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Royal Enfield Bullet 612cc - Part Two
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Andy C wanted a big Brit single and so he bought a Bullet. 500cc wasn't enough but 612cc might do the job. Part two; time to fire her up...

It was with some trepidation that I flooded the 32mm MK1 Amal, and applied power to the Boyer. This thing felt like it had massive compression, and a kick back could prove very painful - go on, keep reading…

From the first time I applied power and fuel to it, around two months elapsed before I had it running anything like OK. First of all I had battery problems. It was at this time that learned that Boyers do not like anything much less than the full battery voltage. I also had some bad earthing problems, and a connector in the wiring loom inexplicably came adrift. The thing had a kick like an aggressive mule, and it wrecked the starter motor sprag clutch such was the severity of the kickback.

When I did eventually get it running it was pinking like crazy - a combination of a battery earthing problem and timing. The battery earth problem was easily solved courtesy of a nice fat piece of wire and a couple of hefty solder on tags. The timing issue was resolved by scribing lines on the alternator rotor corresponding to TDC (for initial Boyer setting) and 28-deg BTDC for strobing, and a pointer was also fitted at the same time.

By then I'd spent more money than I care to think about (it's all well and good spending the cash on buying the 612 kit, but believe me you also need an uprated clutch). I was lucky to get my hands on a Bob Newby clutch from someone who bought one for a Bullet and lost interest. The Newby clutch is something like about 6lbs lighter than the standard clutch.

A potentially fire breathing beast, yesterday. Andy C's 612cc Royal Enfield Bullet

I now have this potentially fire breathing beast that I have lavished more money on that I care to think about. So what is it like to ride? Does it deliver the goods ?

The prospect of having to cover at least 1000 miles before I could really start to let her rip was not something that I relished. As we all know, it is at least 1000 miles of progressively increasing the power. During the first few hundred miles, there was not really a lot of difference, cruising at 50 or so with the occasional excursion to 60, but you could feel that that there was definitely something between your legs waiting to be unleashed (ooh-err missus).

It was not until around 500 miles or so I you could begin to appreciate what was on offer. It was when I found myself cruising effortlessly at 65mph that I realised it was a huge improvement over the 500.

At 1000 miles I was really starting to open her up. Anyone who rides a 'normal' Bullet will tell you that you do not usually contemplate overtaking a car travelling at 65mph. If you do then you usually have wait until you have a half a mile or so of clear road ahead, or a steep hill and pray (ok it's quite not that bad!). With the 612 you just do it because it's a whole different ball game. It has masses of poke in the mid-range, and it really does begin to sing at 70-plus, and despite it being a 612 single it just wants to rev. You can come up behind a car at 60 or 70, and simply open her up because it has the legs to pass with ease. At 70 it is straining to be let off the leash, and the engine is very smooth. It just wants to GO.

I cannot vouch for its ability to eat up motorway miles at 80mph as some owners have said, but would have thought that it may well be possible since the vibrations are not at all intrusive.

Say hello to PC Plod...

To date I have covered in excess of 1300 miles, and I have yet to fully open it up, and ride it really hard. I have seen around 85 on the electronic bicycle speedometer so far - the standard Indian one goes crazy at anything in excess of about 55.

I use Castrol Valvemaster in the fuel - but only for the octane gain as the head is compatible with unleaded, and I make conscious effort to avoid crappy supermarket fuel.

With the gearing that I am currently running, at peak power it would be pulling a theoretical 100mph, and I can see no reason why it should not be able to reach this, given the way it delivers its power . It would probably pull another tooth on the gearbox sprocket, which would equate to around 107mph at max power. Hitchcocks have put one of these bikes through a speed trap at a genuine 120mph (with a fairing). I have not been able to find a figure for max safe RPM for these engines, but looking at the Hitchcocks' dyno graph for one of these engines, power seems to dramatically fall off after 6000 RPM, so there is no point in revving it to beyond that. In the event of an over-enthusiastic right wrist, the Boyer is supposed to cut out at 7000 RPM.

So somewhere in the region of a genuine 100mph ought to be the top whack for this bike. Which is plenty as far as I am concerned.

The finished article

The only downside as far as the engine is concerned is that it will sometimes pink, but only at very low throttle openings, so it is nothing to be concerned about, just annoying.

When starting I have been recommended to switch the ignition on and give it two or three kicks before attempting to start it. This is because the Boyer (MK2; not the digital set-up) has a tendency to set itself to full advance when first switched on. Giving it a few kicks effectively re-sets it to the non-retarded state. It seems to work. Take it from me; if it kicks you it hurts - enough to make your foot ache for a couple of days. I know!

Now that timing and carburation have been sorted out, it never kicks back, providing you observe the starting procedures, ie kick it just over TDC and use the decompressor, then give it a full blooded kick. It usually starts second or third kick, and sometimes even first (but only when no one is looking).

If you ever consider doing this sort of thing to your Bullet, then don't do it without uprating the brakes and suspension as well. I have fitted the Hitchcocks uprated front brake cable and shoes - a huge improvement, but still could be better.

Likewise fit the softer fork springs, and either Hagon rear shocks or softer rear springs. Without these mods it is nothing like as much fun mainly because the standard Bullet suspension is so hard, and the brakes so poor.

What for the future then?

I have yet to really wring its neck -- I haven't needed to so far. I may well consider fitting a front disc conversion, or even a completely different front end with some really good braking, or just see what I can do to improve the front brake. And there are already some cosmetic mods in the pipeline. Oh yes and there is that sprag clutch to fix. And that five-speed gearbox is tempting…

Random Bullet stuff on

Royal Enfield Bullet Electra Clubman

*An Alternative
It may not be considered to be as authentic as earlier Bullets, but the current model Electra-X 500 comes with electric start, a five-speed gearbox, uprated brakes and about 30bhp when fitted with the straightforward highway kit. In Clubman trim with the Highway kit fitted, a brand new one costs around £4895.

More photos and details of Hitchcock's conversions are at www.hitchcocksmotor


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