kickdown issues

I think that patience will pay off in this case. Adjust , drive, adjust, drive and repeat until the shift points are correct for throttle position.

I had some trouble setting mine the way it "felt" right when I did the bbd swap and I had the factory linkage. A little goes a long way.
Just a hair too far forward will give you the no down shift condition. The total distance between no downshift and late upshift was only about 1/8 inch on my 904. I even had to tweak the bar to get the adjustment where it was correct.
I'd suggest to err on the side of late upshift then work your way to the proper position , cudadude is right on ...no downshift is a trans killer in short order.

Don't quote me on this but I think the factory adjustment procedure is to:
1. verify the throttle is completely closed when the pedal is released.
2. push the kickdown lever on the trans all the way forward and tighten.