Now it's the electrics...

[ferguzzi]

So these issues are still on going. I thought it was sorted, but it seems not.

I left the bike at a good dealer, and basically gave them permission to do whatever.

So wires were replaced, as was the charger/rectifier. I rode it once, no problem, left it a week, and tried to start it up, and no tacho or battery light. It started ok, but it wasn't charging obviously.

So I replaced one relay(the second one), and everything works fine.

That was 3 weeks ago, I've since ordered the recommended ombon(?) relays, and just fitted the them.

I presume I can replace all 5 relays with the same model of relay?

2 things happened. The 15 amp fuse blew( the starter fuse), and I then noticed the (2 year old)battery was flat as a pancake.

Any thoughts?

[Scud]

I've been having some warning signs regarding electrical issues at startup on my LeMans, so I'm keenly interested. Here are some thoughts:

 

How about putting in one of those 15 amp MAXI fuses that Docc recommends frequently? I did it on my LeMans as a preventative measure. It's a somewhat involved wiring job - the MAXI fuse does not fit in the standard fuse block.

 

A previous post mentioned cleaning the relay contacts - so that's inside the relay blocks. I think the way to do that is to fold up some fine sandpaper and slide it in and out a bit - or maybe you can use a tiny file.

 

You can use the same 5-pin OMRON relays to replace all the relays (as you've done). Maybe put a little vaseline on the pins to keep the corrosion down.

 

If the bike's been sitting a bit, you might need to condition (or replace) the battery.

[ferguzzi]

Well, it's not that I used the wrong relays, then.

Weird that the fuse would blow only when I replaced them all though.

Weird too that the battery is suddenly flat. It's been flat twice in 2 years with all the charging issues, so it's not inconceivable that it would die now.

It just seems a bit of a coincidence!

[docc]

I recently replaced some relays in a friend's Rosso Corsa and squeezed the outgoing relay enough upon removal to blow the fuse in that circuit.  New fuse (new relay): no problem.

 

The MAXI fuse is a solution for the 30 amp "regulator" fuse. A blown starter fuse could suggest bad connections at the starter (or starter solenoid), or even the loose starter motor magnets known to afflict the Valeo starter.

 

Simpler yet: cleaning and inspecting the ignition switch if you have not done so already . . .

[Kiwi_Roy]

The fuse in the start circuit is really too small Luigi forgot how much current the start solenoid pulls at inrush, about 50 Amps.

Normally the inrush current only lasts about 1/10th of a second while the solenoid pulls in then drops to about 10 Amps, the fuse can handle that.

If the starter doesn't pull in cleanly due to a flat battery or perhaps a tiny resistance the solenoid may sit there pulling a heavy current (for example 30 Amps) enough to blow the fuse but not have enough to engage the starter.

 

This is a problem with some of the other Guzzi models where the solenoid is wired through the ignition switch the usual fix is to change the 15 Amp fuse for a 20, the other fix is to provide a direct feed to the relay bypassing the switch, not always simple.

 

The start relay should not be powered through the ignition switch it cannot supply the heavy inrush current  reliably, check by pulling the relay and see if there is Voltage on the 30 terminal. Thats the pin furtherest from the 3 small ones with the key Off 

I posted a sketch explaining the starter circuit a while back, I can't post it from here.