CLASSIC TECHNIQUES
Last month, Stephen Herbert set about proving that five into four does go, by replacing his Enfield 350’s old Albion 4-speed gearbox with a more modern 5-speed set-up. This time he explains why, and what it’s now like to ride…
The only suitable word to describe the Enfield now is MOST EXCELLENT. OK, I know that’s two words, but EXCELLENT on its own doesn’t seem enough. But before I explain why it is now so described, let’s wind the clock back. Why did I do this? When I first rebuilt Rusty a couple of years ago (when Rusty was truly rusty), one thing I didn’t strip and rebuild was the gearbox. ‘What could possibly be wrong with a 1993, relatively new gearbox from India with less than 9000 miles under its belt?’ I remember saying to myself.
The answer, it seems, it quite a lot. I spent a lot of time commissioning Rusty with his super-fast tuned engine (bigger carb, gasflowed head, alloy barrel, higher compression piston, free-flow exhaust, go-faster stripes), and initially the odd false neutral and/or missed gear seemed unimportant. It was only when I started to use Rusty in earnest on club runs (see VMCCcheshirecats.co.uk for more) that Rusty’s gearbox woes truly surfaced.
For instance, there were a lot of extra neutrals in the box. Don’t know where they were, I opened it up a few times but couldn’t find them lurking in the greasy depths. Sometimes these false neutrals were in one place, other times elsewhere. It was like the bike was trying to outwit me (successfully!). On some runs I was worried about disaster striking if I couldn’t find the right gear when approaching a steep hairpin on the Horseshoe Pass. Eek.
I did try to fix the box by doing all the obvious things like adjusting the clutch, detent plunger, selectors (such as they are), etc, but to no avail. There are technical pages on these techniques posted on Hitchcock’s interwebthingy if you too are struggling.
Turn the clock back even further and we discover that the cogs in the original Albion box – upon which that this Indian one is based – have seen service in many guises from industrial lathes through small capacity bikes to the mighty Interceptor. It’s a very old and fairly crude design, particularly with regard to the selector mechanism, so I suppose we shouldn’t be surprised that it
struggles in the 21st century. However, my Constellation has a similar box and it’s sweet as a nut. Any ideas?
In the late 1990s, RE commissioned a new, 5-speed box for its future models (Bullet 65, Electra-X, etc). I had an Electra-X a while ago and a very good box it was too. Still not a Japanese gearbox, but the selector system uses a proper camplate instead of matching soup spoons and forks so is a massive improvement on the old Albion one. Most of these boxes were installed on Enfields with left-change, 1-down and 4-up configuration but are easily modified to right change with the configuration either the right way up or upside-down, depending on your point of view. This was exactly what mine was. I sourced it as a secondhand item from Hitchcocks with an upside-down (to me) 1-down and 4-up mechanism.
BEING RATIONAL ABOUT RATIOS
I promised not to get into too much math, but it’s worth having a look at some numbers. These are the gear ratios of the two boxes:
I don’t find these tables of gear ratios particularly helpful, as they’re just numbers and my brain finds it difficult to draw comparisons. If you draw the numbers as a graph, you get this: ( Top Graph)
This actually shows what’s going on. ‘ Top’ is the same on both (1:1) and you can see that, for example, first on the 5-speeder is slightly lower than first on the 4-speeder. Fourth on the 5-speeder is between third and top on the 4-speeder. But this doesn’t show what Rusty is truly doing, because I’ve fitted a larger (17T) gearbox sprocket which naturally affects the overall ratios. With me so far?
The true effects of the 17T sprocket on the comparison between the boxes looks like this: (Below Graph)
This shows that first and second on both boxes are effectively very similar. Top on the 5-speeder is a bit higher than on the 4-speeder, and third and fourth on the 5-speeder are well spaced between these other ratios. This (the well-spaced ratios) is exactly what it feels like when riding Rusty. A cog for all seasons!
TAKEN FOR A RIDE
So how does it ride? As hinted earlier, MOST EXCELLENTLY! The 5-speed gearbox snicks quietly into first without any alarming clanging and banging. It’s even possible to select neutral at a standstill, which I could never achieve with the old box. Smooth, predictable, plenty of feel, no slipping or dragging of clutch. No false neutrals whatsoever.
The pedal movement is slightly ‘longer’ than on the Albion box, but that’s not a Bad Thing, as it lets you know it’s doing what is should be doing. My memory is hazy, and I sold the Electra-X with the same 5-speeder a while ago, but I think this box is better than the Electra-X one. This is possibly because the Electra-X had left-foot change, which worked via a long spindly rod passing through the oil tank and primary chaincase to the pedal, or possibly because of the excellent Henry Price 5-plate clutch conversion fitted to Rusty.
I’m really glad I upped the gearbox sprocket size too, because the overall ratios on this set-up seem near-perfect. Fifth certainly feels a little taller than the old 4-speeder due to the 6.25% uplift, but it doesn’t create a problem as the gap down to fourth isn’t too wide. As the change is predictable and easy it makes it easy to change down. All the gears seem to be ‘right’ – certainly for my kind of riding. They probably wouldn’t work well if I were racing Rusty at Oulton Park,
but I wouldn’t let him loose on the circuit in case he damaged himself. RE Bullets aren’t racers… but the ‘Bullet Whisperer’, Paul Henshaw, might disagree with that statement!
Somehow, whether real or imagined, Rusty seems to go better with the 5-speed box. I don’t know if this is because the new gear ratios suit the mildly-tuned 350 engine, or perhaps it’s reduced internal friction, or simply because the box changes properly when I want it to. Maybe it’s zen or something supernatural. I don’t know, but the bike feels positively transformed. That might suggest that Rusty was unpleasant to ride before his transformation. This would be incorrect. I always enjoyed riding him, but gearchanges were a bit of a challenge and created some nervousness when approaching obstacles which necessitated precision in the box department. Now that Rusty’s changes are entirely predictable and without drama, he’s much better.
The only slight issue I still have is the ‘upside-down’ change. I was brought up on an RE Crusader back in the day, with a 1-up and 3-down configuration. Rusty now has the opposite and the first ride was ‘interesting’, to say the least. I have started repeating the mantra ‘up means up and down means down’, which seems to help…
FINAL FETTLING
A couple of things needed doing after that first, tentative ride to make sure everything else worked OK. These were chain and electrics related. During the gearbox transplant, it became apparent that by fitting a 17T sprocket to the gearbox output shaft, I needed a slightly longer chain, as there was no adjustment left on the wheel / swinging arm. No problem. Those friendly guys at Hitchcocks supplied a 95 link chain the very next day.
The first thing I noticed on the road was that there was a bit of a scratchy / rattly noise coming from the dark places somewhere underneath. This seemed to vary in intensity as I went over bumps and when accelerating / decelerating. It didn’t take long to realise that the chain was just rubbing on the locknut at the back of the brake pedal hanger. Maybe this had been happening all along, although the witness marks on the new chain suggested not. Maybe it was a result of a very small difference in the axial position of the gearbox sprocket on the new box. Trouble was, the locknut played an important role in stopping the brake pedal pivot unscrewing itself so couldn’t simply be removed.
After a bit of head-scratching, I worked out that I could move the locknut outboard and still have the same function. The chain had a free run and the marginally outboard position of the brake pedal didn’t seem to matter. The scratchy noise definitely disappeared.
The other thing I wanted to do was to make use of the neutral switch on the new box. It’s really useful on my Beemer, so why not connect it up on Rusty? Noted Enfield Experts will know that the original 4-speed Albion box has a neat trick in the form of a neutral finder. This is a simple extra gear lever which, when stamped on, puts the box in neutral. The 5-speeder has none of this nonsense, so that neutral switch to an instrument light is a must.
All I had to do was to run a wire from the terminal on the switch on the back of the gearbox to an idiot light somewhere on the dashboard, and from the other side of the idiot light to the ammeter for power. Very easy to do, slightly naff idiot-light siting, but it all worked perfectly. I may tidy this up at some point in the future – and/or add a main beam idiot light as Rusty doesn’t have one.
But this created another potential problem. Due to the position of the neutral switch at the back of the gearbox, it was vulnerable to spray off the rear tyre. Rusty, like all Indian Bullets, has a mudguard extension which sits in between the toolboxes, but it doesn’t extend down low enough to protect the neutral switch. Having made up a new bracket to secure the bottom of the mudguard extension during the transplant, I simply made a mudguard extension extension out of thin ally sheet and secured it to that bracket.
After all that, Rusty now has a fully functioning gearbox which inspires confidence and tells me when it’s in neutral. As a result, the Enfield has become my favourite bimbling bike. I use it for most of our club rides now, and the Bullet is even old enough to be VMCC eligible. I can thoroughly recommend this transplant / conversion for any Bullet with a dodgy (or even otherwise) gearbox. Snag is the 5-speeders don’t come on the secondhand market very often – I was lucky to phone Hitchcocks just as they were preparing this one for sale. They do, however, appear new on eBay from Indian vendors, and most come with a matching clutch, so you could take a chance with one of these if you feel brave!
Now, would anyone like to buy a 4-speed Indian Bullet gearbox? One careful owner. No? Oh well, suit yourself!