J.A.P. made tons of engines, powering everything from the mighty Brough Superior SS100 to humble stationary engines for farm use, so what makes this so special? Well aside from its excellent condition, it's a genuine antique - dating from the early years of the First World War. The previous owner told me it was either 1914 or 1915, and my own research had confirmed that it's from this exact period of the Edwardian Era. 

Having studied a bit about these early JAP motors from the accepted authority - "J.A.P The Vintage Years by Jeff Clew", the engine is 2 1/2 HP and from early in WW1.

Basically, J.A.P started including letters in their engine serial numbers from 1920, with the letter 'P'. From 1920 onwards it's relatively simple to date an engine, particularly motorcycle ones, but for the years 1919 and earlier it's a lot trickier, since the records aren't as organised. What is known for certain is that up to and including 1919 J.A.P bike engines had no letters at all, only numerals. This motor only possesses the serial code "1567", so even in the absence of the engine's design revealing its exact date of manufacture, it's absolutely 100% from 1914/15.

So what we have here then is a motorbike engine that's coming up on 110 years old, yet is ready to service, check through and tighten up and then fit into a vintage bike frame. I haven't opened it or examined it beyond the external check I gave it when I bought it - of course I've checked that it's all still turning over as it should, and can happily confirm that it does.

I was told that the bolts holding the crankcases together had, prior to rebuild, suffered corrosion so they've obviously been replaced by more modern day ones. They'll need ageing or replacing - either is a simple task.

The only thing I can see anywhere on the engine that's missing is the round plate on the face of the E.I.C Magneto, which I believe I have somewhere. If I find it prior to sale I'll naturally pop it back on - if not it'll be compatible with one from any cheap postwar magneto. A carb will obviously be needed too - any appropriate small AMAL should do the trick. 

The only sign of any age really is a handful of spots of very light surface corrosion on the top of the magneto and timing chest. This would have taken me a few minutes to sand off and touch up with black enamel paint but tarting things up isn't my style - anyone who knows what they're looking at will understand how wonderful the condition of this actually is without me having to try and shine it up here and there.

Please examine the photos carefully as they form part of the description. Thanks and best of luck.