dry to me.
