Here's a photo from about 6 years ago when i owned my Kona Koa, it was a 17" one, burnt orange colour, maybe that'll give more of a clue as to whether yours is 16" or 17".
Thanks for interest Reluctant but I'd regret selling this frame I'm sure. It really is a lovely ride and a lovely colour although a bit faded and chipped but doesn't bother me at all.
Alright fellas yes the koa is mine ,sorry for being a bit crap at gettin back to everyone,had a bit of a busy weekend with the floods.It seems the frame must be a 20" i did ride it for a while before stripping it and it fitted me well (5ft 10) and was a loverly ride.I was intending to build it up with updated parts ,but then was offered a f800 caad5 at too good a price to turn down.But now having ridden the cannondale a few times ,i just cant get comfortable and have decided to keep the koa and sell the f800 frame,forks and stem.Sorry for messing you about guys.