I have the engine. The engine does not come with any holes in the piston. The crankshaft is NOT weighted. I noticed they took all the pics of the engine off of their website as soon as the engine hit the USA. I know of several people that purchased the engine and were dissapointed to see a completely different engine than what was on the Novarossi website. The practice engine looks like a standard plug Novarossi RS12 from a several years back with an updated piston/sleeve/rod, and the crankshaft is 11.5mm. Certainly not as fast as the newer Novarossi engines. I am sure someone will post how the practice engine runs soon enough. I will be testing the engine soon.