Carburetor fuel level
Many believe that the specified float level on a Honda carburetor is what it is for the purpose of liquid tightness. They therefore proceed to alter that level when experiencing float bowl overflow in hopes of stopping it. There are literally dozens of possible causes of fuel leaking from the carburetor, enough to put them into two large and different categories even. But fuel (or float) level is way down on the list, for one important reason: high fuel levels result in richness throughout the carburetor’s entire operating range. If float level was to blame for your carburetor overflow, long before complaining of that you would have got off the bike in disgust due to its running so badly. Think about it. Don’t try to solve carburetor overflow by changing the float level. Fix the actual problem, which the most likely on old Honda carbs--after bad float valves--is cracked overflow standpipes.

The clear tube method
The clear tube method of determining fuel level often promoted on the Internet for use on vintage Hondas is one of a myriad of things online communities take out of context. Early examples of non-Honda (Mikuni) carburetors had inherently very leaky float valves, thus the OEMs that used Mikunis--Kawasaki for example—had to use a fuel level measuring method that accommodated their carbs’ “dynamic” fuel level (as opposed to its static level). Yamaha also had this problem. Look around for Yamaha triples or XS1100 fours. Not many to be found, are there? So bad were their float valves that their roller bearing crankshafts wore out ages ago, due to fuel dilution of their crankcase oil. Though advocated on many Honda forums, the clear hose method is irrelevant to Hondas. This is proven by the fact that the procedure has no reference point in connection with Hondas, no standard. That’s because Honda never published and never adopted this method. They didn't need to. Honda uses the simple float height method because their float valves don’t leak. Do your Honda float measurement the Honda way, using the Honda tool, and the Honda method (with the carbs right-side-up, as Honda's 1960s and early 1970s publications show). You can't go wrong. The clear hose method is not one that is universal, is not a technique for solving float bowl overflow, and is not superior to Honda’s float height method. The forums are wrong in characterizng it as a superior way to do the job. It isn't.

Float valves
When I began doing carburetors full-time I tried using aftermarket float valves. They were uniformly bad. I began testing brand-new ones right out of the package with a Mityvac before installing them. The result was I had to throw half of them away. I had to buy eight to get four that would seal. Sometimes ten. And then, more often than not, even the ones that sealed initially quit sealing after a short while. And if that didn't happen then the plating that is put on these crappy float valves would begin to peel, resulting in carburetor overflow. One hundred percent of all new factory Keihin float valves pass the vacuum test. Every one, steel or Viton. The first thing a carburetor customer looks for is fuel tightness. I'm going to send him carbs I know are going to leak? Hardly. I can't understand why anyone would use these parts, especially people who rebuild carburetors for a living.

The VB carburetor
The pilloried PD carburetor