The R-2 glow-plug motor was a shaft-valve twin ball-race unit of 4.86 cc displacement which was manufactured to quite good standards in Shanghai, People's Republic of China beginning in 1965. Although displaying obvious Super Tigre G.21 influence, it departed from the Super Tigre design in using a separate bolt-on backplate, a forward-sloping FRV intake and ultra short stroke internal geometry very much along Dooling 29 lines. Bore and stroke were 20.4 mm and 14.9 mm respectively.

The engine featured a rather heavy ring-less lapped cast-iron piston with a transverse baffle formed towards the transfer side. Together with a rather massive crankshaft, this contributed to the engine's seemingly excessive weight of 240 gm (8.47 ounces) less glow plug - a lot of weight for a 5 cc engine. Reciprocating weight was also seemingly on the high side.

Responsibility for the manufacture of the R-2 remains unclear at the present time. It is possible that it was produced by the same Shangai companies that produced the Yin Yan and Silver Swallow 2.5 cc diesels, but this is far from certain. A pointer to this possibility is the fact that the R-2 had an almost identical companion (or successor) which was marketed under the Silver Swallow banner. This model was very similar to the R-2 apart from featuring a plain un-finned cylinder head. 

The R-2 had a larger sibling which was marketed as the R-5. Details of this model are unavailable at present. A more detailed description of the R-2 and its companions may be found elsewhere on this website.