How to avoid vacuum leaks when installing a Harley-Davidson intake assembly (Part 1/2)

Watch Part 2 here: • How to avoid vacuum le...
Intake leaks may be present when a fully warmed-up engine will not run without the choke (enricher) and/or when idle is erratic.
When an angle finder is used to properly orient the carburetor/intake manifold assembly relative to the motor instead of H-D's induction-alignment bracket, the face of the carb has to be parallel to (be at the same angle as) the flat surfaces of the carburetor-bracket mounting bosses of the cylinder heads. When the motorcycle is UPRIGHT, both the face of the carburetor and the flat surfaces of the carburetor-bracket mounting bosses of the cylinder heads will be essentially vertical.
Harley Davidson HD H-D Evolution, Evo, Twin Cam, Sportster, Dyna, Softail, FXR, FXRS, FXRP, FXRT, Sturgis, FLH, carburetor alignment bracket, head breather, bottom breather, air cleaner

[@Zerk_Ziegler]

The main purpose of this video is to illustrate H-D's intent behind intake-tract alignment. For a more practical approach to this issue, please watch Part 2: kzbin.info/www/bejne/kHjCZYSDoNasn9k

[@andrewbassett2507]

Good quality how to,two thumbs up!

[@Zerk_Ziegler]

Thank you!

[@CAGraphics576]

Is there a substitute lubricant on the carb/manifold gasket? Perhaps lithium greece??

[@Zerk_Ziegler]

The lubricant I used in the video was for temporary installation only. Spit works just as well for that purpose. Lithium grease should work for the final install. But, EZ Turn Lubricant is the best lube for the application, in my opinion. It is expensive stuff, though.

[@davidkeeton6716]

The stupidity of a tool used to make sure that the carb is exactly upright on all axis. A motorcycle is almost never directly upright. So it shouldn't matter.

[@Zerk_Ziegler]

The primary purpose of the H-D factory tool is to square the intake-tract components with a plane, defined by the flat surfaces of the bracket-mounting bosses of the heads so that the manifold and the carburetor are aligned properly. In other words, the H-D tool is manufactured such that the surface of the tool that is in contact with the face of the carburetor is PARALLEL with a plane, in which the contact surfaces of the feet of the tool lie (the feet of the tool are intended to rest against the heads). The video was intended to show that some carburetor-mounting brackets are not precision made, resulting in less than optimal mating of the intake-tract components when the carburetor-support bracket is tightened down, which could potentially cause intake leaks. The goal is to set the face of the carb in a plane, parallel to the flat surfaces of the bracket-mounting bosses of the heads. As to leveling the carburetor in all directions, let's keep in mind that the carburetor is designed to work with the float bowl "level-ish", since fuel level affects how rich or lean the air-fuel mixture is. When the motorcycle leans left or right in the turns, the fuel in the bowl remains level (relative to the float bowl, not the ground) due to centrifugal force. However, problems can occur when the motorcycle pitches up or down too far in a vertical plane (when doing a wheelie, for example). Watch Part 2 for tips on how to install the intake manifold and carburetor without the H-D alignment tool.