Thanks all for your wishes and advice.
Yes I do wish it was only two valves per cyl, but then it wouldn't go as well.
I can source new valves, seals and carby rubbers from the states for just under $500.00 shipped, so probably won't bother with a used motor.
Went with the Gates belt, abt $42 as against Honda who want $208.00 for the same belt.
I've got it all torn down ( looks very sad
) and cleaning up while waiting for parts. Also a good opportunity to check all those things that are hard to get at when it is all in one piece. You find some interesting things though. Someone has put a car size fuel filter in, but they got it in backwards ( despite it being marked with an arrow that says "CARB" on the case) so it hasn't been filtering much.
Hoping to respray it while I got it apart as well. Depends on money > Paint ain't cheap either.
Anyway looking forward to parts arrival and getting it all back together.
Then RIDE, RIDE!!