I have a line trimmer that I dont use anymore and I have been looking longingly at it with the thoughts of converting it to a plane engine. I realise this may have been done to death but do they fare OK? It doesn't have a rear bearing, will this matter?</p>

the ryobis are fairly popular, some of the older ones are 28cc (or was it 26cc?) and most of the more recent ones are 31cc (a lot more popular), this type can be identified by their rear intake and rear exhaust setup. The newest Ryobis are homelite 30cc engines, they are side intake and exhaust so it's easy to tell the difference

there are several places that have conversion parts out there, I don't remember this early in the morning, I make all of my conversion parts myself (that lathe has paid for itself now)