06 Road King running like crap. Pulled carb and intake and replaced the intake manifold seals and the carb seal. Cleaned up carb and jets. In doing that I found that the mixture screw was out about 3 3/4 turns! Guess previous owner making up for intake leaks (?). Found that the jets were 45 idle jet and a 180 main. Bike has always seemed to be running rich at idle. Fills up the garage with fuel smell while warming up.

Buttoned everything back up and went ahead and set mixture screw at 3 1/2 turns out. Bike runs so much better. But seems to running rich at idle. So, where is a good starting point for the mixture screw? I'm going to readjust it and start from there.

TIA for you help!

 

I'd probably go this route:

 

Put in bigger cams. Seems like more work, but it should be just right then.

 

It's been a long time since I touched a Harley carb but generally, with a warm engine, turn the mixture screw in until the engine starts to miss, then back it out 3/4 turn. Now you'll have to adjust for off-idle acceleration by blipping the throttle and ensuring the the engine doesn't miss or stumble when the engine is revved off-idle. You'll need to adjust this with the idle mixture screw, if the carb is jetted properly. I recommended the jet kit in an earlier post so that you'd know that the carb is correctly jetted.

 

Your jets sound reasonable, depending on intake and exhaust and cam and head work and all that.

Mixture screw sounds like it's a bit farther out than it wants to be. Try 2.5 or 3 turns and see how it responds.

 

Here's what's in my 02 FXD carb. #45 idle jet, 190 main, two #40 brass washers under the needle and mixture screw out about 2 1/4 to 2 1/2 turns. Google Joe Minton carb tuning. IMHO sounds like someone may have put a Dyno kit in the carb. If that's the case, put your carb all back to stock, and start over. Back when carbs were the norm there was a lot of chatter about the Dyno kits, more negative than positive.

 

My mixture screw was set to 3 1/2 turns too and it ran rich (32 mpg). Someone had put a Dyno needle in it . I put a stock style needle in, 48/175 jets, and I am getting 44-48 mpg with the mixture screw set to 2 1/2 turns. I would almost bet that someone has messed with your mid-range needle. Your current jets should work fine. Also, check the vacuum diaphragm on top of your carb for a pin-hole or split which would cause a vacuum leak. I had all kinds of runnability issues including jerking/surging under light throttle at around 20-30 mph, rich spark plugs, and of course poor fuel mileage. My bike runs absolutely perfect now.

 

I believe #45 is the stock pilot jet and running lean has always been the problem with these unless you have an air filter problem. So, first, check your air filter for clean and clear, get the engine Hot first, then adjust your air screw for the fastest idle speed. The adjustment is done with the engine running. keep your idle speed adjusted down until you find the sweet spot. then set the idle speed where you want it. There is no set it 3 turns and your dead on, all bikes are different. If you find your air screw is like 6 turns out, go up on the pilot jet, most run a #48 and start over. With the correct jet installed, you should be within the 1- 4 turns out range
I would stay away from the Dyna jet kits, they do cure the lean condition but you will be getting low mpg. Good Luck!

 

put a S&S E shorty on it ! bullet proof and wil run so much better.

 

I figured I'd add my 2 pennies... I have an 01, just put in SE204's, intake Exhaust. Everyone's bike is different so a set "turn this, put this jet in" doesn't always work. It might get you close, but for me to feel good about carb tweaking, I put a Wideband O2 sensor in to tune the carb. I don't know how many turns out I am on my idle needle. I do know that when my bike is cold with the choke out I idle at around 11.5:1 and when warm the bike idles around 14.5:1 so I'm happy. I put a couple washers in and ended up with a 46 pilot jet. Being new to carbs, this video helped understand a lot about how they work.

https://www.bing.com/videos/search?q...72&FORM=VRDGAR