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2006 Street Glide Carb Question

I have the same setup as you except I have True Dual open exhaust and n21 cams on my 05 electra with carb. Decel popping can be caused by overly rich condition. Too lean condition causes stumbling with hard acceleration from a stop. With my mods I am running a 48 slow jet ( 3 turns out from bottom) and factory main jet ( not sure what size, it's never been changed). My bike runs great and get 46 mpg. with perfect color plugs and light chocolate colored exhaust tips.
I think when you make mods they come in groups. If you open the breather, you have to open the exhaust etc.

With your setup a 48 slow jet should be the max, you could probably get away with a 46 and factory size main. Good Luck.
 
scrappyjack said:
Shouldn't the mixture screw effect the idle? in my case, the idle never seems to change when I go in or out with the mixture screw.
The transfer ports are fed from the pilot jet well. There is an idle air bleed that mixes with this fuel and provides the mixture to the transfer ports and the idle hole. The idle hole is closed off by screwing in the mixture screw, air at idle is of course adjusted by the idle speed screw. If you have decel popping you can do 3 things, increase the pilot jet size, turn out the idle mixture screw or change your exhaust to provide more back pressure and let in less air up the pipe.

Tuniig a CV carb is a sequential process; idle, mid-range and WOT in that order. Sounds like you are stuck at the first step. First thing to check is the A/F screw; remove it to check if the spring and o-ring are still there? If not, replace them. If all is OK, turn the screw clockwise and gently seat the screw closing off the air supply to the transfer ports. The motor should stumble and you will have to open the throttle a bit to maintain an idle speed of 900-1000 rpms. Back the A/F screw out until the motor appears to be running smoothly. If the motor dies when the A/F screw is seated, the pilot jet is too big. If you have to go more than 4 turns out and the motor still idles rough, the pilot jet is too small. I am thinking a 46 pilot might be where you need to be. Check out CV Performance for OEM CV replacement parts. Their A/F adjusting screw is a handy little piece of hardware.

Harley carburetor parts from CV Performance

If you cannot achieve a smooth idle following this procedure, then the transfer ports may be clogged or there may be some crud in the A/F screw bore.

Next is the mid-range. A stage I upgrade such as yours with slipon mufflers and hi-flow air filter should have the stock needle raised about .050". You can buy thin SS or brass washers that are .025" thick specifically made for this purpose.

Jets R Us Needle shim most Keihin 3.2mm I.D. x 7mm O.D. x .020†(0.5mm) thick 009-396

You first try the 46 with the needle in the stock position; then raised .025"; and try the 45 with the needle raised .050". Whichever seems to run the best is the place to leave the mid-range.

WOT is next but the 195 should be more than adequate; might even be able to run a 190 but the best way to tell for sure is to get idle and mid range as close as possible and get the bike on a dyno to check partial throttle and mid range.

Once you get the carb jetted properly, you can start to address the decal popping issue. As someone has previously asked, do the mufflers still have their baffles? Have the baffles been drilled? Why do I ask? Ever heard a drag bike with drag pipes or a moto GP bike as they decelerate? If so, you will recall lots of nasty decal popping. Those motors are in a high state of tune to run at high rpms with very little or no exhaust back pressure which will generate decal popping. Cool on the race track but not so much anywhere else. Could be that simply adding some torque cones to your mufflers to increase back pressure will help with the popping.

Of course, checking for intake and exhaust leaks and eliminating them is the first order of business before tuning the carb. Additionally, I recommend looking for a dyno tuner in your area that will do a few pulls to check AFR so you know what's going on. You need to remember that tuning the carb and the decal popping may be two completely separate issues and if conflated, you will be going down a rabbit hole, frustrated and not likely to solve the problem. It will take time, patience and a methodical approach to finding the solution. Good luck.:coffee
 
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