My U.S. seller Honda needles arrived. I have installed them, and they work great. I solved the needle height problem. The solution is incredibly simple.
This is gggGary's pic from the other thread. A little hard to see, but it shows the steep tang angle that the longer Honda needle requires.
I initially got a similar result. I am using the same Honda needle, purchased from the same eBay seller. The truth is, after bouncing the tang up and down on the needle a few times, I think that this is probably perfectly adequate. But, we can do a lot better than this with a very simple change.
My tang after the change. Much improved. The other float looked even better -- the tang was pretty much perfectly parallel to the float yoke.
There is a washer that sits under the valve seat, Yamaha part # 214-14195-00-00. Actually, my pic shows the MikesXS replacement washer, which is aluminum. The stock washer is red and I think is fiber.
Anyways, all you have to do is eliminate this washer, and now the height of the Honda needle will be correct.
In place of the washer, I used this. ThreeBond, Yamabond, Hondabond, Motoseal -- I believe that all of these grey, non-hardening gasket makers are the same, and whichever you have on hand will work. I know that Motoseal is intended for surfaces that press together, not for surfaces that rotate together, but nonetheless, for this application it is working.
If you want to get really compulsive, you can use Permatex PermaShield Fuel Resistant Gasket Dressing & Flange Sealant, part # 85420. It specifically mentions ethanol resistance.
I applied the Motoseal to the mating surface. You could also try thread sealant applied to the threads. Even LocTite might work. Or Yellow Teflon tape.
I don't have long-term results yet, but I think this is a winner. I will probably never buy a stock Mikuni BS38 float valve again. Partzilla currently sells ONE float valve for $16.31, and that's before shipping.
https://www.ebay.com/itm/192195452506
I used the above listing, and bought FOUR Honda needles for $12.95 plus tax, delivered. Needles from Asian sellers are even less.
Obviously, you have to re-use your old seat. Polish the seat's orifice bevel by chucking up a Q-tip that has a bit of metal polish on it in a drill motor. Also polish the wall of the bore.