Finally i found something:
Thunder Tiger - PRO-50BX (R)
Product No. TTR9445
tdunder Tiger's PRO series engines are equipped witd dual-ball bearings, Schnuerle porting, ABC type piston and cylinder and
mixture control carburetor.
Specification:
Displacement: 8.19 cc. / 0.500 cu. in.
Bore: 22.5 mm. / 0.886 in.
Stroke: 20.6 mm. / 0.811 in.
Practical RPM: 2,000 ~ 30,000
Output: 1.80 BHP / 16,000 RPM
Weight: 465 g. wo/muffler / 16.41 oz.
http://www.thundertiger4u.com/pro50bx-r-p-7554.html