Misfire!

[John]

The misfire is likely to become more frequent over time. A bad coil is not likely to leave you stranded.
I previously experienced the same symptoms on my K1300, I replaced all 4 coils, spark plugs and fresh coolant. (the radiator needs to be removed for access to the coils so it's worth replacing the plugs if they're nearing their the of life)

[Matt]

I'd just like to get in early with:
Bagsy I'm not carrying Richard as pillion if it does conk out half way through the trip this year .

I say that knowing it'll be fine of course!

[Grumpy jase]

You may well be correct, John. I'm going to have to go out a few more times, I guess.

What can I expect - for it to slowly degrade, or die a sudden death?
And does anything else affect coils - air moisture, cold, etc?

If it is a coil then it is likely to degrade relatively quickly, and the misfire will become more common.  The coils can break down internally, or have a current leak to earth through the casing.  If it is this then it will be affected by dampness, which can make the short easier to initiate, but also how you are riding, as light throttle often means there is more current in the coil to initiate the spark. 

It could also be down to the feed wires to the coil.  I had this on my VFR, where the wires had aged sufficiently that one was broken.  It was generally in contact and hence worked, but every now any again, it would be vibrated free and misfire.  That was a real pain to diagnose, as there didn't seem to be any pattern.

[richtea]

Thanks all. I have several rides I need to make in the next week, so I'll let you know how it develops.

[farmer]

just having a nosey through this, i certainly wouldn't argue with some of the gurus on here... well some i would but generally no, have you ruled out debris in your fuel system or a failing fuel pump as i believe they would produce the same symptoms, when it's intermittent it makes it a right bugger to find, and if working fine at the time of testing i don't think a computer would pick it up.
also as a previous poster said a broken plug lead lead me a merry dance in a souped up escort years ago, went great most of the time but for no reason started missing as it saw fit, usually in an embarrassing situation.
hopefully as the song goes it's lost and gone forever...

[TomL]

A coil which missfires will put unburnt fuel into the catalytic convertor. This can cause the covertor to melt down and self destruct.

[farmer]

would this give a strong smell of petrol?

[TomL]

If I remember it usually gives off a rotten egg smell.

[farmer]

ah yes , i think i heard of that before.
isn't technology great ....sometimes

[richtea]

If I remember it usually gives off a rotten egg smell.

Hmm, with me in the vicinity it's going to be tricky to pin down the true source.

[Costas]

Go and change the coils. 

[Matt]

Go and change the coils.

Philip may have the old perfectly good coils from when he tried replacing on my old bike... if he's still about ask to borrow them!

[richtea]

Hmm, good idea! However, right now, it's no longer an issue.
Been out 4 times - all more than a hour, no problems. On a group ride the bloke behind said he heard a misfire, but I didn't feel anything. I suspect it was just the Akro spitting on deceleration.

The only thing that's changed since the initial problem is the weather - it's warmer and dryer now - but not by much, a couple of degrees at most.

I'm tempted to mount a small lump of wood to the bars, as a touch piece to be used at the start of every ride. The bloke I rode out with on Sunday had a tiny bell, given to him by his wife, on his pannier rack to ward off evil. Quite sweet. The only offers I get from Ms Cashmere are sugar in the tank and part-sawn brake lines. Must be love. 

In the meantime, I'll ride until it returns.

[raesewell]

These thing normally return at the most inopportune moment 

[richtea]

These thing normally return at the most inopportune moment 

Mid-Wales in the rain. With no mobile signal.

However if it doesn't go wrong, there's not a lot to do. Just cross my fingers and get some riding in.
The more I ride the more likely I am to flush it out.

[Edit: 'flush' as in flush whatever petrol problem there is away - OR - flush the problem out of hiding by riding it until properly busts]