Sf2 Lights playing up

Lyndoneil

Lyndoneil

Full member
Location
Towcester uk
I know there is a countless causes of electrical problems, but I was hoping that one of the geniuses here could at least point me in the right direction, as at the moment I am totally stumped.
The symptoms are, the bike runs fine, horn works, indicators  and brake lights are ok but the head lamp,  rear lamp and instrument lights only work when the ignition switch is in the parking light position, in that position the flasher, dipped and main beam work fine, the parking light is also on. But when in that position the ignition is off.
The lights were ok for a while, but I don't know if I should be investigating  the ignition circuit or the lighting circuit, the lack of a really good circuit diagram doesn't  help.
 
I recommend you replace the Bosch Prince of Darkness Key Ignition Switch with a Heavy duty Toggle Switch and see what Happens.

SF's were plagued with Electrical problems over that God Dam Bosch Key Sx.

Granted dissembling that Bosch Key Sx and cleaning it should solve the problem - But it doesn't.

Your ride can shut down in front of an 18 wheeler on your Ass ;o(
 
Laverda SF said:
I recommend you replace the Bosch Prince of Darkness Key Ignition Switch with a Heavy duty Toggle Switch and see what Happens.

SF's were plagued with Electrical problems over that God Dam Bosch Key Sx.

Granted dissembling that Bosch Key Sx and cleaning it should solve the problem - But it doesn't.

Your ride can shut down in front of an 18 wheeler on your Ass ;o(
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No common ground whatsoever with what the post is about, Ron. SF2 had a ND ignition switch.
 
Some odd things going on there. I wouldn't have thought anything other than park and tail light should work when in the park pos. So I'd agree that the ignition switch is the prob, wired incorrectly or internal contacts awry.

One of the problems with a std ign switch is that too much power goes through it. Fitting a relay can bypass it, so all it's doing is sending a signal to the relay. Another no-brainer is removing the ceramic fuses from the fuse holder, cleaning the tangs in the holder and the contact patch on the fuses and making sure there is good contact there. They can be problematic, but with a little maintenance, don't cause much bother.

I'd start with those two things - remove the ign switch and dismantle, clean, repair as nec.
 
My Pantah was having issues a while back, wiggle the key would kill the bike so I bought a replacement from a reliable shop. This keyed switch connected as the original one was wired internally wrong. When switched to the run position it also connected the park system as well. The story I got was Ian Gowanloch had a large bunch of switches made and they arrived wired internally wrong. So I needed to alter the way it connected to the bike, complicated, or fix the original switch.
 
The ignition switch is still available new (or at least a very close copy of it). It was the same as on old Suzuki's (just like the ND instruments or the handlebar switches...). In Germany, Polo Motorrad does have them:

https://www.polo-motorrad.com/de-de/paaschburg-und-wunderlich-zuendschloss-60030000020.html

but you'll get them on ebay, too:

https://www.ebay.com/sch/i.html?_from=R40&_nkw=ignition+switch+suzuki+GT&_sacat=0&LH_TitleDesc=0&_sop=15

check the connectors are the same as on yours, then it should be a direct swap.
 
Some, earlier, Laverdas used a Suzuki type ignition switch that had only 3 wires.
 
Thanks guys, will investigate the ignition switch and circuit,
Wish it was as easy as just replacing parts, as you know it's 46-47 years old, which has given former owners ample time to replace connectors with particularly crap ones, wires with with ones of every colour imaginable, just so long as it is different  from what it should be, make additional connections which seemingly have absolutely no function.
The ignition switch fitted appears to have 4 wires, brown, orange, red and grey (not used) going to Blue, brown and black, but the circuit diagram shows 3 wires, 2 red and 1 brown.god alone knows which should be which, the loom looks like a plate of spaghetti.
Didn't want to describe the  horror initially as I was trying to avoid  giving you the  pleasure of imitating Private Fraser from 'Dads Army '. 'We're doomed, we're all doomed.
 
Lyndoneil said:
Wish it was as easy as just replacing parts, as you now it's 46-47 years old, which has given former owners ample time to replace connectors with particularly crap ones, wires with with ones of every colour imaginable, just so long as it is different  from what it should be, make additional connections which seemingly have absolutely no function.

Didn't want to describe the  horror initially as I was trying to avoid  giving you the  pleasure of imitating Private Fraser from 'Dads Army '. 'We're doomed, we're all doomed.
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I hear your pain - I've seen some absolutely indescribably bad attempts at wiring on Laverdas. Why people bother when that's the best they can do is utterly beyond me. Good luck - consider paying a good auto elec to sort the whole mess some time soon - or buy a new loom from Wolfgang.

I've found the use of shite connectors to be the worst offence. They just invite trouble, and trouble nearly always obliges.
 
The lighting and ignition circuits are separated by a diode, so that when the switch is in the park position, the lights should work, but not the ignition. Sounds like someone has connected the diode around the wrong way. The diode is identified as item # 61 in the wiring diagram, which you can find in the Green Book.
 
I find it interesting as to what defines a body electrical connector to some people. One mechanic I dealt with years ago went into a tirade because I had used spade connectors. Good quality bought from the local auto sparky who was in business there since the 1930s. This mechanic hatted spade connectors and insisted on changing them to bullet connectors. Didnt make any sense to me, as long as the crimp was done right. These days I like those sleaved premade soldered and shrinkwrapped connectors. Strip the wires poke them in each end and heat, they solder and shrink in one go.
 
Vince said:
One mechanic I dealt with years ago went into a tirade because I had used spade connectors.  This mechanic hated spade connectors and insisted on changing them to bullet connectors. <snip>. These days I like those sleaved premade soldered and shrinkwrapped connectors.
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Back in the day, I would have confessed to a sneaking sympathy with yer man there, Vince.  A well done bullet connection, pushed together using the proper tool - small, discrete and will never come apart (sometimes even when you want it to ...  :-*).  Those new-fangled spade connector thingies?  Ugly, intrusive, take up far too much room and will come apart as soon as look at them ...  >:D

These days, tho', I'll follow suit and allow a small concession to modernity.  Heat shrink and solder ...  :D
 
It's not necessarily the connectors that are either good or bad,  bullet,  spade or whatever, it's more the method of how the connector is attached to the wires,
I'm not a big fan of the ones that come in with the red, blue or yellow plastic sleeves depending on the diameter that are designed to just be crimped plastic and all onto the wire, might be a good connection, might not, might well pull straight out with the slightest of pressure.
I much prefer to buy all the bits individually, crimp, solder and heat shrink with rubber boots over the connections, Then I know the connection is good, as I dont particularly enjoy having to partially strip a bike down 2 days or 2 years later to trace what is causing a problem, spend hours scrutinising a circuit diagram, and becoming a 24 hour auto electric expert of any particular bike just because it was slightly quicker to use that rubbish in the first place. :D
 
If there is a problem with the ignition switch, these guys may be able to help. They can rebuild switches.
I haven't needed them myself. but they were recommended by a friend.
Motorcycle Lock Repairs UK http://www.motorcyclelockrepairs.co.uk/
 
I've checked the ignition switch, cant really find a problem, but not totally sure what I am expecting to find, seems wired correctly and swopping the current from ignition to parking light, but the headlamp etc still only work in the park position on the switch, but I can not find a diode on the light circuit, would this cause the light problem symptoms?
 
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