After a week of blow torching and hammering I've decided to take the frame into Carrick Engineering in Prestwick, for a modest amount they'll remove the broken bolt and sleeve using acetylene torches and brute force meaning I can then strip the frame and feel like I'm starting to something constructive rather than destructive.

Recognising I don't have the appropriate tools to do these jobs is something that I'll realise quicker in the future though half the fun is in trying yourself.
At least its not occupying all of my time now and I'll start with stripping the powdercoat first.
I'll fire up the blowtorch and hope it doesn't rain all weekend.The other alternative is traditional paint stripper which is fairly ineffective against powdercoat so I'm told or gasket stripper which is fierce but quite nasty stuff to work with.

The bearing cups are off and I removed the steering lock, annoyingly the little lock cover you can see in the previous pictures went flying into space when I hammered it off, I then wasted the best part of an hour looking for it before resigning myself to making another one from brass sheet.
I was all ready to drill out the lock and just quickly checked a website for info on the exact drilling point to avoid the hardened tumblers inside when I noticed 'the quick way'- number 3 on here-
http://w6rec.com/duane/bmw/lock/index.htm
14 seconds later the lock was out.

Just as one sheared bolt is fixed another two come along to try my patience, I think I'll grind off the captive nuts on this though and get new ones tacked on in the same position.

I have found that you can get clamp that encircles the pipe with a captive bolt attached and that may be an easier option meaning I just need to grind of the broken bolts and clean up any remaining weld.

The first shiny thing arrives

A new set of exhaust nuts came through the post surprisingly quickly from Italy.
It's the first thing I've 'fixed', only the rest of the bike to go now.

I've also decided to attempt a repair on the tank badges and side panel logos, these were very tatty and I would normally just replace them, however, they are an eye watering £58 per pair for each badge, that's £116 for four bits of plastic.

I have cleaned them and rebuilt the broken piece using parts of a sprue holding a model kit.
This may not work or look convincing when finished as I haven't yet found a decent coating to replicate the chrome but it's worth a try just due to the costs of the replacement parts.

Frame is nearly apart, only a couple of bearing holders and the centrestand to come off, the pivot nut on the stand sheared so I'm not sure how to tackle that yet.

I'm sure the bearing cups just push out but I'll check that before bashing away with a mallet first.

The engine is now out and on a bench, a juggling act involving a car jack and short length of wood to manoeuvre the engine out through the right side of the frame, once it had released itself from the rear mounts it was a relatively straightforward task, it's not heavy just awkward.

Surprisingly light though it will need a clean, the flywheel nut has been cracked, I'll do the belt change and that side of things later, I'll also need to sort the clutch side where a little oil leak had started to show, that'll need the clutch out first, all in due course though.

The rolling frame was then rolled out.

I then power washed the frame to get the worst of the greasy grime from it and will tackle the swing arm and forks next. It'll all get recoated in time but cleaning it now makes handling it a lot easier in the meantime.

Wheels are now at the side awaiting further attention.

The flywheel nut is undone.

Not an easy one man job I have to admit, thats why I asked for help holding the flywheel while the nut was
undone with a breaker bar!
A simple yet irritating job thats awkward if your on your own.

That gunky covered thing in the sprocket well appears to be fibreglass, probably put there as a bodge it fix when the chain snapped, quite what it was meant to achieve there I'm not sure, the only benefit would appear to be muck proofing the cam belt and generator..
I can either extend the metal separator on the crankcase to cover the gap or I can rebuild it with a chemical metal compound, neither will prevent damage if the chain were to break again but it may keep the grime out of the generator area a bit more effectively than loosely packed fibreglass matt held in with congealed chain lube.

Mundane tasks chip away at the whole thing in small chunks, the right crankcase cover was unbolted and the chain was split and removed. My first half hearted attempt to get the flywheel off didn't work, I'll need to wait until I have more time and room to move as the working area is quite cramped and awkward when the bike is fully back in the garage. This weekend I'll be able to get it out a few feet meaning I can get a decent purchase on the flywheel holder while undoing the central nut without trying to balance over a couple of kids bikes.

There was an odd piece of debris(or so I thought around the front sprocket, I pulled it out with pliers, it may be plastic or light alloy I haven't bothered to clean it to find out. but looking at where it came from around the sprocket Looked a bit odd to me, so after a cursory wipe with a paraffin coated rag I notice the castings were rough in a couple of places.

Definitely broken, I've seen this on Ducatis before and its a sure sign to me that the chain has snapped on this bike at some stage in the past, it will have bunched around the sprocket breaking the metal at the front and will have whipped up breaking it directly above the sprocket. On an air cooled Ducati like mine that would have burst the crankcase but fortunately it seems less terminal here. You can get strips of steel that bolt on as protection on the Ducatis but they have convenient bolt holes in that location to attach it to, I think I'll just have to live with this.
Interesting evidence of the bikes history.

The stubborn exhaust nut is finally off.
I tried, releasing fluid, a special spanner, a blowtorch, but finally it got down to brute force and ignorance.
A rummage in dad's old toolchest revealed a couple of old heavy caulking tools,similar to heavy blunt chisels and with a glove under it to protect the alloy in case I slipped I then battered the nut with the hammer and chisel combo until it was off.
The nut is now junk, I did try the other nut in the port working it back and forwards to try and clean up the threads in the alloy cylinder head and it has made a visible difference in the definition of the threads in the port, I revisit this sometime later when its all going back together .

Here are the old nuts the stiff one is the one on the right.

New castle nuts are now on the shopping list.
From here:-
http://www.morinispecial.it/joomla/index.php?option=com_wrapper&view=wrapper&Itemid=168

I also tried a quick wipe over of the wiring with a paraffin soaked rag and it was like moving from B&W movies to technicolour is one wipe, gone is years of sticky grime. I'll do it more thoroughly in the next few days.

A week or so spent pulling bits off the bike has resulted in this.

The next stage would be to remove the engine from the frame but until I can remove that header pipe that'll have to wait.
There's a castellated nut made from relatively soft bronze holding the header pipe to the cylinder head and it wont move, even with a specialist spanner bought specifically for this job. I've just tried Plusgas penetrating fluid on it and will persevere for a bit but if it doesn't look like there's any progress there then it may have to be partly destroyed to get it off.
I've found a firm in Italy that sells new ones at about £40 for a pair.

I'm still trying to work out which version of the wiring I have, not helped by it all being so coated in grime that most of the wires are just shades of black. A bit of cleaning there may make it clearer.
At least some of the components like the coils and reg/rec box look new, so someone has rewired part of it in the near past.

I've decided that after I get the existing powdercoat removed from the frame I wont be redoing it, I think paint will give me a nicer finish,if not as durable. I may or may not do this myself. I think it ought to be black too.
The wheels will definitely need repainted, I'll probably get them done in a paint shop. 'Skoda Donington grey' is the paint colour that matches the original colour so I'm told.

The engine number appeared out of the muck on the back of the crankcase, apparently put there by the importer as the factory didn't bother to stamp them and it's a legal requirement in the UK.

The tape around the headlight was holding it together as I suspected, however it wasn't as bad as it could have been, the only things missing were two small nuts and bolts. I cobbled some together for the moment and will fix it properly in due course.