Q. Is it suitable for 5.4ft person - YZF R1?

I am 5’5” and have had an R1M for over a year. I cannot tippy toe both feet at once, but if you can shift your bum as you stop and use the rear brake for starting and stopping it is not a major issue. If I slide to one side I can place my left foot flat on the ground (right on rear brake). I’d suggest you are very comfortable with the above before buying one.

I don't know. Can you repeat the question

It's not suitable