To accommodate a longer throw crank, does the K1200 engine have different pistons, or different con-rods, from the K1100 ?

The 1200 has longer stroke and shorter rods. The K1100 engine will have black engine covers and the 1200 silver.

RicK G wrote:The 1200 has longer stroke and shorter rods. The K1100 engine will have black engine covers and the 1200 silver.

Thank you for a very swift reply which answers a major question.
My cover is black, so when I come to rebuilding that one, it looks as though I'll need an 1100 crank and bearings.
I see that somebody does oversize pistons for the Boxer, are they available for the K series ?

To my knowledge the Ks blocks have a special coating that lasts a lifetime, making Reboreing  not possible, the piston rings are made to were out rather than the bore. Some pistons have ring pins some dont. 

moriarti wrote:To my knowledge the Ks blocks have a special coating that lasts a lifetime, making Reboreing  not possible, the piston rings are made to were out rather than the bore. Some pistons have ring pins some dont. 

Hmph.  That is about as useful news as hole below the water-line.
The bores look like a VW Dune-buggy that has had a mouthful of grit, and what ever the special coating is, it doesn't look special any more.

I wonder, if when he opened it up and saw the damage, he was going to substitute the K100 engine, because all the parts seem to be there, but there are no injectors, starter or alternator among the 1100 parts. 
The poor old boy had a stroke about 20 years ago and that probably killed his plans.
I seem to have got answers the first day I'm here, to my initial questions, but not the ones that I'd hoped to hear.

If visible and within eyeshot, the easiest way to determine whether K11 or K12, is to look at the engine series/number on the right rear of the block, vertically stacked behind the sump fins.

K1100 are 112 followed by FA & engine sequential numbers, K12 are 124 followed by EA & engine sequential numbers.