This particular range of Kawasakis, produced through the 70s, were rightly known as widowmakers, for good reason. The power band was very narrow and the power almost kicked in as if you were using a switch. It switched off just as dramatically as well, which could be frightening if you were adjusting revs in the middle of the corner! Coupled with that the handling was shocking so the overall package was quite a handful and not for the feint hearted.
I once borrowed a friends 250 two stroke Suzuki of the same period with similar characteristics and the first time I went round a roundabout with it I had to go round again because I couldn't get the thing to come upright for the exit!
The RD250 and 400 were a little bit more civilised but I often think the two stroke only really came of age when the LC250, "Elsie", came on the scene. They were really nice bikes.
I've always been a four stroke fan myself!