Your worried about 50hz flicker at idle ?
I wouldn't have written what I did if I didn't have valid reasons to be concerned that it might be an issue with these bulbs on the road when operated on the AC from an E.T.'s lighting coils. However, rather than a pointless data-free argument now, wait until measurements provide the answer. Whether or not there are issues depends on if the phosphors used to make the light from these bulbs white(ish) have decay times >5 ms and/or the characteristics of the electrical circuitry the drives the bulb. It requires measurements to know.
Meanwhile, if someone wants to try one of these bulbs in their E.T. bike before I find the time to make the measurements, it's important is to test it on a dark, moonless night. It's under those conditions where stroboscopic effects, if any, will be most noticeable and most objectionable.