I had always thought that the freewheeling feature was utilized to prevent excessive engine wear from oil starvation. Supposedly the two stroke would starve for oil causing cylinder wear if engine braked (off throttle) and that freewheeling was only to be dis-engaged for slippery conditions. Now, I could be totally wrong and was simply believing an old wives tale. As an incredible aside, we used to tow a TR3 to auto crosses with a '58 Saab 93. One of us would ride in the Triumph and steer, otherwise the rear wheels of the Saab would lift off the ground when rounding corners.