At a loss for carb jet sizing??
At a loss for carb jet sizing??
Guys I'm scratching my head with this one. 2005 Road King carb stock 88 motor. So previous owner installed some DynoJet mods and had pilot jet 48 and main 180 in a DynoJet tube it looks like. Anyways I was getting really bad carb back firing. I have an Arlen Ness open big sucker (he had a hypercharger) on before. So I cranked out the air screw 3.5 turns and that nearly eliminated that. Fast forward to now. I put some ebay megaphone on stock headers and I'm now getting really bad decel pop like really bad. It away when I pull the choke out. So ok it's a lean pilot jet....but I'm already at a 48!! Also get a bog and cut out feel in 4 and 5 gear like it's hesitations to go for a second. Tempted to put in a 50/185 combo and air screw out 2.5 turns. Next week I'm putting on a fullsac true dual kit too.
Stellar HDF Member
Joined: Apr 2008
Posts: 3,002
Likes: 86
From: Charlotte Metro
The 48 & 180 was what my old '02 Fatboy had & I think that was the popular combo for stage 1. Your plug looks pretty good. I've got my original Dynojet jet kit if you want to experiment I'll ship to you for $15.
https://www.hdforums.com/forum/multi...9604-00-a.html
https://www.hdforums.com/forum/multi...9604-00-a.html
Thanks guys. Forgot to mention I have the old dyno jet kit from previous owner. Many main jets in there but no pilot. I can run to harley for new pilot jets. Looks like he swapped the spring and needle out. Looks like the old ones are in the kit. I'll have to run out and pop the cover off the carb to see what needle is in there.
Supporter
Joined: Jan 2007
Posts: 15,788
Likes: 5,625
From: along the shore of Mishigami
Here's some research for you. Search Joe Minton Carb tuning. I set my carb up like his article suggested and never a problem. Here's the catch, you will have to put your carb to stock, stock slide and back to a #45 slow jet, my 02 Dyna had a 190 main.
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Tourer
Joined: Mar 2014
Posts: 351
Likes: 0
From: Colorado
I agree with Joe Minton's tuning. My Evo Electra Glide had the Dyno Jet setup. I changed back to stock parts, ran an older Sportster needle, 46 slow and a 165 main. The bike rand great and got 42-48 mpg. You may have already done this, but change the rubber boots where the intake mounts to the heads, these will crack and cause a lean condition. A friend of mine runs the same setup on his 2006 Street Glide. In my opinion the CV carb is very good.
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Cool thanks guys going back to OEM Harley jets I think is key. I'm wondering if the pilot jet in there was Harley or not. It has some type of what almost looks like a star on it. Same with a 190 main jet that was inside what looks like a stock emultion tube that was in the used kit from previous owner. The new DJ jets in the kit only have a number on them. Also a DJ jet like a 180 is not a "true" 180 like a oem 180 from harley would act right?
Ok went back to garage pulled the DJ needle out it had the clip on the 4th spot down from top. Put the stock needle back in and also stock main tube and inside it was a 190 main jet. Heading to dealer tomorrow to get a sportster needle if they have it or I'll shim my stock one. Pilot jet I'm thinking a 46...main not sure 185 maybe? I'm thinking when I add the true dual fullsac to my already free flowing megaphones it might need the bigger jets. Plus my big sucker a.c. .....it's still odd to me with the 48 pilot and the air screw out 3.5 turns it was still decel popping like mad plus a rare carb fart. Lets hope back to harley parts and ditching the DJ parts helps get things back to normal....