Carb Issue
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Stage I
Joined: Jul 2006
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Carb Issue
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
Thank you
Jon Kelley
Tourer
Joined: Apr 2006
Posts: 440
Likes: 13
RE: Carb Issue
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
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
Novice
Joined: Jul 2006
Posts: 23
Likes: 0
From:
RE: Carb Issue
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.
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.
Tourer
Joined: Jul 2005
Posts: 422
Likes: 0
From: Brookville, Ohio
RE: Carb Issue
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.........
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.........
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