Townboy:

The Helmut Bernhardt (HB) Feinmechanik delivered engines in eight sizes; 0.12, 0.15, 0.20, 0.21, 0.25, 0.40, 0.50, and 0.61 cid. The 0.12, 0.15, and 0.20 engines had lapped pistons, all larger sizes, from 0.21 up, were ringed. The 0.21 and 0.25 had Dykes rings, I'm not sure if the larger ones had Dykes or conventional rings. All HB engines had double ball bearings on the crankshaft.

Chromed cylinder sleeves were available for the 0.21 and 0.61 engines, PDP porting could be had on the 0.21, 0.40, and 0.61 engines.

The engines up to 0.25 came with muffler, the 0.40 and larger had none, exhaust to be user supplied.

All sizes and options could be had in a marine version with water cooling jackets. Additiionally, there was an oil seperator available for the marine versions.

The 0.21 also was sold set up for r/c car use.

Finally, the 0.61 was sold in a "StaMo" (Stationary Motor) version with a cooling fan and shroud attached.

Most service parts are available from RJL/MECoA.

I have the specifictions and parts listings for all these engines, if you have any further questions.

Bill.