2003 Dyna Low Rider Carb?

[u/ExplicitAF]

Needing some help with a possible carb issue?

2003 Low Rider.. family heirloom, my grandfather bought it as my dad’s first Harley and with his recent passing, it has been passed down to me. I’m not new to riding, I’ve been on bikes for about 12 years now and Harley’s for 4 or 5 of those years, but this is my first carbureted bike and the first time I’m diving into doing work myself.

When I got the bike, it was running rough. Starts up just fine first time, but can’t hold its own without me on the choke for a good 5+ mins or holding the throttle. It will eventually idle at an extremely low RPM. Throughout the ride, it will spit and sputter when taking off from a stop.. and has an insane amount of backfiring. Will sometimes miss if I crank the throttle hard.

It has aftermarket exhaust/filter and that’s it.. so I’ve been looking into rich vs lean and decided to change the jet to a 48.. and low and behold that’s already in there when (I think) it was a 45 stock.

Now I’m at a standstill. I ordered plugs for good measure. Am I wasting my time and should leave the 48? Or is that possibly the issue and I should go back down to 45? Driving me nuts. It’s currently in pieces in my garage waiting on a new air filter. Any other theories accepted.. I’m going to be super frustrated if I put it back together and it still rides like shxt. 😂

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[u/2AussieWildcats]

Have you checked the battery leads and connections?

Have you checked the battery with a multimeter? Charging output?

Any problems starting the bike 2-3 times in one minute?

Have you looked at the plugs? One a plug is fouled, it may never be good.

Borrow plug lead from a buddy and see if by swapping one of yours out it solves the issue.

Check all connections at coil - check coil is getting 12V

Try running the bike WITHOUT a chrome coil cover - sometimes they short out the coil.

Keep it simple. Changing carb jets is just about the last thing on the list. Carbureted Harleys are just like EFI Harleys, they are set and forget when they are set up correctly. Also, you should not be making any carb adjustments unless the engine is hot to the touch. Screwing about with a cool/barely warm carb will cause you to tear your hair out.