hi Jo !
Welcome to Wiltshire Bikers! 8-)

"470 four" forumname..(.Darren is his real name) is the only member of WB that I know of who rides a (Highly modified) 400 four.
He's upgraded it, somehow!! (I'm not a mechanic!) by fitting a Yoshimura thingy, and it's now 470cc, goes like stink!! lol.
Hope to meet you at a meet or rideout very soon!!