CRAN is correct. Two-stroke engines are not very reliable, but due to weight, they are used in just about all very light homebuilt helicopters. The following comparison is therefore not exceptionally meaningful, but it might be of interest.
The Mini-500 has a GW of
840 pounds and the engine is a 2-cylinder,
581 cc Rotax 582.
The Mosquito has a GW of
610 pounds and the engine is a 2-cylinder,
625 cc
Zanzottera mz202.
A little more info;
The mz202 is also a consideration for the 550 pound SynchroLite