JBA 52 pt.1

Glance at the picture on the right there and there's no need for me to tell you that the subject of this review looks pretty striking in blue. Actually, it's very blue, and to all intents and purposes is a typical, nicely made, Chinese engine like all the others in this category. This is no bad thing, for without such Far Eastern manufacture the range of engines available to us would be very limited. The Chinese have been hard at this game for a couple of decades now and their engines are arguably amongst the very best out there. I've probably reviewed and tested a couple of hundred or so Chinese model engines, and few (if any) have been lacking. As such, I fully expected good things from the JBA, so let's see how it performed.

JBA engines are sold in the UK by Model Hangar, a new company to add to my database of engine folk. Take a look at their comprehensive website and you'll immediately see that they mean business, with a very clear and easily navigable set of web pages. This approach is quite refreshing, given that some engine makers remain positively coy about revealing their all on the 'net. Some time back I wrote something to the effect of ‘be there or be square’, i.e. if you ain't on the 'net then you ain't in business, mate… an ethos that I stick by. Who uses Yellow Pages these days, or an answerphone even, with internet and e-mail so readily to hand?

Okay, so JBA has their infrastructure in place, with claimed spares and factory back-up to rival the best. Let's have a look at an example of their wares in the form of the JBA 52 two-stroke – a common enough beast in the grand scheme of things in that it's a reasonably-priced 52 glow engine for general sports use and probably of similar performance to others out there. We established earlier that the JBA livery is very blue, and I rather like it. We already have Irvine red, O.S. blue, JEN purple, GMS gold and so on, so painted or anodised engines aren't exactly uncommon now; a trend that has more to do with looks and an immediately identifiable corporate image than anything else (not that there's anything wrong with that). The JBA 52 looks very natty, then, with its highly polished details, and it all comes well packaged with instructions and a large muffler in an equally smart and equally blue box. Splendid!

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Instructions first, then. These are always my first port of call, as indeed they should be. You don't get much, just the one sheet of A4 printed on both sides, half of which is taken up with the usual dire safety warnings… 'caution' and so forth, which is all very normal in this era of litigation. Moving onwards and over the page there are more interesting bits of blurb, including the 'initial running' section followed by basic information on fuels, plugs and the like, and a small data quadrant gives figures and recommended propellers for the entire JBA range. The instructions cover all the basics but no more. Not that you need more, I guess!

With the instructions neatly folded away, my next task was to take this nice new shiny engine and completely dismantle it… purely for the purposes of this review, you understand. This is something that you absolutely should not do, although in bygone times this would have been normal for 'real' engine types, given that half a ton of swarf and rubbish might once have been discovered lurking within the innards of a new one. But those days are long past. I never find machining residue in engines nowadays. Oh, and don't forget that to dismantle your engine, of course, invalidates the warranty, so don't do it!

The JBA 52 came apart in about a minute, two at the most, this being down to perfect fits that were neither too tight nor too loose. Most modern small-to-medium two-stroke glows are the same, thanks to the unerring accuracy of the CNC machines that turn out thousands of identical parts with little or no human intervention. There was a time when blood, sweat, tears and bad language accompanied any engine strip, but today you seldom need more than a little heat, which is why today's motors last longer and wear slowly. And if you use a good fuel then engine wear is almost non-existent. It's quite amazing, really.

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Stripped and laid out on the bench, the JBA revealed its secrets. It has an ABC cylinder and piston set-up (i.e. an aluminium piston running in a brass cylinder liner with the bore chromium plated), a proven and commonly employed arrangement. Supported by two ball race bearings, the crankshaft is a hefty unit of one-piece construction (i.e. the crankpin is machined rather than pressed into the web as a separate component). All the castings (pressure die) are extremely clean, and the machine work, both inside and out, is as good as anything I've seen. All good news so far, then.

The 'muffler' (no, it's not a silencer – show me any engine that's silent in operation) is a large, highly polished tube and cast end cap arrangement that's similar (identical, even) to the GMS and JEN range, which probably exposes the origins of this engine! The carburettor is a twin needle type, again identical to many other engines out there and none the worse for that, being of proven design and construction. All in all this is a thoroughly competent piece of work.

The next task is screwing the thing together and starting the practical testing, which you can read about in Part Two of this review.

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