® Float Valves
This is from one of the commonly available, popular carb rebuild kits. Note the tip is ground off center. This is not unusual.

I have said much elsewhere on this site about aftermarket float valves, but the fact bears repeating: they're junk. I have tried them all and I am just not willing to have my customer experience a leaking scenario immediately on getting his carbs back. They are that bad.

There are two types of float valves found in the Keihin carbs I focus on. The older all-metal ones and the later Viton-tipped ones. The all-metal valves are used on pretty much all Keihins made before 1978, with the exception the GL1000 which has Viton valves. The problem with aftermarket all-metal float valves is twofold. First, they have a much rougher finish on the working end, the sealing tip, than do the factory parts. This means their ability to seal is compromised from the outset. Second, and more importantly, they are machined inconsistently, with easily half of them so badly machined their tips are actually off center and therefore will not seal. I vacuum tested them for years before giving up on them and fully fifty percent of them would not hold a gentle vacuum. This meant that to complete a four cylinder project I needed to buy at mininum eight valves, and often ten or twelve. Not much value there. As I say, junk.
This is a K&L float valve for later model Keihin carburetors. Note the chrome plating badly deteriorating.

Then the Viton valves sold for later model carbs. The ubiquitous aftermarket Viton valve is a very cheaply made zinc part that is chrome plated to overcome the obvious problem of the chemically reactive zinc material. The weight of this valve is exactly double the stock item, which itself sets up some issues, but the real problem is the chrome plating. The plating begins to fail after a short time, and peeling off contaminates the float valve. In addition, an uncomfortable percentage of these valves has their Viton tips attached off center, making them not seal as consistently as the factory part. Longevity is an issue also. Whereas the factory part has proven to last 20-30 years, the aftermarket zinc valves' Viton tips get hard faster and usually fail within 2-3 years.

All this to explain why I use only factory float valves in all cases except the odd Mikuni or similar carb for which I have no choice as the factory part is unavailable. On Keihins however, it is factory all the way. I basically absorb this extra cost, which is typically five times the cost of aftermarket valves, and you should know this when comparing prices advertised by various rebuilders.

So here's the deal. The float valves are the single most expensive part of your carburetor rebuild. Think about it. Don't mess around. Use the good stuff. Hold out for the good stuff. Insist on the good stuff. Don't settle for crap.

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