Jan Merckx had a little Kawasaki KR-1S 250 two stroke, nice bike, does everything right, but he really needed something with a bit more grunt, problem was, he liked the little bike, buying something big and heavy just didn't seem right. Sounds like time for an engine swap, and after considering his options, he settled on the Suzuki SV650, a four stroke V-Twin, narrow enough to squeeze in between the rails, but of course, there's a little matter of that rear cylinder. Not to worry, Jan's a persistent fellow, and frames can be modified, so the project began.
Jan began fitting the engine with the aid of an old broken frame he had on hand, it fit, sure enough, but that rear cylinder meant the rear suspension was going to have to be completely redesigned, something to do with basic physics and objects trying to occupy the same space at the same time.
After all of the usual cutting, welding, milling and miscellaneous metal bending operations you would expect in a project like this, plus seven years of effort and a whole lot of dedication, Jan had his bike. There's a build thread on the KR-1S forum over in the UK and well worth a look. I won't even try to pick and choose among the build photos to show you in progress shots, there's a lot of them, so head over and see for yourself.
These projects are always great to see, a bike, an idea and a whole lot of persistence bring about something you can't buy anywhere and Jan can be justifiably proud of his work. Nice job!
Link: Kr-1S forum