Help Please -- Charging (NOT)

  • Thread starter Thread starter jotajohndude
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J

jotajohndude

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Hi Everyone,

I hope someone out there can help. My 1972 SF750 is apparently not charging. Th generator light is showing and the battery is not charging.

Please bear in mind I am really as thick as two short planks with anything electric so please can any help / guidance or explanation be given in the most simple of terms.

john
 
Hi John
Basics first, is your v belt still intact and is it correctly adjusted?
Cheers
Andy
 
AndyB said:
Hi John
Basics first, is your v belt still intact and is it correctly adjusted?
Cheers
Andy
Click to expand...

Andy
We clearly have different levels of "basics" can you explain "V belt" I know I am a complete pillock but i have a blank when it comes to Elektrickery 
 
jotajohndude said:
<snip> .. can you explain "V belt" 
Click to expand...

Here John

750.jpg


It's the belt that runs off the crankshaft to turn the generator.

Ciao

Craig
 
Adjustment?
there is none, its either there and driveing the dynamo, or its not.The replacement belt can be bought at any belt/transmission/chain supplier it is called a "Z495"  the "Z" being the cross sectional shape of the belt and "495" being the length as measured around the top part of the vee.Or of course from a laverda dealer at a premium price.

I would say its far more likely to be a visible fault at the regulator box.Remove the fuel tank, and right in front of you between the frame rails is a silver box about three inches square and about as fat, it has "BOSCH" embossed into it.useing your fingers, check that all the wires comeing to it are still atatched, the brass terminal ends on those wires very often break, due to vibration, and age hardening of the rubber mounting system for the box.

Has the bike been OK lately? is this a new problem? has any body being doing "repairs" recently?
with the engine running and the headlight on, can you detect a very slight "brightening" of the headlamp, when you increase revs to about 3000 or so? is the battery actually getting flat,? can you start the bike useing the starter motor?

The more you tell, the more we can help.

CLEM
 
I second to check the wiring of the regulator first. Very often, the cable looks to be still attached to the box but is actually broken. Had a funny fault here, too: the ground cable was attached to the frame as should be. However, the frame had been re-painted and not enough current went through the screw...  :o

attached it to the battery directly and yeepy - it was charging again!

some months later, same issue appeared again, this time caused by the earth/ground cable having a broken connection to the O-connector that it is mounted to the regulator to....
 
CLEMTOG said:
Adjustment?
there is none, its either there and driveing the dynamo, or its not.
Click to expand...

Ah sorry, forgot that only the alternator equipped bikes like mine have an adjustable belt.... :-[
 
Clemotg and all thanks for the advice.

I will crack on and check the regulator.

I have not had the bike long and have not used / run it before this weekend. It was ridden to me when i bought it a distance of appx 250miles and it made it quite ok though i noticed upon its arrival the charging light was on.

I've done nothing with the wiring loom / electrics. Though like lots of old bikes the wiring is a bloody mess and needs to be tackled soon.
The gen / charging light is showing
the battery is only showing 11 volts when the engine is on fast tickover (2000rpm)

I will check the regulator and report back

ta :D 
 
Wow,

I am seriously impressed, Clemtog and others.

Fault sorted thank you!!!!!

Tank off and there was the Bosch regulator as described and even a complete arse like me can spot a broken connection (as suggested) so I cut off the end of the broken connector crimped on a new one connected it back to the regulator and hey presto that bloody annoying red light now goes away over about 1500 rpm.

Job well done and a huge thank you

:D :D :D 
 
John - excellent news...and there's nothing more satisfying than spotting & fixing a fault like this  :)  Well, apart from getting on the thing and riding it of course!  ;)
 
Very glad you are sorted,and that my dignosis was usefull, I have been 0wning/rideing/running/restoring/racing/abuseing and even occasionally polishing Laverda motorcyles for 38 years now, very nearly exclusively, so I must have remembered a few things on the way.
CLEM
 
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