Interfuse is right, the engine is the same as in the CB-1, identical situation as the B4 and Gsxr400.
a long time ago i did some research in these. Really bulletproof, the cams are not chain driven, but sprocket driven! In other words, you'll never need to readjust the cams, but if the sprockets go bad then it can be expensive.
i have a small movie of a cb1 on a dyno, veeery impressive
I'd take it too!