SF1 Regulator Issues

C

chrissoz

Senior member
Location
Sydney, Australia
Finally have my SF1 back together and it is looks good.

Full rebuild including all new electrics based on M-Unit - new coils, new regulator etc.

Runs well - still some carb tuning to do and sorting out other small issues.

Biggest problem so far is lack of charging - have a new Sachse 5a regulator. Has connections B- earth, Battery B+, gen field coil (DF), gen output (D+) and 61 which wires through the gen light and back to in ignition - so is +12v when ignition is on.

On the generator DF shows 28 ohms to D- (earth), D+ shows 24 ohms to D- (earth). DF to D+ shows 4.5 ohms.

Gen light comes on with ignition but never goes out. DF is only showing 1.5v at idle and 2.5v at (by ear as tacho is not connected) 4000. I would kind of expect this to be higher as the regulator should energise the field coil?

B+ battery output from regulator is only 1.5v rising to 3v.

Generator was working find before the strip down - have recheck all the crimps and all look find. Anyone have suggestions for further troubleshooting - do the resistances for the gen look correct?
 
Hi Chris, try reading back about a month or 2 on Grants thread called Workshop Stories in Some Assembly Required. His personal bike has had M Unit issues. It has some useful info on them. The M Unit stuff starts at thread 1394. No so encouraging.
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Workshop Stories

Sleep is over-rated.
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Thanks VInce - hopefully my m-unit is a much newer model so they should have ironed out the issues.

I think that this is not m-unit related - the only relationship between the M-unit and the reg/gen is supplying 12v via the gen light to connection 61 when the ignition is on - this seems to work fine.
 
These are strange ways to test your charging. Normally voltage rise measured across the battery terminals as you run the engine, what do you measure there? If you have an amp meter, measure amps between the wires and the positive side of the battery. If you want to test the generator itself:
 

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Sorry - probably should have stated first that there is no rise in voltage across the battery when the engine is running - so no charging from gen/regulator - so troubleshooting that.
 
Still does not explain why I am getting nothing (well 3v) out of the B+ on the regulator. If the gen can supply 30v that should be enough for the regulator to supply the battery. Maybe a bad regulator? Not sure what other tests I can do.
 
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You are sure you have a really good earth from the regulator. Take it from the B- terminal to be sure.
It really should have nothing to do with the M unit. All that is doing is giving 12v to the gen light. Disconnect the gen light wire from the regulator 61 just to be sure. If that wire is earthing anywhere you will get your symptom.
 
Wonder how far that instruction sheet can be trusted, if the author cannot distinguish between alternator (AC) and generator (DC) ... :rolleyes:

Just went through a Motogadget m-unit nightmare myself. For some strange reason the battery had run low and the m-unit decided to call it quits and shut down. No amount of coaxing would revive it, only once the owner turned up and performed some magic with his "smart" phone did it resume service.

Not so sure I'd place my trust in one of those, instead of simplifying the loom, it makes matters quite complicated. Sure, wire cross-section can be drastically reduced and all sorts of fancy buttons and switches can be used, tidying the loom a great deal. But I don't see the real world benefit for our analog clunkers.

piet
 
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sfcpiet said:
Wonder how far that instruction sheet can be trusted, if the author cannot distinguish between alternator (AC) and generator (DC) ... :rolleyes:

Just went through a Motogadget m-unit nightmare myself. For some strange reason the battery had run low and the m-unit decided to call it quits and shut down. No amount of coaxing would revive it, only once the owner turned up and performed some magic with his "smart" phone did it resume service.

Not so sure I'd place my trust in one of those, instead of simplifying the loom, it makes matters quite complicated. Sure, wire cross-section can be drastically reduced and all sorts of fancy buttons and switches can be used, tidying the loom a great deal. But I don't see the real world benefit for our analog clunkers.

piet
Click to expand...
Making simple machines complicated with the aim of not riding them is a heavy trend in the "classic motorcycle" world.
Paul
 
hooksey said:
Happy to report…… worked faultlessly whilst in my possession 😉
Click to expand...
"Mine" worked OK too, until the battery mysteriously went flat. New LiFepo, new solid state regulator, charging circuit confirmed OK after running again.

I do appreciate the monitoring features the m-unit offers, I was especially interested in draw from the ignition as an experimental DMC with low-resistance coils is fitted.

Still, I think I'll pass on this...

piet
 
Earth is direct from reg to battery and have double checked it. No dip switches on this reg - just a potentiometer for setting the voltage output - have not fiddle with this yet as they are meant to come set correctly.
Hooksey - thanks for the manual - I had that one downloaded and printed for the initial setup. The 5a is listed as correct for a Laverda 750 (and the reg was supplied by Red so should be the correct one). Just want to check everything before I start thinking the reg is not good.
 
What is it with all these Regulator issues lately, I had overcharging issues a while back and probably did for ages without knowing it, and a few others as well. I had a very unpleasant ride home for 150ks on a dark night with a blown headlight was a symptom of exactly that issue discovered by accident probably a year later. My repeated suggestion about a dash-mounted Volt metre might show up a few more regulator issues still hidden out there.
 
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