Electricity, phases and wiring harness

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Jul 18, 2004
Hi Guys,

I have spent weeks/months occasionally pouring over the wiring diagrams, translating the squiggles on paper to the reality of the multi-headed snake lying on my floor that I received in the mail- I think I have it figured out.

For the record, my set-up (pile o' parts) is:
  • Sparx 3 phase alternator
    Sparx regulator
    Boyer Mk III
    Mark II harness (Andover)
    Halogen headlight
    2 PVL 6v coils
    Autolite plugs & resistor caps
    (after the forum convinced me) a battery.
I won't be using the rectifier and zener.

Question # 1 (warm-up question)
Is the purpose of the capacitor just for starting with a dead(ish) battery?

Question #2
Is the green/yellow lead the same voltage/current as the original single phase alt?
I want to connect the warning light assimilator - can I connect the green/yellow lead from the alternator to the assimilator, as it was originally done?

I sent an email to Sparx for question #2 ( I will share the answer with you if/when I get one) but I thought someone here might know the answer . :wink:

Many thanks,
Hi Phil,

Yup, the cap is just for starting with a deadish battery. Don't know if it would work with the Boyer though. I think there was a thread discussing that a while ago but I don't remember what the consensus was.

I'd think one phase from your Sparx would be sufficient to drive the assimilator but of course that's just my supposition. I'd wait for the experts at Sparx to answer your question before hooking it up! :wink:

So when's that bike gonna hit the road? :)

When I did a similar swap with a Lucas three phase stator and Podtronics regulator/rectifier, the assimilator can would not work. I got a solid state cube from RGM which simply lights the warning light when the voltage going to the battery is less than 12 or more than 14. Alternatively, you could use an ammeter.
With the Mark Three Boyer ( not micro digital) you woun't be needing or wanting the resistor caps save them for going to the next stage Mico digital Boyer. The cap just fills in the low ebbs of the AC output making the DC that the bike uses a little more consistant. They can't start a bike but they help it run better if they are the right size. Too small can't help too big drains the Boyer power from the battery. norbsa

as ron said the stock assimilator WILL NOT WORK the output will toast the thing DAHIK I have not tryed the RGM part but a friend made the same thing for me before we found the RGM part. it is basicly a comparator switch that turns off the warning light at a set voltage.

sparx: guess I shouldn't comment when I don't know what I'm talking about! :oops:

capacitor: my bike WILL start with no battery, just the original blue capacitor. I haven't tried starting with both battery and capacitor disconnected. I've been told that won't work but who knows? I have points, not boyer. Sounds like it doesn't work for the boyer - too much current drain from the electronics?

My bike will be on the road as soon as I solve the work/time/money equation. My Norton project has become something of a running joke with friends and family ( or should I say a non-running joke?).:oops:

Thanks for the heads-up on the assimilator. Mine is new from Andover - looks like a circuit board glued into a film canister... I emailed them and this is his response:
Yes, it's solid-state. The original Lucas one has a thermo-mechanical switch inside which is prone to self-destruction.
Lucas no longer makes them so we commissioned our own.
You are saying the resistor caps smooth out the AC to the plug, that I understand.
I am confused about the rest, (probably because of my rudimentary understanding of electrics). I was under the impression the resistor cap was to suppress interference to keep the Boyer happy (that's a technical term). Now that brings me to the question of interference. Interference from what? The alternator? the environment? and why don't I need / want that suppressed with the Mark III.
Using resistor plugs/caps/wires certainly won't hurt - correct?

Thanks again.
Sparx says their electronic regulator/rectifier requires resisted spark plugs (caps or plugs) otherwise it can overcharge the battery. I'm not savvy enough in the ways of electronics to understand why.
Thanks Bill, neither am I, but I knew there was a reason I bought resistor caps in the first place!

Yes, it seems resistor plugs have many magical properties. :lol:

Suppress frequencies:
At the moment the spark jumps the gap it causes a high frequency burst of energy, this is known as RFI (radio frequency interference). This is why resistor spark plugs were introduces in the mid 1960's. Placing a resistor within the spark plug suppresses the RFI. Without resistor plugs in your bike the plug can interfere with the bikes ignition.
Prevent electrode erosion:
Plugs with an electrical resistor located inside the insulator have been on the market for many years. Their original purpose was to get a better idle. Engines idle smoother with wide plug gaps, but without resistance, metal rapidly erodes off the plug electrodes, quickly resulting in gaps so wide the car won’t run.
Compensate for bad jetting:
...I have found that using Bosch's platinum plug design will get you past some marginal jetting so that you can actually run the bike enough to make necessary jetting adjustments. Also, they are a resistor plug. So you don't need to use resistor caps. These are not to be trusted in my book.
Save your battery
When using SPARX regulator rectifiers you must use resisted spark plugs as circuitry is sensitive. Using unresisted plugs can cause over charging.

Now if only they could make my whites whiter.... :wink:
If you don't need both caps and resistor plugs just run the plugs with standard caps. The resistor caps take away fire power from the ing. system. The blue can cap. has to do with the supply side of the whole system . norbsa
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