With another 6" of twine and barely more work, this could be a proper sailor's whip. Done right, it will last near forever. You can find the instructions in any old how-to-sail or marine knots book. I learned the whip when I was 10 and use it all the time. I don't use it here because 1) it never occurred to me, 2) I use waxed polyester twine which is much thinner and would take many more wraps than I have patience for and 3) I want black there like my bar tape. (And a permanent whip on very temporary bar tape seems kinda pointless, Got better things to do.) I do use quick and dirty whips all the time simply because they are so easy to do and are so useful.

Trick- buy very strong twine. Waxed helps. Tie bowline knots in each end. When finished, slip screwdrivers (or whatever; marlinespike was the traditional tool) into the bowlines and use as handles to pull the whip tight. As you pull tight, you can see the crossing of the lines you are pulling under the wraps. Make sure the crossing stays near the center as you pull tight. Done right, a rope ending in such a whip was expected to stay properly whipped through a hurricane in open ocean. (Failure and the rope unraveling could be one of those little things that add up to a very bad ending. Think - cell phones were still 200 years away. No radio. No search planes. Keeping things shipshape was life and death.) The whip on handlebar tape? Like on the Riviera for that knot!

Ben