I would normally agree with your "if it aint broke" sentiment - it is one I normally follow, but in this case it is a miracle it runs at all given the corrosion around the earth points, and the general state of everything. I think it would just be a matter of time before it stopped working.

Yes, they are JIS and I have a set of screwdrivers - I have learnt the hard way in the past.

Anyway, managed to get the 3 screws out that hold the "backplate" with no real dramas - just had to be very inventive with some small mole grips as the screwdriver which was JIS very quickly lost any traction in the screw heads due to the rust. The actual threads in the casting were surprisingly clean.

With the exception of the pulsar screws which eventually came undone, all of the others sheared off, luckilly leaving enough to be able to grip - more of that later.

The lighting coil and source coils eventually came off over the broken screws.

I now have a backplate with one of the cable loom retaining screws sheared off flush - not big deal to drill out and re tap, or re locate.

There are also the 4 coil mounting studs that I have still to remove, earlier I heated the studs to cherry red and squirted WD40 and penetrating oil around them while still hot - very impressive clouds of white smoke. I am going to leave it overnight and repeat in the morning then see if the studs will come out.

I had to cut the pulsar wires to free it from the backplate as it will not pass through the slots in the backplate - simply re solder & sleeve to re assemble.

So over the next few days it will be a cleaning job / stud removal and re build with new screws.

I'll see how it runs when everything is re assembled, if it is OK then I will leave as is, if not then Rex's conversion is the way to go I guess - what are others saying, good / bad?
 

This was the mess I was greeted with when I pulled the flywheel off - inside of the case was the same.I blew most of it off using an airline, it was then a case of using various tools including a dremmel to clean the rest off - to think that the bike was starting and running OK in this state is hard to believe, but it was.Once cleaning and refurbishing is complete I'll post up a pic or two.