Split header tanks eh ... I had a bust one as did WJB, its not too hard to replace and not too expensive, about £22, jusy need to be methodical with it as its a bit of a pain in the backside, tank off, airbox out, ignition barrel moved out of the way ...
but seeing as i managed it on my own, you should be fine ...
OPS as Desmondo says, happens to em all eventually .... mine last year in the Pyrenees, what joy the hairpins were with an oily rear ..
