oy mr maybury, don't you start taking the rise out of cleckheaton's finest, i did more miles on my panther than all my other brit bikes put together. if you took off those great heavy mudguards, that huge tank and that quarter ton seat, replacing them with lighter items, the old 650 was good for 85 all day mind you, with the sidecar on it was a tad slower.
i loved mine to bits [several bits in the end!] see:

http://www.ozebook.com/120.htm

and no, that ain't me.
ade!