Join Date: Sep 2001
Location: Aurora, CO USA 80013
You're going to have to do some serious research and measuring to make 100% sure that anything else other than a Ninja 750R motor will fit using the stock mounts. But here is what I do know for certain off the top of my head:
Your Ninja 750R was made for model years 1987-1990- obviously any of those will be a straight fit. I would think that it wouldn't be too hard and very cheap to find one of those.
Kawasaki introduced the ZX-7R in 1989. The ZX-7R engine was heavily based off of the Ninja 750R motor. So, the cases should be the same width. While the engine might fit dimensionally, the problem is that the 7R engine was wrapped up in an aluminum perimeter frame. Your 750R has a traditional steel downtube frame. The motor mounts are surely entirely different. Maybe with some fabrication, you could get a 1989-1992 ZX-7R engine in there. Another potential problem with this swap would be the fact that the ZX-7R engine, and almost any sportbike engine from 1990 on up, uses downdraft carbuerators instead of the sidedraft carbs on your 750R. This creates a major packaging problem in terms of airbox and gas tank location. (perhaps not such a big deal for a dragbike only application)
Kawasaki substantially improved the ZX-7R in 1993. I am not sure if the engine in the 93 on up bikes have a completely redesigned motor vs. the 89-92 bikes or not. I suspect not.
The 1994-1997 ZX-9R engine is based on the 1993 ZX-7R engine. As I understand it, the cases are the same. So, if you can fit a 1993+ ZX-7R engine, you should be able to fit a 94-97 ZX-9R motor as well.
"Fat, drunk, and stupid is no way to go through life son." - Vernon Wormer.- Dean, Faber College.