When I began doing carburetors full-time I tried using aftermarket float valves. They are 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. They wouldn't seal. 1 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 overflow. 2 Or the valves would fit poorly, too small in diameter or too long, both causing issues. 3 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 others.
Most folks know I try to concentrate on just Hondas. One reason is I like rebuilding carburetors for machines I am the most familiar with. That is, I know 70s and 80s Hondas well and I like to think about these bikes as I do the carbs, knowing where their weak points are and how in some cases they can be overcome with small carb changes. 4 The second reason I concentrate on Honda carburetors is they are the only brand factory float valves can be got for now. Later Kawasakis used the same brand of carbs as Honda and the float valves mostly interchange so I do a lot of those Kawasaki carburetors too. But if I can't get factory float valves for a carb set I won't rebuild the carbs. I won't make excuses. This is why I don't do older Kawasakis, Yamahas and Suzukis. There are no float valves left for these.
Someday I know Honda and Kawasaki will also stop selling their float valves, and I'll have to either stop rebuilding carburetors or start using crap float valves and making excuses to my customers. But I don't want to do that. What a terrible thing to have to do. And it's got me thinking. Why aren't the rebuilders who use K&L and other float valves making such excuses? Why aren't their customers being warned that the carbs could overflow at any time? It's perplexing to me. Maybe most customers fail to maintain their carbs from one season to the next (many do), and thus they never realize the poor quality parts that are in there, chalking up eventual leaking issues to "it's time to rebuild them again." And it's even more likely these rebuilders just don't care.
These bad float valves are often found in rebuild kits. I don't know if other forums have compared carburetor rebuild kits. If so, not many I'm thinking. Recently, I looked NGW's carb kit comparo over again. It's fun and informative, and I hope it instructs as instruction is badly needed. And I really appreciate the trouble that went into the article. But here's something I have to say. Putting carb kits up for comparison is like having a farting contest. The problem is the subject is still a fart. There is nothing good about carb rebuild kits.
For the life of me I cannot figure out the average consumer's fascination with them. Maybe it's the influence of the car repair trade. I dunno. But I know this, people within the industry have avoided them for decades, using instead quality rebuild parts from legitimate sources, including Honda themselves. No reasonably competent carburetor rebuilder uses kits. 5 They're extremely cheaply made, and more importantly, frequently result in that supreme tragedy, the ignorant tossing of perfectly good and very difficult to find OEM jet needles and needle jets. I deal with this issue almost weekly, having to inform my customers of the presence of Chinese or "high performance" metering parts in their carbs and the cost to replace them with OEM. The problem is OEM is pretty expensive because it's available only by buying whole carburetor sets.
Carb kits are like McNuggets. 6 Aggressive advertising has put both firmly on the radar and inextricably embedded into the culture, but inversely and perversely relative to their quality. What power, commerce! Beware.
1. One hundred percent of all new factory Keihin float valves pass the vacuum test (compared with fifty percent at best with aftermarket valves). Every one. Steel or Viton. I tested them every day on every rebuild for over a year. I don't test OEM float valves any more.
2. Viton type aftermarket float valves are often plated, it's one easy way to spot them. I weight-compared OEM to these valves and discovered the aftermarket are twice as heavy. They must be made of zinc instead of aluminum. I assume the plating keeps the raw zinc from reacting with the atmosphere. This also explains why the plating peels quickly.
3. Many models of Hondas have non-adjustable floats. Using aftermarket float valves in these carbs results in leaned out circuits because the valves are longer than OEM.
4. You may think that approach is assumed, taken for granted. But I can tell you most, nearly all in fact, carb rebuilders out there are clueless about the bikes belonging to the carbs they work on. They know nothing about them. And a good percentage of these folks know very little or nothing even about motorcycles.
5. I don't include Randall's kits in this, they're not even kits. They are closer to the "packing sets" Honda used to sell. And very good, even after being dumbed down by Dime City.
6. I am disturbed by a reality that is defined by pervasive, insidious messaging, and in my field this is best typified by carburetor rebuild kits. Here again, it is the ubiquitousness, the mindless marketing saturation, which raises the worthless to the worshipped. And marketing is all it is. There is little that is substantiative about carb rebuild kits. If it weren't for these kits' unavoidable presence at every turn, their sellers would not be as successful as they are. Marketing is society's new reality. Welcome to carburetor McKits. There is an insidious belief that crap is quality, that the least real thing is the most real, *if* that thing is everywhere you look, if it looms large on the consciousness. McDonald's is a perfect example. You think this establishment's name is synonymous with restaurant because of its food? You think it's number one on the consumer radar because of its product? Really? There are more Subway restaurants than there are McDonald's.