Hello Mark, I know this is an old thread but yes the 1000 will fit into the 750 chassis, you will have to use the 750 rear rocker cover, the rubber snorkels on the airbox need to come off and you need to use the 750 pipes to clear the bottom radiator, though having said that they are smaller diameter headers, so a custom set is the go. I was interested to stumble on this topic as I actually have a 750 chassis with a 1000 motor in it sitting in my workshop now waiting to be refurbished (it's looking pretty sad after sitting around a long time) I have also fitted a CBR1000 front end, wheel (17"), forks, brakes etc, and have grafted a Yamaha Thundercat rear wheel (5.00X17 rim)
