Maybe Bad Ignition Switch - Need Opinion

[Groover]

Hope someone can help narrow this one down for me.

Bike started sputtering occasionally yesterday (2-3 sputters at a time, only a few times overall), almost as if all power was lost in those sputters and pretty sure dash lights would flash off matching the sputtering. Parked for a minute to take a break, then I turned and no dash lights and no start. Lifted the seat, checked some various wires visually, didn't really move anything, then I tried the key again, and all was there and the bike started. I don't have the side-stand switch anymore, but even then, if I remember correctly, the dash lights would still come on when the key was turned, but not the starter when the side stand was engaged.

Is this a sign of a failing ignition switch? I have been caught in the rain a few times lately which already caused a dash light to go out, maybe more is failing in the dash due to that?

If the switch were to fail on the road, is there an easy way to jump the switch to get it started in case of emergency/stranded?

This is on a 1981 G5, original I think stock folding key type switch, and new, but stock type wiring.

Thanks for the help

[Kev m]

One quick way to see if a switch might be bad is to turn it on and then place the tip of a tool (like a screwdriver) on the housing, and tap it lightly with a rubber hammer/mallet. If the lights flicker like the switch is being turned on/off with impact you know there are loose contacts to or in the switch. It's how I confirmed the ignition switch was bad on my Jackal all those years ago when the motor cut out once or twice when I hit a pothole/bump on the Blue Ridge Parkway.

[Chuck in Indiana]

It is "probably" the switch. At any rate, it is easy to bend the 3? tabs, take it apart, clean the old hardened grease off, brighten up the contacts with a stainless toothbrush or equivalent..and apply fresh Vaseline. Naturally, pull the negative lead off the battery first.
As a work around on the road, just pull all the wires out of the switch, zip tie them together and wrap the whole mess in electrical tape. (from memory, always suspect any more.) 

[Groover]

Ok, perfect, thanks for the replies and tips. As for the emergency wire wrap... do all the wires at the switch need to make contact for all to operate, or are you pulling my leg?!

[Antietam Classic Cycle]

+1 on what Chuck wrote. No, he wasn't pulling your leg.

[Kev m]

When mine went out on the road I checked a diagram and found there were two pairs of wires that needed to be mated - one was for the ignition/EFI circuit and the other for the lights. I actually cut out the ignition switch and crimped those wires to two toggle switches we got at a local hardware store so I could ride out the week and get the bike home. I would just walk up to it, click the two toggles over and then hit the starter button... I used the steering lock cylinder to keep someone from just doing that and riding off that week.

Anyway if you needed to it should be easy to check a diagram and figure out what connects to what.

[Groover]

Ok, thanks again. Very much appreciated!

[Tobit]

I don't know about the '81 G5, but on my '86 LMIV all of the bike's running current goes through the ignition switch contacts.  I discovered this when I added a 100W/55W halogen headlamp.  I experienced symptoms similar to yours and found that the ignition (and handlebars) switch contacts pitted from the excessive current.  I did what was suggested above, cleaned and dressed all contacts, but also added relays for the headlight, and the problem was solved.  Now my ignition switch only activates the coil in a relay which is rated for the full electrical load, including starter relay, but not the starter solenoid and motor of course.

Good luck,

Tobit

[Old Jock]

Does sound like the ignition switch from your description, it carries quite a load

As far as getting the bike to run, it may be a bit trickier.

Feed to the coils is directly from the ignition switch then through the kill switch to the coils.

If the coils are in one of the side panels and the battery in the centre as most Tontis, then it might be easier to run a jumper wire from the battery pos to the coils then insulated/taped off. In an emergency you could then pull off the loom pos connection and put the jumper wire on. The bike would start but you might not have lights/brake lights indicators etc:

You'd also need to pull it off when you stop the engine for more than a few minutes otherwise you could overheat the coils. Hardly ideal, but when I rewired my LM1000 engined bike using an M-Unit, I put a similar "Get me home" wiring arrangement in case the M-Unit failed (so far it hasn't)

That's just from checking Carl Allison's diagram for a G5, as I'm not familiar with that model.

[Groover]

Thanks again for the additional replies. I'd like to the the relay conversion some day. Attached is the wiring diagram for a '78 G5, which has a slightly different dash wiring than the '81, but I think the ignition switch part is the same.

[centauro]

Ok, perfect, thanks for the replies and tips. As for the emergency wire wrap... do all the wires at the switch need to make contact for all to operate, or are you pulling my leg?!

The 4 wires at the ignition switch are brown, red, white, and green. In an emergency, to hotwire the switch and make the engine run, you join the red one (from battery/rectifier terminal) with the brown (to fuse box) and to white wire, which feeds the coils (via the kill switch by the throttle). No need to do anything with the green wire; that one is to power the rear parking light when switch is in Park position, but if you do this at night, it needs to be connected as well, otherwise you have no working tail light.

Of course, once you reach your destination, you would disconnect the battery ground to turn everything off until you fix /replace the switch.

[Furbo]

You can likely go to any local autoparts store and get a keyed switch for less pain than it takes to repair the original.

[Tom]

+1 on cleaning out the switch.  If you pull it apart, chances are that you have corrosion on the contacts similar to the green/blue crud that you get on a battery.  Clean and reconnect. 

+1 on replacing the switch with a universal one.  That works too.  Just check the connectors.

BTDT on my '80 Convert.  Before the internet.  I still have it too.

[Groover]

It was the switch. Confirmed last night, got stranded but putting pressure on the key pushing forward got me home. Cleaned the internals, could use a replacement "backplate" but I flipped the contact pieces and I think it will do for now. Might get a replacement, but wanted to keep the original for now. At least I know for sure where the issue is now. Thanks again for the tips.

[Kiwi_Roy]

https://www.thisoldtractor.com/guzzi007/schematics/1978_G5.gif
A jumper from the battery to the switched fuses will keep it running
the switched fuses are the ones on the brown feed from the ignition switch.

[Groover]

Some pics, looks like the red was the one with loose contact and also overheated. The gunk also prevented the spring action for the contact plates inside, which may have been the issue. All is nice and springy now, bike runs but replacement or backplate replacement is on the list.

[Chuck in Indiana]

Many don't do this simple tear down/clean/lube of the switch.. they'll buy a new one then need a key for the ignition and a key for the gas tank.
Most old Guzzi problems are just from lack of maintenance of the electrical system. It takes maybe a Saturday to completely go through the ignition and electrical system, cleaning, replacing brittle connections, etc.
This stuff is getting old. Some PM will make them "run good, last long time." 

[Groover]

It been happening again. Gave in a bought a new switch on eBay, then contacted Greg Bender for a harness that that goes  from bullet to spade for the new switch. He does great work as usual and nice guy overall. I could've cut some wires and put spades in, but wanted to do it right and clean [size=78%]and he's the go-to guy for that[/size]