ROYAL ENFIELD FURY!
At the end of the 1950s, Royal Enfield created a competition-spec, big single, dirt-track desert scrambler. Very few furies ever made it back to Blighty, but fortunately Paul Henshaw has plenty of experience with big-head Bullet racebikes.
At the end of the 1950s, Royal Enfield created a competition-spec, big single, dirttrack desert scrambler. Very few Furies ever made it back to Blighty, but fortunately Paul Henshaw has plenty of experience with big-head Bullet racebikes..
Photos by Paul Henshaw, David Sowden, RC RChive
The Royal Enfield Fury was the scrambles version of the final, big-head model of the Redditch 500 Bullet. Aimed at BSA’s DBD34 competition models, it was probably a case of ‘too little, too late’ and not very many were made; around 190 is the number usually quoted. The Gold Star certainly had much more time to evolve and gain acceptance, while the RE scrambler appeared to be much more of an afterthought – not much more than a few trick parts stuck onto the standard Bullet 500.
The hottest of these go-faster additions was the cylinder head, also seen on the last roadgoing versions of the 500 Bullet. In Fury spec it boasted a massive 1½” inlet port to go with the equally large Amal GP
carburettor. Mechanically, the Fury differed from the last Bullets only with this larger inlet port, a lighter flywheel assembly, higher compression ratio (several options were available) and the hotter ‘R’ cams.
They still used the same old alloy conrod, though, and this just wasn’t really up to the sort of engine speeds and stresses the high state of tune imposed upon it. Indeed, I have witnessed conrod failures myself. Not pretty. If RE had fitted a forged steel conrod, perhaps things might have been different. If conrods hadn’t broken during US dirt track events, perhaps more Furies might have finished more races, scored more successes and so more might have sold. Who knows? Certainly, these days, a Fury-spec engine tuned for racing can take many more exotic and expensive machines (and spectators) by surprise on the racetrack. Fitted to a shortstroke 350cc race engine, that cylinder head can cope with 9500rpm, well out of the comfort zone of an alloy conrod! What might have been...
The machine featured here first came to my attention quite a few years back, at the Telford Show, on an auctioneer’s display stand. It looked to have been fully restored. I took a picture or two and thought no more about it. A little while later, I was approached by Llandow Classics, who had a customer with a Royal Enfield Fury. They had got it running and MoT’d for an owner who had bought it in an auction, and they recommended me for the other work the new owner wanted done. As it turned out, this work became a top end and gearbox rebuild, followed by what we might call ‘intermittent development’.
Initial findings were, in spite of the bike’s showroom appearance, a very worn out top end with valves waggling around in their guides like a stick in a bucket, and a cracked cylinder liner. Also, more alarming, was the lack of an oil feed quill bolt seal in the worm nut on the end of the crank! Luckily, the machine had only been run for a few hundred yards, if that, and no damage was apparent. The top end was rebuilt with new parts and the lubrication system received attention, including a seal for that worm nut…
I recalled that a 389 Amal Monobloc carb had been fitted when I saw the Fury at Telford, as you might expect to find on the ordinary, roadgoing big-head Bullets. By the time the machine arrived at my
workshop this had already been replaced by a more suitable (but not period) 38mm Mk2 Amal Concentric. This made starting very easy and all-round running generally pretty good. However, early test rides proved the Lucas N1 magneto to be suspect, so this went for a short visit to Tony Cooper for an overhaul and a job well done.
Another problem showing similar symptoms to the tired magneto turned out to be a blocked vent in the fuel cap. After about five miles, the engine would falter and die. I pulled into a layby with the engine spluttering. Thinking it was running out of fuel, I removed the filler cap to take a look, where the engine immediately picked up and ran normally. I continued towards home, with the fuel cap loose…
We experimented with many aspects of the e Fury’s set-up to make it suitable for its owner to ride. Most of these were engine related, such as several combinations of main, pilot and enrichener jets; different slide cutaways, and retarding the inlet cam – all to try and make starting as easy as possible. I didn’t find d it too difficult to start myself but he seemed to struggle. We have to bear in mind that this s state of tune was RE’s answer to the BSA Gold d Star. It’s easy to understand that the Fury, like e the Goldie, wasn’t a machine for everyone. I even modified the decompressor, so it could be set just cracked open, to reduce the compression a little to make starting easier. Then once the machine was running, it was just a matter of flicking a latch to restore full compression.
Other changes included removal of the knobbly Avon tyres and the fitment of a pair of modern Avon AM types, as well as raising the gearing from scrambles spec to something a little less frantic for today’s roads. The Fury came and went quite a few times over the next few years, with small detail changes and work carried out as the owner wished. Eventually, he gave up and sold it. I probably enjoyed this machine far more than he ever did, but all good things must come to an end ... or must they?
A few months later I received a call from David, who had just bought a Royal Enfield Fury. It was the one I had worked on and what could I tell him about it? Well, I could tell him rather a lot, as it happened! I mentioned that still used what might have been the original alloy conrod. David paused briefly, then said ‘Well, I think I would like a forged steel one. Can you fit one if I bring the bike over?’ Yes, I could. I even had a Redditch crank already fitted with one, which was now surplus to my own race bike’s requirements. That redundant crank would do fine for the new owner, then.
Interestingly, the replacement standard Redditch crank, which I’d already lightened for racing purposes, turned out to be exactly the same weight as the special lightweight Redditch Fury crank which came out of the Fury engine. Spooky.
Another important thing became apparent with the engine stripped. The outer race of the timing side main bearing fell out of the crankcase without any action on my part. This did not look good at first but, amazingly, it turned out someone had fitted a metric bearing. This was almost the right size, but not quite. I bought a Hitchcocks timing side needle roller conversion and fitted it. The engine was much quieter and smoother after the rebuild. It was still harsher and more clattery than a standard Redditch 500 Bullet, but also much livelier to boot.
After that full engine rebuild, it was time for yet another ride on this machine, probably in its best form in many years. Starting was as easy as you could wish for on such a machine, although it was best done with the magneto lever about halfway retarded and the Mk2 Amal’s enrichener on for nearly all except hot starts – there is no tickler on these carbs. Once running, the magneto lever could be moved to full advance and left there, unless a slow idle was required to impress bystanders or whatever else lights your candle.
The clutch was smooth, but heavy – a bit too heavy perhaps, but it worked without slip or drag and was actually one of the very few things I’d not improved in any way. (No one ever asked me to look at. So I didn’t!) In with the clutch and hook the gear lever up to engage first gear. Apply some revs and let the clutch out steadily. First gear is pretty tall, especially with a 22T / 46T sprocket combination, so some slipping of the clutch was needed to pull away smoothly.
The lighter than standard crank (but standard weight for a Fury) makes its presence felt straight away. You notice it even when just blipping the throttle in neutral, never mind when opening up in gear. The Fury gains speed much more rapidly than a standard machine, thanks also to the estimated 9:1 compression ratio and original factory ‘R’ cams. As I mentioned before, I’d retarded the inlet cam by a tooth to get the inlet valve shutting later to make kickstarting a little easier. This also boosts top end power and revs in some higher compression big singles, while sacrificing a small amount of bottom end grunt. On the Fury it is still possible to potter through the village at 30mph in top gear. Possible, but not ideal.
Back to riding: open up in first gear, pull in the heavy clutch, change up and open up again and repeat. Twice – there are four gears. This is another of those machines that can go up through the gears as fast as it will allow you to move your hands and right foot. However, you won’t be moving your appendages as fast as you might on some other machines, due to the nature of the clutch and selector mechanisms. These can be a nightmareg and totally spoil the Enfield
experience if poorly set up. Once correctly adjusted, they will behave decently enough.
The Fury’s acceleration is strong and once in top gear you can, by and large, control your speed just on the throttle alone and give your left hand a rest. Yes, the clutch on this machine could possibly be lighter and still work, but there are many out there with worse. Setting up an RE clutch could make an entire article on its own…
The overall feeling the Fury gave me was that of a slightly bigger, heavier version of (not surprisingly) a BSA B50MX. It may be more like a Gold Star Catalina but as I’ve not ridden one I can’t say for sure. The Enfield’s handling and brakes are good. The bike is quick and flickable, but I think you might get into trouble before those rather evil-looking folding footrests touched down. The rider of a modern, multi-cylinder machine was clearly getting agitated through the twisty stuff, when he realised I was gaining on him with the Fury!
The Enfield is quite a tall machine with an upright riding position, and wide and quite low handlebars. It’s reasonably comfortable and definitely fun. I never needed to fiddle with the steering damper, leaving it ‘off’ every time I rode the bike. With the gearing set to its later, higher form, keeping up with A-road traffic was a breeze. The odd stretch of dual carriageway or even motorway would be unlikely to faze the bike, although I doubt it would be much fun compared with blasting around more minor, rural routes. Town and city riding could quickly become a bit of a pain on such a machine, too.
Would I want to go far on a Fury? Probably not. The small fuel tank, which holds no more than a couple of gallons, combined with about 50mpg at ‘fun’ speeds, would be enough for me. By the time a refill would be required, I would want to get off and stretch my legs (and rest my left hand!) Short distance fun is where a bike like this scores best – and don’t forget to be home before dark!
Above: Royal Enfield understood as well as many manufacturers that a key to promotion was success in competition. Stripping back their road bikes and ra acing them proved the breed to be st trong and reliableL eft: The Fury. First spotted at the Telford d ShowS in 2010Right: The legendary Big Bear Run in n California started in 1921, when a co ouple of guys in a bar on New year’s Eve e decided to race the hundred miles fromA to Big Bear Lake. By the 1950s it had become a full-blown organised event, so o su uccessful that it was too large to handle e. The T final Big Bear was run in 1960 when a Fury took top honours, ahead of 764 other o motorcycles
Right: Although the Fury carries no lighting, the primary chaincase still has room for an alternator. Sparks are from a Lucas N1 magnetoBelow: At the heart of the Fury is a ‘big head’ Bullet engine. Its nickname is well-founded. Observe the serious carb and the neutral finder on the gearbox
It is one handsome machine, although we wonder whether a sports solo saddle might suit it better Left: The Fury’s 500 engine incorporated an enlarged inlet port, raised compression ratio and lighter flywheels, giving around 40bhp when paired to an Amal GP carb. Top speed was touted as being close to 100mph Below: Folding footrests are often a sign of competition intent, and can be hard to find today. Interesting concentric kickstart and gearchange shafts on the timing side, while the primary case shows signs of contact between the footrest hanger and the chaincase
What lies within. As well as the big head, there’s a pretty big piston, too The Fury’s frame design uses the engine as part of its structure, which has the advantage that it’s easy enough to remove
On any engine intended for actual use, the correct size and quality of bearings are always a good idea Observe an improvement: a Hitchcocks needle roller main bearing Paul reckons that the Fury’s engine should have replaced the stock alloy conrod with a steel item. The owner agreed, and it just so happens that Paul had one handy… RE primary chaincases may look familiar to Norton Commando pilots, with their single central bolt fixing and rubber band oil seal. Happily, Norton did not steal the occasionally eccentric RE clutch
All together now… Putting it all back together. If you look closely you can see both the needle timing side main bearing conversion and the steel conrod. Both are good ideas
To join Paul on his test ride of the Fury 500, hop over to this video on YouTube: https:// youtu.be/M_-IGyTV7Os After his road tests, Paul reckons the Fury is perfectly fine for shorter jaunts of up to a tankful of fuel. Oddly enough, that’s almost exactly the same distance as the Big Bear Race… Handsome…