Upgrading Commando Electrics

Iam thinking of upgrading the original stock alternator on my 1973 750 to keep pace with 60w halogen headlight that I have fitted. I have already fitted a relay . There is a Sparx Hi Output Alternator Kit available that replaces the stock stator, rotor, regulator and zener. Claimed output is 210 watts and is said to put out 10 amps at 2000rpm. I would be interested to hear opinions from forum members on this Sparx kit. At this stage Iam still running the stock iginition- points etc.

So far as upgrading the ignition the choices seem to be- Boyer, Tri SParke and Pazon. If I go down the Sparx alternator route, what is the recommended electronic iginition system?

All comments will be appreciated.


Bazz


1970 Triumph T120R
1973 Commando 750 Roadster
1979 BMW R100S
1993 Harley Wideglide

I've installed Sparx systems on 2 Commandos and they work very well. Highly recommended. It will not limit your choice of ignitions. I have a Tri Spark on mine, my brother has an old Boyer and both are happy with the clean power.

Unless your rotor is defective, a high output stator and a 200w Pedtronic Rec./Reg (or any of the like) will bring it up to speed.
I have had the Boyer, Sparks, and Pason ignition systems. I have found the the Boyer is standard. The sparks unit control box went bad and even though Old Britts did not sell me the unit, he sold me a box out of a kit to replace. The Pazon I now run and is simple clean and above standard. These can be purchased directly from Pazon in New Zeeland at a fair savings. It is already priced very competitive. Nice people IMO. At came clear around the world in a week.
The TriSparp seems to be the Cadillac with the Cadillac price. My feel about the Tri is it is a (somewhat) self contained unit and if it goes bad (and they all can) it goes really bad. Although costomer service good I'd rather not go there. I almost buy 3 Pazon for one TriSpark.

Bazz said:

Iam thinking of upgrading the original stock alternator on my 1973 750 to keep pace with 60w halogen headlight that I have fitted. I have already fitted a relay . There is a Sparx Hi Output Alternator Kit available that replaces the stock stator, rotor, regulator and zener. Claimed output is 210 watts and is said to put out 10 amps at 2000rpm. I would be interested to hear opinions from forum members on this Sparx kit. At this stage Iam still running the stock iginition- points etc.

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I have the SPARX 3-phase, high-output alternator on several old British bikes and they work great. You may need to open up some of the mounting holes and fiddle with it a bit to get the required air gap all the way around when you mount it up. Having sufficient gap (0.010) is absolutely critical. On my Commando, I have the SPARX single-phase, 180W alternator and it also keeps my battery charged with no problem. A bit cheaper than the three-phase. The major advantage of the three-phase is that it puts out higher amps at lower engine rpm. For the kind of riding I do (very little stop-and-go city riding, no electrical accessories, standard headlight) the single-phase is all I need. As pvisseriii mentions, you will also want to get a solid state voltage regulator and that needs to be matched to the alternator. I think the SPARX kit you mentions has a regulator/rectifier in it correct?

I use Boyer ignitions and they have always performed perfectly for me

I'm repeating below the remarks I made last July on the charging capacity of my SPARX 3-Phase alternator on my rebuilt Mk3:

Returning from a lovely ride this morning in brilliant Pacific Northwest sunshine, I did a quick test of the battery voltage (dc) as a function of engine speed. I'm running an 18 A-H Yuasa, one year old, and SPARX 3-phase alternator and rectifier/regulator. Standard filament headlight. Pazon Surefire (ignition consumes 20 Watts or so).

Column 1:Speed (rpm)
Column 2:Voltage (vdc)-no lights, ignition only
Column 3:Voltage (vdc)-lo beam
Column 4:Voltage (vdc)-hi beam

0000 12.50 12.30 12.30 (ignition off)
1000 12.35 12.15 12.10
1500 12.40 12.25 12.20
2000 12.80 12.60 12.50
2500 13.40 13.00 13.00
3000 14.00 13.20 13.20

With this unit I get positive charging at all speeds above 1800 rpm with my lights on. I believe that the SPARX specs are accurate. At normal operating speeds around town, you'll have no problem running your halogen light and staying fully charged.

While it's strictly true that you can replace only the stator of your present alternator, the rotor demagnetizes over time. If your present unit has some age on it, you'll get better performance by replacing both the stator and the rotor.

With Sparkx 3 phase stator, factory rotor and Podtronics 3 phase 200 watt rec/reg >
At one time I ran 170 watts of headlight and driving lights, creeping in dark up crocked drive way freaked to miss a passing deer cluster before I could stop or hit one on purpose head on instead of knock down sides ways. The LED volt meter turned green ~1800 rpm in first, which was a bit faster than I wanted to ride those conditions, so had to give up the driving lights, but main bad choice of type and placement so too much glare back. Need pencil beams instead. Sparx kit is not quite enough to run in stop go traffic with lo beam unless constantly de-clutching to blip up or sit in N over 14-1500 rpm. Fortunately that don't heat up a Norton much compared to hwy 60 mph cruise. Its more a fuel thing than air flow factor going slow.

What we really need is super magnet rotor - then even stock 120 watt stator would likely double in output.