Hitchcocks Forum

has anyone any technical information on the royal enfield 250cc flat twin (boxer ) engine

? Never heard of it. What do you already know? What sort of period are we talking about?

REgards, Mark

The words flat twin, and boxer, i thought were synonymous with BMW..

Think they did make a single 250 pre war but it was a failure..

RE had the 250 twin Villiers engined scrambler but i don't think you mean that one..

Royal Enfield made flat twins in two sizes I know of, but they were much larger than 250cc and the largest, at least, was a diesel. I happen to have three of the larger ones and they are, sadly, far too large to fit a motorcycle frame. Regards, Paul.

Gwilly, as far as I recall the 250 Villiers engine twin was the Turbo Twin road bike.

Enfield (Not Royal Enfield) did produce a flat twin, two stroke 250cc engine diesel, it was a stationary engine.

Are you thinking about boat engines? There were Enfield flat twin boat engines and stern drive setups available. They may not be the same 'Enfield,' though.....

Correction to my last 250cc flat twin petrol:-

Well this one has everybody guessing. What Wetdog is possibly talking about is the little 250 2 stroke opposed twin produced by Royal Enfield in the 1940s as a stationary engine. Effectively it was 2 RE 125 engines joined by a common crankcase, and by common I mean that where most multicylinder 2 stroke engines have individual crankcase compartments for each cylinder this little beauty has only one for both opposed cylinders. Hence both cylinders scavenge fuel frome the crankcase at the same time and fire at the same time, not at 180 degrees apart like a comventional opposed 2 stroke would. It has the same ignition system as the 125 - a flywheel magneto and both cylinders still retain the RE decompressors in each cylinder head. Could it be fitted to a motorcycle frame? I don't think so as its performance would be very limited. But it would definitely sound neat firing both cylinders at the same time, especially with a couple of open megaphones that were used on some racing 2 strokes for that period. You can all stop laughing now at one of REs lost inventions. Regards.

250cc two-stroke boxer engine? I can only think of the Velocette Viceroy.