www.boxertrix.com

Thought I would show what I discovered whilst hunting for the gremlin causing my surging at around 3-4000 revs.

https://www.dropbox.com/s/m6nohixw227m1ez/coil3.jpg
https://www.dropbox.com/s/36jz4yyxfsj72x7/coil3a.jpg
https://www.dropbox.com/s/jnrv0zmnqkr0266/coil3b.jpg
https://www.dropbox.com/s/58po03w2x1mzchd/spark1.jpg
https://www.dropbox.com/s/s1c0dec5ooh4ymo/spark2.jpg
https://www.dropbox.com/s/vxirfcguz6ahys9/spark3.jpg
https://www.dropbox.com/s/y69fz6x8ufk4dyy/spark%204.jpg

I have also uploaded a photo of each spark plug. The 2 lean plugs were the top plugs and the two blacken plugs were the bottom plugs. Presume, they still look ok and wont have been destroyed by my faulty coil pack?

Blackened lower plugs is normal on a twin spark engine.

And coil caps melting happens when they've been failed for a long period of time, i've even seen them catch fire and burn the cap wiring, that's why there's a purpose section of wiring available from bmw to repair those that do get burnt.

Thanks steptoe. Seems like I discovered mine on the knick off time!

What's the easiest way to test them? Presume using a spare spark plug and starting the bike would do it as I could then look for a spark?

I'd suggest that when you get the new ones, you coat them in high-temp resistant grease (silicon grease) before you re-install them.

My theory is that the plug caps aren't really designed or optimised for being 'outside' (as opposed to under the bonnet of a car) and their waterproofing can be easily compromised. Every plug coil I've seen fail has had evidence of internal corrosion.

Anyway - since I started coating the coil caps I've had no troubles with them whatsover.

It might also help that the newer coil caps are possibly better made (the grey ones).