SF electrical conversion

[Fitz]

Just mulling things over while I have a coffee. Has anyone ever converted an SF to use an alternator charging system. My extensive rebuild of my SF1 has a number of mods and it seems like it may be worthwhile changing from the original dynamo to an alternator, simpler, more efficient, fewer compoenets to go wrong. Just wondered if anyone has done it before

 

[Rob]

As you might expect, one or two of our number have been there and done that ....

https://laverdaforum.com/xf/threads/103022/

 

[Paul Marx]

Plenty of 750s with belt driven alternators out there.
It's more parts, not less. You need a regulator.
Nothing simpler than a dynamo and an excellent output.

You'll be putting electronic ignition and relays on it next. Why make a simple machine complex?

Paul

 

[Ernesto]

"Why make a simple machine complex?"

Paul hit it!
There are 2 wires going from the dynamo to the regulator and that's it.
The dynamo is basically the same as in VW Beetles and a lot of tractors.
And the supply is sufficient for our 750s.

The Kuwaitian Police bikes had alternators. BUT: they needed a higher
supply because of sirens, police flashlights and most likely radiocom (?).

Ernesto

 

[piranha-bro2]

ND alternator from a GPZ/GPX 900/1100 Kawasaki running via a Gates toothed belt running at 1.75x crank speed - two wires to the battery (reg/rec inside the alternator). Lighter than a dynamo, produces power at idle, allows fitment of a much smaller battery. Very tidy fit. Not a small amount of work involved but nothing crazy. PM me if you want pics.

I agree the Bosch genny and reg is a ripper but I am just into mods and upgrades.

 

[CLEMTOG]

always remember that the Kuwaiti police 750's that were fitted with alternators had a much longer belt drive cover, comsequently they are a rare item, but you never know, a lot of those bikes imported to the UK were "scrappers" and an alternator with bracket, pulley and the long cover cou;ld be obntained if luck ewas on your side.
Personally I see the dynamo as being big enough to run everything on a car, so I never did see the need for the cops to have the alternator.

I have seen alternator conversions on triples (back in the puny days) which used units from microlight aircraft (very small and light) and I have noticed that the alternator on my Kubota mini digger looks much the same.
CLEM

 

[piranha-bro2]

Auto elec who advised me on wiring and direction of rotation (apparently doesn't matter) said the ND alternator I used was also a common fit for ultralights.

 

[iis_iis]

Having access to automotive engineering at my college, tested one of Martins SF DC dynamo ( bosch i think ), on a fit for purpose testing jig, had better performance than the motorcycle Permanent Magnet alternators of the day. May have been close to or better than 300Watts. Low rpm output was not super good, though being a direct DC output it had no losses in the electrical output. As mentioned here by others, why change it, fit for purpose when maintained and correct adjustments on the regulator can ( relay adjustment is perfect for sympathetic to electrics mechanics )..... my perspective....j.

 

[Tippie]

My SF generator put out 22 amps on a test bench. The marine elec said that the only difference he could see from a 22 amp VW one was that the car one had holes open at the end for cooling air.

 

[iis_iis]

Good to have specialised equipment available, Tippie. 22amps at above 14V higher rpm is good, no question. Hard to imagine an older Laverda needing more than that. Apart from lighting, the next notable power device would be the ignition on points. Many advantages to points, alas power efficiency is not one. j

 

[chrisk]

Mine has a Kobuta alternator. Picture coming.

 

[Fitz]

Mine has a Kobuta alternator. Picture coming.

Never saw any further action from your post in 22, did you ever get around to providing details. The main reason for updating things is that due to lack of crucial parts like sppedo drives and worm gear that are mashed on my SF, I have a digital speedo and very neat rear light built in brake light, hazard lights, all manner of nonsense. To use a digital speedo would require a modern electricla system, simplicity is not in question but using an alternator eliminates the regulator etc as its built into the machine, modern lightweight battery a possibility

 

[LaverdaSoren]

When I have built my special I have used different new parts just like You Fitz. Electronic tacho, LED-lights, Ignitech ignition and a Kubota dynamo. The Kubota dynamo is efficient and has lower weight then the old VW-dynamo. The size of the dynamo pulley makes the gearing almost the same as for the original. The voltmeter on my Motogadget tacho is showing 12,5V at 800 rpm rising to 14,5V at 3000 rpm and staying at about 14,5V at higher revs. I have not measured any Amps but after about 700 km my 10 Ah battery still has the same voltage.

 

[motoddrob]

That's a neat job

 

[piranha-bro2]

Smaller and tidier than mine, although with the cover on mine looks very compact - ND unit, cranks out loads of power, no reg/rec required.

 

[Tippie]

One heavily modified nice SF you have there Søren.