Starting with a bones example (missing its piston, connecting rod and mixture control needle) we start out to produce another fine runner of this rare little British engine.
Below is a picture showing the Bambi, the Dart and the Spitfire from my collection.
Below we have a replica box and and manual for the engine.
The biggest problem we face with this rebuild is the missing piston and connecting rod to use for scaling the dimensions for making the new items. Using pictures of a disassembled engine we constructed dummy parts for working out the porting and final piston and rod sizes.
The tank was made from cigar containers which I got from a tobacco shop around the corner.
After a lot of work the fits are actually not that bad; I added a few nice touches including a ball end on the mixture control needle.
According to published test data I should expect to produce somewhere close to 0.087 horsepower and turn up 12,000 to 14,000 r.p.m. I mounted a 8X4 propeller and this one screams like a banshee: must be because of my improved porting, that I developed for this specimen.
Watch the clip below of the first run of this rebuild engine with a tight fitting piston which will require a least 5 or 6 more runs with extra oil before parts will be acceptably run in for normal use.
Watch the rebuilt engine during one of its first bench runs.