RE: Old Soviet Union 10cc engine
They are actually quite powerful but shake like a paint mixer. I took mine apart and lathed out the inside of the piston and drilled holes in the crank but still could not get it anywhere near balanced. More of a collector's item. One more thing. The standard Russian plugs are 2 volt, not 1.5 like ours. Swap it out and use some nitro and it will run.
Max[8D]