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Carb rebuilding bad practices |
Following is a description of just three things people do to carburetors they should not do. These things are very common.
Stroking throttles: If you look closely at the throttle plate of a Honda CV carburetor you'll notice the plate's edge is not machined at 90 degrees, it is at an oblique angle; it is in fact a knife edge. This angle accomodates the angle that the plate is itself mounted in the carburetor, so that the edge of the throttle plate seals perfectly against the carburetor body. And, the throttle plate is either brass or even softer aluminum. Dragging ANYTHING under the exquisitely-machined surface of the throttle plate is a really bad idea. Whether wire, or a plastic tie, drill bit, whatever, the throttle plate is not going to survive this nonsense without damage. The resulting groove scratched into the edge of the throttle plate will pass more air than the plate's position willl call for, throwing off everything--synchronization, idle speed, the works.
Burnishing float valve seats: A lot of advice on the 'net instructs to use an abrasive to "clean" float valve seats. I cringe every time I see it. The main problem with burnishing the float valve seat is it has the real potential of changing the shape of the carefully machined taper in the seat. That's bad enough, as the seats in many Honda carburetors are not replaceable and thus the carburetor body itself is ruined. How long is it going to be I wonder before folks stop doing this?
Using pliers on float pivot pins: Broken float pivot stantions are a fairly common finding on certain models of vintage Honda carburetors, when the previous mechanic has not been careful. Though obviously heavy corrosion around the part can lead to failure, even when there is not significant corrosion, the posts may still snap, if the pivot pin is not removed correctly. And correctly means with a properly fitting drift, not a pair of pliers. The use of pliers puts divits on the pin that make it seize in the posts, resulting in breakage of the posts during installation or more commonly, during a later removal.
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Last updated January 2025 Email me © 1996-2025 Mike Nixon |