Minor complications
Well, I received my package from Pirate Cycles in record time, but the replacement engine bolts did not fit properly, and I managed to break BOTH piston rings trying to slide them back into the cylinder. So, needless to say, I'm not riding anywhere in the immediate future.
For the record, the engine bolts Pirate Cycles sells individually right now on their website are stock Grubee studs - they are a 8mm 1.25 thread pitch and are not necessarily made from an upgraded steel as I assumed they were (stupid assumption on my part, their site did not indicate they were a higher grade). They do also sell a stainless steel hardware upgrade kit, and the engine studs in that kit are a 8mm 1.00 thread pitch. According to Justin at Pirate Cycles, the Grubee "80"cc engines use the 1.25 thread ptich, and the PK-80 motors (like mine) use the 1.00.
On the bright side, Pirate Cycles has been beyond awesome to deal with. Justin has answered every email quickly, and he even told me he will send me some of the stainless engine studs at no charge. As if that wasn't enough, he even offered to send me a replacement ring set at no charge, even though it's probably my fault they broke during installation. Can't ask for much more than that. I don't know if Pirate Cycles makes a habit of treating their customers with such reverence, but rest assured, they will be my first stop for parts and accessory shopping in the future!