ROYAL ENFIELD BULLET
Could you build a bike that’s better than new? Karl Moxon bought one of the last carb-equipped Enfield 500 singles and set about making his dreams come true…
Could you build a bike that’s better than new? Karl Moxon bought one of the last carb-equipped Enfield 500 singles and set about making his dreams come true…
In the mid-1960s, I was a sixthformer at school but more of my time was devoted to poring over the fine detail of Motorcycle Mechanics than studying my set books. My weekly income, ten shillings earned as a Saturday morning errand boy for the Co-op, stretched only to running an aged, well-worn, rigid and teles BSA B31. One magazine article made a huge and long-lasting impression on me. It concerned a man who owned, ran and maintained an immaculate Ariel Square Four. The article concluded by saying (and I remember it so well that these words are almost a direct quotation) ‘Here is a man who wants, and actually gets, a motorcycle that is significantly better than the day it left the factory.’
Wow, I thought. What a tremendous position to be in. One day, perhaps…
Four decades and more went by. A wife and two daughters came along, and my career progressed. I could afford much better motorcycles: a series of Japanese exotica, followed, as maturity increased, by a long line of BMWs. Excellent and enjoyable though all of these machines were, they were nevertheless somehow not really my bikes. For a reason which I couldn’t put into words (although was it, perhaps, a touch of envy?), it irked me that it was not down to anything that I myself had done that they would effortlessly perform every task I asked of them. That magazine article continued to haunt me. One day, perhaps…
By late 2007, the prospect of retirement became a reality. I vowed to try to make the dream come true. But what to buy? Although I had acquired a modicum of ability with a set of spanners, I was not a trained mechanic or engineer. Would a project bike be beyond my capabilities? And to buy an old British iron that had already been fully renovated would have defeated the object of the exercise.
Then I had an idea. How about an
Indian Royal Enfield? Though I had never before owned an Enfield and therefore felt no particular affinity to the marque, I reasoned that buying a brand new‘old bike’ would enable me to start from a known and hopefully solid base, and build from there. Furthermore, I would be able to treat it as a rolling project: ride the bike during the decent weather, and fettle and improve it, bit by bit, during the winters.
Enter Albert, a 2007 model Classic 500ES, which I bought in the November of that year. By then, carb-fuelled Enfields were no longer being manufactured so I grabbed one while there were still a few available, although I did not register it for the road until I finally finished work in 2008. Over the next four winters, I carried out a range of modifications and improvements. As can be seen from the summary in the sidebar, the quantity and complexity of the work undertaken gradually increased as my confidence grew.
One of the things that annoyed me once I began working on the bike in earnest was its wide and seemingly random variety of threads and hexagon head sizes, and the constant irritation of needing to seek out the correct spanner. The quality of the bike’s fasteners also left a lot to be desired. I therefore determined, as an ancillary project to the ongoing revamp, to replace each and every external fastener with stainless steel. Wherever viable, I would also standardise on metric threads.
Simple nuts and bolts were for the most part purchased commercially. But replacing the studs proved more problematic: as these all used imperial threads (mainly 26tpi cycle), the frame lugs had been tapped out accordingly. My decision to metricate therefore meant that their replacements would have to have a different pitch of thread at either end. Clearly, these would not be over-the-counter items; I would have to make them myself.
So I bought a lathe, and with the help of a friend who had recently retired from his own engineering business, learned how to turn, face, part off, screw cut and mill. Oh, what fun this is! It has been immensely satisfying to spend a whole day in the garage producing, for example, a few double-threaded studs or a matching set
of four shouldered nuts. By the summer of 2012, I thought that the project would be pretty much finished. However that was not to be...
Despite my best efforts, the Bullet had never really run properly. I suspected the carb, so on the advice of ‘knowledgeable’ friends, decided to try an Amal – initially a Mark1 concentric, and then a Monobloc. But neither improved matters very much. And then disaster struck: the engine main bearings collapsed. Time for a complete rethink!
I had put in the high compression piston because at that time it was the only forged one available. In the meantime, however, Hitchcocks had added a standard ratio forged piston to their Bullet accessory range. So why not try putting the bike back to more or less factory specification? At the very least, I would be sure that I would no longer be over-stressing anything. Thus out came the engine for a full rebuild: new main bearings, for safety’s sake a new, roller-bearing big end, a second rebore (this time to plus 40) with a 6.5:1 ratio piston, and back to the stock Mikcarb fed from a traditional tea-caddy containing an
S&B air filter.
Sorting the fuel/air mixture from thereon proved relatively simple. I was surprised just how little extra richness was in fact needed to compensate for both the still-modified cylinder head and the far less restricted, stainless steel exhaust system I’d also had made. The bike ran far sweeter too; dropping the compression let it rev much more readily than it did with the higher ratio piston.
Since then have come the final tweaks. A pal in the Royal Enfield Owners’ Club alerted me to an article by Paul Henshaw about Bullet valve timing. Apparently, quite some years ago the boffins in Chennai had advanced the inlet valve timing pinion by one tooth, in order to help lessen the engine’s emissions. That was fine as far as it went, but it had also adversely affected output. So, heeding Paul’s advice, I put the pinion back to the Redditch specifification – and wow, what a difference! A very useful increase in mid-range and top-end pulling power, with only a slight loss of low-rev torque.
Sprag clutches are a renowned weak point on (as well as other pre-EFI Enfields) the Classic 500ES: mine had eaten five in eight years. When, therefore, the upgrade to the electric starting mechanism researched and produced jointly by Hitchcocks and the French company Alton became available, I jumped at the chance of stopping the rot. Not a cheap exercise by any means, but worth every penny.
Other electrical items have also been upgraded: a new alternator, a better quality
regulator / rectifier, a German-made PVL coil, Boyer Bransden electronic ignition and an iridium spark plug.
So Albert is finally finished. Has the exercise been worthwhile? In purely financial terms, almost certainly not. Even without taking any account of my own labour, the bike now stands me at about double what it initially cost, but it would not fetch anything like that on the open market. It is however insured for an agreed value of £6000, so if the worst were to happen it could (in theory at least) be replaced. In terms of overall performance and reliability, on the other hand, the answer is most certainly ‘yes’. Some of its features which I now most enjoy are the combination of the progressive fork springs, Hagon rear shocks and Avon Roadrider tyres, while the windscreen, raised handlebars and quality dualseat ensure both decent road holding, and relaxed, all-day riding comfort.
The Alton modification to the electric starting mechanism means that the bike now starts on the button, first time every time. And although I’ve covered only a few thousand miles since this system was installed, the current sprag clutch seems to be holding up well.
Due, no doubt, to the combination of its reworked cylinder head, free-flow air filter and a much less restricted silencer, the engine now breathes properly. Gone are its original strangled feelings and the associated reluctance to pull.
Upgrading to a five-speed gearbox has given rise to three distinct (though all extremely welcome!) improvements: the irritating false neutrals inherent in the old Albion-type box have gone, the ratios are much more evenly spaced, and the gearchange action – although still some way short of a modern one – is appreciably smoother. The raised gearing provides relaxed cruising in the 50 to 60mph range, which is ideal for where the bike is truly in its element, namely on winding rural roads.
The electrics are 100% reliable; these days, I never even think about them. Particularly pleasing in this department is that now it is electronic, the ignition is always spot on, and needs no maintenance to ensure that it remains so.
Above all, however, it is in personal terms that the project has given the most satisfaction. I’ve now got a 1950s style motorcycle which (in my eyes at least) looks good, pulls like a train throughout the whole of its rev range, and will if called upon readily exceed 70mph. Just like a proper British 500 single should, and in marked contrast to the emasculated and under-engineered offering as which it started its life.
Albert is now truly my bike. For eleven years I’ve nurtured him and watched him grow. And although there have been numerous setbacks along the way, I am now where I dreamed of being more than fifty years ago. I not only want, but have actually got, a motorcycle that is significantly better