How many times have I left the woods early enough to see deer standing around my truck parked 200-300 hundred yards away ?
Too many times to believe they have a fear of scent associated with mechanical things.
How many times have I driven that truck past deer that just stood there with no or very little reaction whatsoever ?
On a daily basis, they accept both the sound and movement from it.
How many times have I busted deer when walking into a property both fast or slow, in darkness and daylight, trying to be silent and from a downwind position relative to where I expect them to be ?
Every time if they see me walking, no exceptions.
And lastly, how many times have I been busted while sitting motionless in a tree when a deer unexpectedly approaches from a downwind position ?
Every time with exceptions. When I practice great scent control and wearing clothing that has been treated by means of a self made Ozone Closet or tub with an Ozone unit attached.
While I have had some minor reaction to the Ozone scent on my clothing I have yet to see a deer react negatively. Once the smell is encountered they are curious at first, but go on with their normal routine within a minute or two, usually less.
My experience over years tells me that E-bikes are probably ok to use. Mechanical scent should not be a factor, they have no reason to fear it.
Sound will be accepted over time, just like driving a tractor in their presence. As long as you don't stop or get off while they are watching your golden.
And combining a great scent free cleanliness routine with Ozone treated clothing is about as good as one can do, imo.
Hunt your way and enjoy it, deer are not stupid animals but sometimes we give them far more credit than they deserve, they adapt as necessary living near or far from human activity. Their reactions to your presence will tell you what you can or can not do, nothing more and nothing less.