I can't find any reference to a serial number starting with a K and then four numbers!
Many thanks
Those are Crespera lugs from 1967 to 1974 with matching badge
The OP's frame has much later decals, head badge and odd looking forks. A pic of the seat stays may help as the Flyer often had a really nice arrangement.
Thank you Mr Spokesman.
Shaun
Wouldn't the triple spoke chain wheel and extra levers on the Weinmann brakes point to it being an early 70's model. If the parts are original there should be a date stamp on the back of the brakes.
As you say it seems a bit of a mixture. The rear frame has got a bridge for centre pulls yet it has side pulls. Perhaps it is like my Carlton, a previous owner stripped and sold the bike as spares and somebody else put it back together with near period parts.To be honest it seems to be a complete mish mash. Grand Prix decals although not a Grand Prix. I'da previous owne to identify the frame as a starter for 10 and its age and then the fun can begin!!!