Empire V-Twin - Feature Bike     

About us

Emu Engineering has been involved with the BSAMOA and the All British Rally for many years and, apart from building the occasional special motorcycle, mainly builds large electric motor starting equiptment; upto 650 HP in 415 Volt. We also offer a large range of second-hand electric motors to heavy industry for a variety of purposes, including; mining and Quarrying, pumping, saw milling, refrigeration, etc.

I thought you and your readers may be interested in my latest creation inspired by the brilliant designer Val Page and built by me- 'The Empire Twin'. BSA built their last OHV 'Twin' in 1938 and although, very attractive, by that stage was a fairly dated design and certainly not robust enough to extract the high performance desired. Having raced BSA's, a B33 that ended up as a DOHC- 4 valve, 1000CC Rocket 3 and BSA's cousin- a Norton Rotary, I fancied a bit of a challenge. I thought of the idea a few years back, but it always seemed to end up in the too hard basket. Other projects and never enough time seemed to be the never ending excuse.

Anyway, about a year ago I put work (slightly) to one side, the excuses to one side, and got into it. After dinner, and much to my very understanding wife's dismay, I would drag out bits of BSA singles and start designing. I built the crank using a pair of 94mm/ M20; drive side fly wheels, re-machined to accept a pair of American S & S- knife and fork type conrods.

I made the patterns for the crank cases and cylinders and had them cast at a local foundry. The crank cases, although having very similar dimensions to the M & B series singles- and do share mounting hole dimensions, are however substantially heavier, especially around the four main bearings, which in this case are all rollers. The cylinders; cast in alloy and fitted with iron liners, are bored not to 82mm- as an M23, but 87mm; as I had an ideal pair of pistons begging to be used. The end result, using an almost flat top piston, I was able to gain a 9/1 compression ratio- with good squish and a very handy 1120CC of grunt. I first fired up the engine on the test bed after about 700hrs of work, which included design, patterns, basic jigs and fixtures, machining and assembly. Then I thought to myself "Now the tricky bit is done, let's do the easy bit... the rolling chassis". Bearing in mind the original goal was to create a bike that would not look out of place in a 1939 catalogue, I set about the task. Well, by the time I had stretched an M20 frame and tank, built an oil tank, twin-drum front wheel, special gear-box, special alternator bracket; so I could utilise C11G chain cases, hung all the cycle parts, and repaired all the old, worn out parts; somehow another 700hrs seemed to sneak past. I finished the bike just in time to ride it to the 32nd All British Rally (the biggest and most successful of its type in Australia) - where it was judged the 'Best Bike of the Rally'.

If I had managed to finish the twin 6months earlier, I would have probably taken many friends advice and shipped her off to England, instead of my trusty Gold Star Special, for the 2008 International at the Empire Twin to Queensland for the 4th National BSA Rally to be held on the Gold Coast from the 5th to the 7th of September, and providing i get back from the UK on time

Happy Beezering,

Doug Fraser

Emu Engineering

+61 3 9775 1906 .