Mikuni 42 enrichener

My enrichener knob on my Mikuni 42 will not stay open. I pull it out to start cold and it just springs back to the warm position? Anyone have any ideas?

There is a adjustment thumb bolt on the backside of the enrichment knob, tighten this up and you should be ok, not too tight because then you won't be able to pull it out. I had the same problem on my Roadking.

Also...becareful not to tighen it to much. It is plastic and will crack if ya torque it to hard. Then ya have to buy a whole new cable assembly cuz HD doesn"t just sell just the nut.

Your service manual will tell ya how to adjust it. As a wise man on this forum always say's, "the service manual is the most important tool in your box.

Keep in mind the Mikuni cable does "not always" work the same as the Harley.
Mine is a pre 1990.


Go to website for further details but, here is a brief.

Mikuni American Corporation

HSR Choke Cable Installation Issues:

The HSR series carburetors use one of two possible choke cables: the stock Harley-Davidson cable (1990 and later) or the Mikuni cable. Mikuni designed the HSR to accept the Harley cable to save you money and because the stock cable works well. The Mikuni cable is furnished for those installations that do not start with an installed stock CV carburetor.

The majority of HSR42/45 installations use the Harley cable. Installation is simple when the installation instructions are followed, step by step. Those steps are:

1. Remove the stock Harley choke cable assembly.
2. Remove the spring and plunger from the stock cable.
3. Remove the Mikuni "Starter Nut" from the HSR.
4. Remove the Mikuni spring and plunger from the HSR.
5. Install the Mikuni spring and plunger on the Harley choke cable.
6. Install the Harley choke cable with the fitted Mikuni spring and plunger into the HSR carburetor.
7. DO NOT use the Mikuni Starter Nut; discard it.
8. DO NOT use the Harley spring or plunger; discard them.

There is no adjustment knob. Its not like the harley cable. I know what you are talking about but there is no knob. I built the bike from a kit and installed the carb right out of the box. No knob.

Sounds like you need parts. Did you lube the heck out of it? The detent may not be engaging.