I think you are putting your own spin on this. Every Harley I've ridden clunks into first. Occasionally they don't but it's typical. Many other bikes also clunk into gear. I don't think there is any "correct" about it; I think you would prefer that it not clunk but that doesn't mean your preference is correct.

 

I figured it out he's using left and right wrong Me thinks he is sittin' on the bike backwards

 

A Clunking noise is not good for anything with gears. When I talked to a dealer about the difference between a Super Glide & Street Glide he said they are different trannies. My Brothers Super Glide shifts a lot smoother than mine all the time? I am trying to get used to a mechanical device clunking. I was told all big HDs clunk by my service guy and always have? I have had bikes for the last 40 years & only my HD clunkes most of the time?

 

The ABS braking system is transparent - it only takes effect when there is a possibility of locking the wheels. In that event the brake is cycled rapidly - pulsed; to prevent lock up. You'd feel it in the pedal. Locking the rear wheel and then coming off the brake can toss you on your kiester PDQ - ABS might prevent it.

Most people will lock the rear wheel (sans ABS) in an emergency IMO.

There is no connection between the tranny and ABS; the tranny is constant mesh - the drum turns - the shift forks move the dogs which lock the selected gear to the shafts.

I say your technique might be the problem.

 

I think what you are experiencing is when you down shift while applying your rear brake is when you release the clutch your rear tire locks up momentarily .That engages the ABS causing the brake to pulsate. I have felt this on my bike. I have since wired my ABS through my Aux. switch and only turn it on when I see fit, rain or wet roads.

 

Interesting theory ........... a slipper clutch prevents the rear wheel from grabbing but sans similar the rear wheel could hop on downshifts. When this occurs, the ABS logic could be confused and engage controlled braking - for an instant.

You might have discovered a shortcoming.