Tinker Talk – June 2019: Broken Carburetor Fuel Inlet Replacement

By Justin James

Nearly all OEM H-D Keihin carburetors from 1970 to 2006, and many other large bore Keihin carburetors, are equipped with a plastic/brass fuel inlet. This piece of junk will eventually leak or break. Unfortunately, many people fail when trying to repair or replace the inlet and end up replacing the entire carb. Over the years I have seen many unsuccessful attempts at repairing or replacing these. I am about to show you a method I have used countless times and that has never failed me, to remove these pressed in barbs. This method has even worked when the barb is broken off flush with the carb body.

Note: This procedure is to be completed with the carb removed. Due to varying mounting configurations, the removal of the carb is not shown in this demonstration.

Step 1: If the plastic part of the inlet is not already separated from the brass, you will need to do so (Photo 1). Vise grips can be used to shatter the plastic. Just clamp them on and gently rock from side to side. It shouldn’t take much force to snap the plastic off.

Step 2: Drill the brass barb out using a 7/32” drill bit (Photo 2A). Be sure to drill straight and do not drill in too far. Try not to drill further than about ¾” into the barb. You can place a stop on the drill bit to ensure you do not go too far in (Photo 2B).

Step 3: Cut threads into the barb with a 1/4”-20 tap (Photo 3A). It is best to do this by hand. Run the tap straight inward (clockwise) until the first couple of threads are cut. Continue turning the tap 1/2 turn in, then 1/4 turn out, until you have tapped about ¾” into the barb. As you approach the end of the depth you drilled to, the tap will become difficult to turn. When you reach this point, unthread the tap (Photo 3B).

Step 4: You may need to deburr the outside edges of the barb (Photo 4) to accommodate the pulling “tool” that will be slipped over it.

Step 5: Set up a pulling tool using a ¼”-20 bolt that is about 1” long (underhead), a ¼” washer and a 3/8” or ½” spacer that is about 1” long in the configuration shown (Photo 5A).The spacer will slip over the barb, place the washer at the end and thread the bolt into the barb until it seats (Photo 5B). Continue threading the bolt inward until the barb is pulled from the carb body (Photos 5C and 5D).

If you can drill and tap, this method will work like a charm every single time. After you have successfully made the extraction it would be wise to clean the carb before installing a new inlet. Do not bother with another one of those plastic/brass engineering failures (Photo 6). Always replace it with a solid brass one (Photo 7). To install the new inlet simply set it at the desired angle and tap it in with a rubber mallet until it seats.

Tinker, Shred, Destroy, Repeat

-Justin James

(follow more of my Tinker shenanigans on Instagram @justinjamesmoto)

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