I have an issue I hope you fine folks can help with. I have a 2004 fatboy carbureted with V&H bigshots pipes. I have to run for a really long time with the choke out at least half way before the bike will run without it. Then sometimes I still can't the bike will stall just idling at a light. I am constantly adjusting the carb. What can I do to resolve this? I have had suggestion of replacing the CV with a Mikuni? any other least expensive options?

Thank you
Jon Kelley

 

I've got exactly the same problem on my '05 fat boy too. Help. Somebody! Help.
BA

 

Hey Guys,

I have an 04 Fat Boy (95 ci Kit, 251 midrange cam, SE airkit, V&H Big Shot Staggered - no baffles, forcing cones for backpressure). My carb is the Harley-endorsed Mikuni 42.

It runs well but can be finicky. To start it, I pull the enricher out, crank the throttle 4x (6x in winter), and then start button. It usually starts right up. I adjust the enricher just enough to keep it running (about a minute). I then let it idle about 2 minutes with the enricher pushed in all the way before take off. It can be finicky restarting if I turn it off before it is fully warmed up (has a tendency to flood).

Once warmed, I only need to hit the start button...if I crank the throttle it can flood and then be a pain to restart. Only a couple times did I stall at a light for no apparent reason.

Overall I'm happy with the carb. I wanted a carb...just old-school I guess. Also, I've heard you can adjust a carb if you have trouble running on the road due to climactic changes...can't do that with EFI...gotta take it to the shop...could mean an extra day wherever.

I don't think my carb is running optimally, I get an occassional backfire when starting the motor...otherwise it runs great. I plan to learn how to tweak it myself someday.

I like the Mikuni 42....there are other good aftermarket carbs as well that are better than stock.

If your running for a long time with the enricher out your plugs are probably fouled...check them out...they should be a light tan color. You may need to find a good wrench and adjust the carb for your set-up. Was your carb rejetted after adding the pipes or airkit?

Good luck

 

Jon,
You may have several situations going on with your bike. I am assuming that you already have an airbox kit on the bike, if you dont, I suggest you get one. Since you live in Virginia, I would suggest a .48 slow jet in the carb, and install a small #4 flat washer under your pilot needle approximately .030 to .040 thou thickness. Turn you air fuel mixture screw out about 2 1/2 turns and that should get you close.

 

The stock EFI should adjust to climatic/altitude changes by itself due to the MAP (Manifold Absolute Pressure) sensor and what ever else H-D has hung on it. I don't know what happens when a SERT or PCIII is installed as I haven't done any air/exhaust mods. My understanding is the 07 models come equipped with an O2 sensor that is supposed to take care of all mixture stuff (like automobile emissions systems).

I remember when you could set the breaker points on the old ignition systems with a match book cover, set the plugs with a dime and adjust the carb for all functions., and never had any problems.

.......I guess those were the days.........

 

Try adjusting your mixture like thugged said and adjust your idle up a bit as well... or have you already tried that??

 

Sorry, entered same thing twice......