I found this on a web site and wondering why the hole needs to be drilled larger. The site did not explain, just one step in a modification process. Am hoping someone can explain.

On the bottom of the slide are two holes. The center hole is for the jet needle. The second hole is off center. This is the vacuum port (CV Carburetor Cutaway #4). This hole needs to be drilled to 1/8". Make sure this hole is a clean straight hole. Keep the shavings away from the rest of the carburetor. Remove any burrs that exist and clean the slide. Set the slide aside for now.

 

http://www.nightrider.com/biketech/h...s.htm#main_jet

This is a link to the site.

 

Drilling the hole was a popular theory for a while, but has pretty much been proven to create more problems than it cures. Same with using a lighter weight slide spring.

 

Thanks cHarley

 

Does anyone know if the rubber boot on the choke/mixture cable assembly has a crack in it will cause a vacuum leak? Could this cause the front cylinder to run leaner than the rear?