Triumph unit twin rebuild
In the Chuck Berry song Promised Land, the poor boy is desperate to reach the terminal zone, yet events conspire to prevent this nirvana being reached.
In this project, my version of Chuck’s promised land isn’t the terminal zone of a California airport, but rather the electrical charge which the alternator is putting out reaching the end of the line… or the electrodes at the end of the sparking plugs. Like the autobiographical ‘poor boy’ of the song, the journey is thwarted at every turn and the hero bemoans his struggle.
This is where the similarities end though – I reckon old Chuck’s tale topped up his bank account a bit, whereas my tale promises to empty mine a little.
One of the major stumbling blocks in my way is I find electrics a mystery and I’ve had extremely well qualified electricians try and talk me through how easy it is and plenty of suggestions from TCM readers offering their solutions to the issue.
Actually, there’s another stumbling block along the way, in that I’m trying to use the bits I have in my workshop to prove a point. Ideally, there would be a chance to have said well-qualified electrical mates along to point out where I was going wrong. This is what happened many years ago when struggling to keep lights working on my 650 Triumph. In those days, my mate Tony – Tony Geddes, a Moto Guzzi enthusiast – popped along one afternoon and plugged in his box of tricks and sussed out where I’d been going wrong. A few hours later, the wiring was sorted and for the next few years the worst electrical problem was a popped headlamp bulb… Okay, this was at night on the Route Nationale heading for the ferry at Calais, so it was interesting, but changing the bulb sorted it again for a considerable length of time.
This led me into a false sense of security and convinced me I was if not an electrical expert, then perhaps had attained a level of competence. Yes, deluded I know. If this were a normal time, I’d have been at a number of shows over the past few months and would have sorted the problem, but as we’re well aware this isn’t a normal time, lockdown may be easing but we’re not quite at the free and easy point yet where we can meet up and discuss things like which wire goes where on what component and do I really need a capacitor as well as the powerbox. It’s all well and good saying ‘ask someone,’ but this is no substitute for seeing something in front of you, or at least it’s not for people like me.
Nor is it helped by my lack of knowledge of exactly what I need for this wiring; the 650 was easy, magneto ignition kept the wiring simple and I only needed the lights. For this project, the electrics need to produce the spark too. The original wiring diagrams are all full of switches and relays and such things, and seem awfully, tediously complicated.
As this machine will see a little off-road action as well as some normal tarmac work, I have set views on what I don’t want on the bike… a battery. I’ve managed for the best part of 30 years without a battery on my 650, the lights – when fitted – come on and stay on, which is the idyll for this 350 too.
Triumph dallied with a distributor when they unitised the small twins and this is what’s fitted to my engine, it’s been stripped, cleaned, reassembled and turns nicely as the kick-start is pressed. The alternator is a three-wire Lucas RM19 – I think – which would have originally produced 6v but connecting two of the wires together allows the thing to supply 12v and all the info I can find tells me this is a better situation.
In the original system, power arrives at the rectifier from the alternator, this magically goes on to the ignition coil from where it goes to the distributor to feed the contact breaker. There is also a high tension cable from the centre of the coil to the centre of the distributor cap and this feeds either spark plug.
According to all my information, what I have should work, I conclude from this I’m: a) missing something vital; b) the components are not working, or, c) a combination of the two. It doesn’t help either when trying to explain to suppliers I’m not wanting to have an original system, and when talking to fellow off-roaders the answer is simple ‘fit an electronic ignition!’ as though I’d not thought of this already.
Like most people, I don’t have unlimited funds to chuck at the bike – there’s a few other machines in the garage also needing attention – and the helpful comments of ‘what are you mucking around with a distributor for?’ sort of miss the point.
Some years ago on my own magazine – Classic Dirt Bike – we rebuilt a Can-Am enduro bike and needed ignition and lights for this bike too. Back then, we contacted Ferret’s Custom Electrickery and after a day with switches, wires, terminals and tea, a reliable and waterproof electrical system was devised and this sounds like a sensible way forward to me… at least, it does once Covid is beaten and we have some normality again. Meantime, I have a lot of wires, a lot of components, a box full of terminals and a lot of frustration...
Nor is the oil tank back from the welder’s yet. It went off ages ago and the lockdown caused a delay there. Still, it’s not snowing, there have been dry days and motorcycling looks like it will restart soon. Perhaps I could write a hit rock ’n’ roll song about this journey… I doubt it would fill my coffers with restoration tokens though…