I tried making a gasket ( I am the son of Sir Titus Canbee) but it didn't work. Went down to the shop and bought one ($7.50-a bit steep I thought). Put it on and it started first pull! Great. However, now it isn't getting enough air as it revs and chugs very slowly but if I unscrew the air filter a little bit it roars to life. Air filter looks newish. Oh well, one problem solved another one to overcome.
There is a bit of an art to making these gaskets, Vcomm is an expert at making them.