Am interesting exercise, but what was the point of it? A speedway Jawa would cost about the same as a TZ750 crank. If the AMA ever had any brains their guys would have been riding them instead of the garbage. I've still got the spare egli frame waiting for a TZ750 motor. One of the sidecar guys had one for sale for about $4000. Took it out in his sidecar and slotted the cases. We've obviously lost the plot!