Thanks Deejay
Yes you are right, I haven't had the sprockets/chains replaced in the 35 years I have had it.

So working on rough prices for parts from this website for 2 chains, clutch cork, cutter sprocket and engine shaft sprocket...maybe $160? I'm assuming these parts are all readily available?

I guess my best plan of attack is to remove the clutch to make sure there are no extra surprises before I commit to replacing the sprockets etc.

What do you think?