first of all my wife comes from where you live and her family is still there.how were you affected by the floods
1979 yz400f
the 1979 yamaha is an update model.almost every brakeable engine part is only for this model.i have a it400f with a yz400f motor in it.you need to buy gen yamaha pistons for this bike.top end from a 78 wont fit.crank is different.
ebay will become you freind.also find a way to get stuff from the usa as there is abit forsale there.
speed and sport yamaha in pa have a few parts for this model if you cant find any were else.i ring then ang pay via c/c 10 days later the parts are on my door step.
cheers
jim
sydney
australia