Won't start. Again.

[Bixxer Bob]

I finally got round to washing the Girly after France then was going to ride it back to the garage and.....  no go.  Same as last time, churns over but no firing.

I had a think and initially convinced myself that it could be sidestand switch because clutch switch stops it turning over, side stand switch stops it running.  I wanted to do a quick check on the switch, but found the plug is under the airbox and the cable is routed behind the waterpump    FFS Mr Triumph why would you do that????  SO, after removing the indicators, Bagster cover, battery etc etc I finally had access to the plug.  I disconnected it and checked the switch; all fine.  Then I remembered that you have to engage  a gear before the switch acts as a cutout, so the last half hour hadn't helped. 

Next I did a quick check of the injectors and they weren't firing.  Last time this happened remapping sorted it so I got the laptop and blew in a new map.  Zilch. Nothing.  Changed the ECU.  Still the same.  But at least that proved it's on the bike somewhere.... 

While hooked up I decided to check the codes and found number two coil open circuit or short circuit.  I gave everything a wiggle and voila, she fired up. 

So here's today's so far unproven theory.   The injectors and the coils share a common 12v feed; they are controlled by the ECU which grounds each coil or injector when it wants it to fire.  In order to take down all the injectors (and probably the coils as well) there has to be either a short to ground on the 12v feed - which would almost certainly result in either a blown fuse, burnt insulation or both - or a leak to earth via insulation breaking down in a coil, which may not be enough to blow the fuse, but could drop the volts enough to stop the coils and injectors working.  This is supported to some extent by the fault code in the ECUso tomorrow's job is to change the coil.  As it happens I have a spare....

I am beginning to tire of this 

Oh, and having taken the Bagster cover off after all those hot miles in France, I find suddenly I now have decal blisters 

[nickjtc]

We feel your frustration, too. But we put up with all this bs because we love the bikes......... don't we?

And as to why does Mr. Triumph make it a veritable jigsaw puzzle to get to anything on the bike? Maybe there is just no better way. For example on the Steamer we have to remove two front side panels and the screen to get at anything at the front. On the Roadie there are side panels, infill panels, fascia panels  ...

[metalguru]

The Brown/Pink cable supplies both the injectors and coils as you quite rightly say.
The supply for these comes through fuses 6 & 7.
The source of supply to the fuses comes from the main power relay pin 8.
It may be a good idea to have a look at the terminal block from engine loom to frame loom?
Sounds like an oxidised connection somewhere.

[Bixxer Bob]

Already checked Nige, everything's clean.  It was a bit disconcerting that it suddenly decided to start after I was playing with the loom (coil connectors, sidestand switch plug etc). If fact at first I thought that disconnecting the sidestand switch had done the trick but subsequently reconnecting it didn't stop it again so it's not that.  What I can't be sure of of course is that there isn't a broken wire inside the insulation somewhere.  Time will tell.

Anyway, I took off the damaged Blueflame this morning, fitted the old standard exhaust, changed #2 coil, fired her up and she's purring like a kitten; can't remember the last time she ran that well.  Throttle bodies were spot on too which was a surprise as they don't usually stay set for long let alone after 2500 miles.  For now I'm just going to finish the service and fit the new tyres and ride her for a bit; see what happens.  I guess she'll be down a couple of horses with the old exhaust but I can live with that.