I have (had) and Goldberg Ulitmate bipe and it will KE spin, but it is not easy to start. In my experience you have to catch the sucker at just the right moment and add just the right control throw and power. Kinda hard to explain how I enter them but I'll try.

Climb straight up, power back to about 1/4 throttle like you are going to do a stall turn. On low rate elevator, low rate aileron and high rate rudder, perform a stall turn, but kick in down elevator and a bit of same side aileron at the same time... wait for it, you should just barely see the start of a KE spin developing. After about one rotation you should clearly see the plane is trying to do a KE spin but it just isn't fully developed yet. At this point add a little power and a little more throw to tighten the spin up. Once the KE spin develops, you can flip to high rates on all and goose the power... she should wind up into a real tight KE spin. I have found that if I hit power too soon or switch to high rates too soon the plane will fly out of the spin.