g'day Mark,, they are indeed brilliant outfit bikes,
if you check out "members" and look for "Scarfey", also in Canberra, he might be able to point you in the right direction having rebuilt a couple of his own,
the avon tyre is pretty much it with these size wheels, with out going to a major mod like the rear wheels
as for the silencer and pipes, I do know of Joes motorcycle wreckers down there, he might be able to help out with that,
always plenty to tinker with on these old girls,,
welcome to our rapidly growing group
don't worry,, it won't take long to get use to the forum thing