For background blur try using 1/30 to 1/125 second in shutter priority mode and let the camera pick the f/stop. And see which one you like that retains bike sharpness.
Then track/center your subject as you pan through. and use focus tracking on center spot af only. And AS YOU PAN, you take a photograph.
This will cause a background blur streaking effect.
As you say, with the shutter lag as it is, it is a bit challenging..
Hope this helps somewhat