60cc of 10k RPM WOT, but super torque that will pull all day and rattle your teeth. I've got its big brother, the 245. Same bottom end, different slug and jug (think MS650/660).
Replacement parts are available around the internet, but crank seals can be difficult to find. One side (the flywheel IIRC) is a standard size and still in production. The other side however is an odd combination of dimensions and is no longer made. They are out there though.
When I did the rebuild on mine, I dumped the obsolete points ignition and put in one of those Oregon solid state modules.
The carb has a mechanical governor built into it. It's actually pretty neat considering it was designed in the late 60s/early 70s. When it senses a particular vibration, it opens some ports and dumps fuel into the intake, dropping the RPMs. When you tune it, start with the high end VERY rich, and work your way into the 2-stroke note. It is easy to confuse the 4-stroke note with the governor kicking in.
As for mix, I'm running mine at 32:1.
Also, Oregon did make a rim & drum for the 306/245. It is now obsolete as well, but again, look around because they are out there.