That sure is a great looking machine you have there!! and could be a great investment if you continue to keep it as virtually unused..... It would be a shame to spoil it after having survived all this time as a museum piece.
I have a 92 MC21 in rothmans colours, its actually an SE with magteks so as Andy describes "a dab of paint and a rub with an oily rag)... but i ride it regularly, it goes like foook, attracts loads of attention and looks the bollocks..... but best of all I paid just over 4k for it and i can ride it without any worry or diminishing its value.....
I did have to rebuild the crank but I reckon you will have to too at some point in the near future... if it gets used that is....
Not a rant or a jibe, just a reminder that there are alternatives to sourcing rare unused expensive original SP's and its perfectly OK to go down that route....