I have been cycling the complete KVR some ten years ago. And I don't recall having any conflict with anyone on a motorcycle at that time. Maybe the trail got more popular in the meantime for motorized traffic.
One hour ago I booked flights to and from Canada for a three-month trip next summer and I would love to be back on the KVR again - this time on a KLR 650. I hope that a solution can be found that allows access for all kinds of traffic. And this shows again how proper behaviour of us potentially fast track users is! Unfortunately a few idiots can destroy it for many others.