Here is a 39 minutes lecture by Donald Thomas. I highly recomend you have a look at it and if any questions, lettin me know.
https://youtu.be/7W_qgeHG7bw
My earlier statement:
Sonalyst analyzed the RPM's from the tape and found that the motorcycle with the stuck mike ran for approximately 2 min. 48 sec. mostly at 3000 RPM up to 12 sec before the last shot "impulse" for the HSCA placement. This would be way too fast for Mclain traveling with the motorcade down Main street coming to Houston.
From the relevant portion of the video:
"Now andybody whose acutally had a motorcycle knows that theres ever not a really good correlation, but, never the less its reasonable to say that the motorcycle is humming along here"
This does not even attempt to explain the problem. I can only assume he knows that it shatters the idea that Mclain is the one with the open mic. Did you have anything else?