PLEASE change the oil BEFORE starting and put some oil down the bore, kick it over, with the spark plug out and then with a 50:1 two stroke oil mix in the tank, give it a try. I've seen good motors wrecked due to over enthusiastic "Must hear it run and revving, before any preparity work, or time to warm through! :'( :'(
I too would give it a clean and leave well alone, once the wiring, tyres, tubes etc are sorted. As for tyres, I think compounds have come a long way since 1976, so it should stick to the road better than my experiences.
All the best with the wee beastie Martin and good health, Bill