Well I'm not having any luck. By the way I found a way to test them is to put them into a pot of hot water, the water will heat up the air inside and if they're leaking they'll bubble. I just can't get the other side sealed. I also can't find any replacements, is there anything aftermarket that will work? I think even if I could get this to seal with solder, it would eventually start leaking again.

 Hey I think I found it!

hvccycle.net/mikuni-brass-float-vm24-171-002-114/

I ordered the float from HVC cycle Sunday night, and with just standard shipping it arrived here Thursday morning, from Nebraska to Southern California. Also ran down to the local auto parts store and picked up a new O-ring for the carb flange (it's rated for gasoline). The old one was flat and getting hard. Runs great now!

  

If you hadn't said it runs great now, i'd have said you'll never get the bowl over that Oring--so what would i know lol. Good work. & great you can buy a float straight off. Good info to know for us.

That small o-ring is actually a Yamaha part. I also bought one just like it at the same local auto parts store that I bought the large flange o-ring at.

It really is running much better now. In fact it was idling a bit faster so I had to turn it down a bit. Also starts up easier.

Nice job, congrats!