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Old 12-05-2012, 12:46 PM   #1
MikeO OP
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Joined: Jul 2002
Location: Scarning, Norfolk, today...
Oddometer: 7,089
Unexplained fuel fire on 2002 1150GS Adventure - clipped from MikeO's ride report

So –what happened?

The short answer is – I don’t know.

First – a recap…

Originally Posted by Mike O View Post

The lovely Claire and Letty wave me goodbye and I set off.

In order to get onto the motorway I have to double back through an industrial estate. Without warning the bike slows – it has started firing on only one cylinder. I keep the engine running and turn into a roadway in the industrial area. I find I can keep the engine running on one cylinder, so long as I keep the revs above 2500. I set the throttle lock to this setting and put the bike on its side stand...

I feel each of the headers in turn with my (gloved) hands and the right header is considerably cooler – indicating that this is where the trouble is. I take off my gloves, pull my tool kit out and undo the two bolts holding on the right hand side-panel. I turn away to pick up my camera, turn back, noticing a sudden smell of petrol and, with a dull whoosh, a large fire develops in front of me. I later found that I took a picture – probably a reflex action.

I quickly turn off the kill switch to stop fuel supply, but it’s obvious this fire is going to be catastrophic.
So, the bike started firing on one cylinder (the left). I stopped, keeping the engine running at about 2500 rpm (from memory) using the throttle lock at nearly full throttle to do this.

Being a geek – I just took this as another part of the ride, so took time to take two pictures of the bike (the first one is above – here’s the other)…

With the engine still running, I took my toolkit out and removed the two bolts holding the right hand side-panel on. I turned to put the panel on the pavement, picked up my camera and was just turning back to face the bike when I noticed a very strong smell of petrol. Almost at the same time a significant fire developed with a ‘whoosh’ clearly audible above the engine. As I mentioned at the time, I must have taken the picture by reflex, because I got busy rescuing kit etc straight away and only saw the pic later.

Now it’s very tempting to tie the fire and the misfire together, as one happened so soon after the other. One thing’s for sure – we’re never going to know for certain what happened, because the components involved are plastic, rubber and alloy, so any evidence is long gone.

From a maintenance point of view, all the fuel pipes had been replaced during the winter refit (2011/12) and chromed brass QD connectors fitted with BMW crimped hose clamps. These had performed perfectly all the year. The last time the QDs were apart was in October to chase down an electrical fault (nowhere near the fire and not related), and the bike had run several thousand miles without a snag since then.

The fuel injectors had been serviced in the Spring of this year – and had performed faultlessly throughout the Dolomites trip in July and this trip.

But let’s have a closer look at the fire picture…

I can clearly see the red fuel line disconnected and the electrical connection for the injector seems to have come off.

It certainly looks like something fairly dramatic happened when my back was turned. I know for sure that the QDs were correctly joined when I took the side panel off – because I was looking for a fault in that area. I am familiar with what this part of the bike is meant to look like and am convinced I would have seen the injector connector disconnected…

To produce a fire you need fuel and a source of ignition.

Could my injector have come apart somehow (fatigue crack – whatever)? There would certainly be a source of ignition (ie the spark plug and any unburned fuel) in the cylinder and throttle body, if it were all suddenly exposed to air.

I can’t discount somebody tampering with the bike – it was under a carport in front of the hotel and there were a load of drunken footballers (youngsters) staying the night before. But it started and ran fine for half a klick or so, before the misfire started.

All speculation - we’ll never find out. But something fairly dramatic happened to the right side of my bike in a very shot space of time…
All text & original photos © Mike Oughton 2004 - 2015
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