The problem here is mating a Chief engine to a Triumph clutch, as the Springfield engine sprockets and Meriden clutch chainwheels use different chain sizes (Triumph is British Standard 3/8in.). Chief engine sprockets are also a lot smaller than Triumph ones (24 and 29 teeth respectively) so gearing ratios become an issue.

I then need to enclose it all in a suitable chaincase, given that I may well end up with a unique distance between shaft centres. This means there may be no chaincases already made that will fit, or (more to the point) look good. I may have to get one cast up as a one-off, and I'll talk more about that in a future column. Kevin Lowe, on the other hand, says he will weld one up for his bike using stainless steel.
 

If you've been farting about with engine mounts, trying to get engine and clutch sprockets to line up yet still get a chain through to the rear wheel, then this type of construction for an engine sprocket gives you a few extra millimetres to play with either way. You can use a press to slide the inner Chief portion further in or further out relative to the Triumph portion, until primary chain alignment is perfect.

The use of Triumph parts for the entire drive-train from the engine sprocket right back to the rear wheel also solves any headaches that might arise with gearing ratios. Effectively, the bike will be geared like a stock Triumph, and this gearing can be altered just as you would with a stock Triumph. Though it's helpful to decide ahead of time how many teeth you want on the engine sprocket, given that each has to be made up as a one-off "special".
 

Of course it will. Think about it! Springfield may have bragged about its four-row chain to handle all that grunt, but they sneakily removed one row of teeth from the clutch basket so's they could make room for a generator drive. This means that Chiefs effectively have a three-row primary chain. Moen thinks even my three-row Triumph chain is overkill, and sez I could have gotten away with using the two-row set-up found on my 350-cc T90 engine. The Von Gill Mongrel uses the single-row chain of pre-unit Triumphs, though he hasn't done enough miles yet to find out how long it lasts.

Generator/alternator drive

To me, one of the attractions of using a non-Springfield primary drive and transmission was that I could lose that silly generator drive that Chiefs have. It really looks like an afterthought, like they forgot to design the bike with a generator and had to tack one on at the last minute.

There's lots of other ways to put a charging system on a Chief. Running a generator at the front of the engine Harley-style with drive from the magneto gears is one way to do it. This is not without its problems, though. Magnetos turn at half the engine speed, and a generator would here do likewise. Someone also told me (don’t know if its true or not) that the Chief magneto gears may be lighter in construction than Harley generator gears, as magnetos impose less of a load than a generator.

Moen is fond of stringing v-belts or chains all over the place, from behind the engine sprocket to a generator forward of the motor like on Scouts, or up high in front like on a Velocette, or behind the motor like on Matchless and AJS single-bangers. Me, I want my engine to end up looking cleaner, not messier still. Unless seeing the "works" of a generator drive in action is all part of the appeal of one's project. Beauty is in the eye of the beholder. I for one want my charging system to be out of sight. Don't want any garbage obscuring my view of that handsome Chief engine.
 

Being an already Triumph-oriented person with a pile of parts still remaining from the Thunderbird rebuild, I began looking at Lucas alternators with renewed interest. Triumph was an industry leader in pioneering alternator electrics during the early fifties, when everybody else adhered to generators. Edward Turner was attracted to their simplicity and the lack of wearing parts, and, knowing him, their price. It took a few years before the theoretical advantages became actual advantages, but that was only because of his lame-brained idea to cut costs further by having the charging system wired through the lights rather than fit a regulator. With the lights off, only one set of alternator coils was in the circuit. Turning on the lights simultaneously switched in another two sets of coils. Once dear Edward finally decided to shell out a few extra shekels for a zener diode and heatsink, the system became pretty reliable notwithstanding Joe Lucas' "Prince of Darkness" reputation. The one on my Triumph hasn't let me down, and it can be used to run either 6V or 12V electrics (mine is 12V).
 

First, the stator. Holding a stator up to the Chief left crankcase main-bearing boss revealed one of nature's minor miracles. The three holes in the bosses' flange for the three inner-primary retaining bolts are as-near-as-dammit on the same centres as those drilled through the Lucas stator for its three mounting studs. Theologians would regard this as one of the proofs that there is a God.

It means that the stator could be mounted to a Chief just as on a Triumph. All I have to do is get a machinist to make me a set of stator mounting studs that have Triumph dimensions on their outboard end, and Indian dimensions on the inboard end where they double as inner-primary retaining bolts. Neither the Chief cases nor the Lucas stator require any modification.

BSA, and also Triumph for a couple of years, use another stator mounting system. This employs a cast alloy basket to support the stator. It sits inside the primary case and bolts to the inner primary, with two slots in its side for the primary chain to pass through. One of these from a BSA C11 is illustrated, to show you how it works. Personally, I think I'll go for the three studs, as these are easier to make and take up less room in the primary case (which I want to be a slim as possible).

And now, the rotor.
 

This has really got to be done properly, as any slight wobble or vibration will probably snap the mainshaft threads like a carrot. It is not beyond the bounds of possibility, though, and Rohan Bradney tells me it's been done before. He once had pass through his hands a Royal Enfield twin that had been converted from dynamo to alternator electrics using just such an "extended nut".

Moen's fertile imagination has come up with another solution to this rotor problem when using the tapered type of mainshaft. He proposes mounting the rotor remotely from the mainshaft, in its own bearings in the outer primary, but somehow engaging with the engine sprocket for its drive. 

This idea, requiring only the casting of a special outer (and possibly inner) primary and the addition of a coupling between rotor and engine sprocket, could be developed into a bolt-on 12-V alternator kit for otherwise stock Chiefs. The only external clue would be a bulge in the outer primary similar to that for the torque-evener mechanism, but wider in diameter. Just remember - you read about it here first, in the Virtual Indian magazine!
 

Once it was in my hot little hands, this shaft revealed both a solution and another problem. The solution can be found in the fact that the existing hole through the middle of a Lucas rotor is about half the width of a fanny-hair away from being a snug fit on the outer portion of an 80-in. Chief mainshaft. Trying five or six different rotors revealed fits varying from sloppy to "almost-snug". Machining out the middle of the rotor a tad to accept a pressed-in steel bush of the correct i.d. will soon fix that up. In terms of length, there is ample room on these shafts to fit both engine sprocket and alternator rotor, with enough thread left poking out to get the mainshaft nut on.

At the time of writing, only Starklite sell these quills, and they charge $175 each for them. 

Yeeoouchhhh!

Moen also mentioned a potential problem with Lucas rotors, which bears repeating here. The magnets embedded in them place a lot of mass, and hence momentum, at the outer circumference, yet their drive is from the middle. It is not unknown for the aluminium-alloy outer part to come adrift from the central steel sleeve that is keyed to the mainshaft. Lucas eventually fixed the problem by welding in the centres, but there can apparently be a fair few rotors out there with dodgy centres.

The drive to the rotor can come instead from studs screwed into the two threaded holes in Triumph sprockets that were intended for the special Factory sprocket-puller that nobody ever uses for Triumph sprocket removal. These studs will fit into two holes that you have judiciously drilled in the rotor. This places the rotor drive further out toward the circumference, and your middle bit will never shear again as its only function now is to hold the rotor concentric on the shaft. Neat, eh!
 

As you can see, and despite my attempt to write about them under separate headings, the issues of primary drive and generator/alternator drive had to be dealt with holistically. My decision to use a crank-end alternator largely determined the decision about how to construct the engine sprocket. A one-piece mainshaft holding both sprocket and rotor has got to be stronger than a two-piece shaft where the rotor is mounted on an "extended nut". The "extended nut" idea can be made to work, as Rohan will attest. It will appeal to people who don't want to tear down their engine and rebuild it with a torque-evener mainshaft before they're able to proceed with alternator electrics. Moen's remotely-mounted rotor idea is also attractive in this regard.

Because my own engine is still at the stage of being spread out over an area the size of a tennis court, I am at liberty to decide which type of driveside mainshaft I want to use. Accordingly, I have recently ordered a brand-new 80-in. Chief splined mainshaft from Starks for the princely sum of $114. My 74-in. Chief tapered-end shaft by Jim's is now surplus to requirements.

Anybody out there want to swap it for a torque-evener quill?