I have a 2000 Sporty 1200 with 20k miles. I put the last 2k miles on it and its been running decent. Every so often it would sputter from the pipes and backfire from the carb when down shifting. But ran great and started np.

After a half hour trip the bike started to bog when I hit the gas at lower rpms and then would backfire loud. I took the air filter off and cleaned it. There was some oil/fuel on the bottom side of the filter. Pulled the plugs and they look good. Sprayed some carb cleaner into the carb and it seemed to help for a few seconds but on the road it was the same with lack of low rpm power and when I punch it the bike bogs down and backfires loudly from the pipes soon after. But then it picks up power again and almost throws me off the bike. It will run fine then until I shift and hit the gas again and it bogs and backfires.

I plan to get new plugs and wires tomorrow since the connection areas had a little bit of rust. Other then that Im at a loss. The bike was just running great. The only thing I did was run some seafoam through it. I also added some oil but didnt over do it.

 

The carb probably needs to be cleaned out. This can not be done with fuel treatments. It probably needs seals/gaskets too. I've had similar problems on metric bikes and it always turned out to be fine red sand in the fuel bowls. Last time it happened I think I got bad gas.

 

New plugs seem to do the trick. The bike doesnt bog bad anymore. Still get the carb farts and kind of a sputter or multiple small backfires when down shifting/engine braking. Will have to pull the carb and go through it when I have time.

 

Cleaning the carb would be my first guess. Do you have any upgrades to your bike such as exhaust/AC? If you do, did you rejet and tune your bike after the upgrade? I had to learn the hard way, stranded in the middle of the desert of with no cell phone service. One of the worst experiences of my life....

 

Im not sure on the upgrades. This is my first Harley and have owned it for 2k miles? or so. Its giving me the carb farts and I am trying to follow the directions here for adjustments but cant seem to find any pics of where the screw or plug is on the carb. Any tips?

 

Pull the carb and rebuild it ... really not that difficult. You can buy a rebuild kit on Ebay for $15 bucks. Lots of threads on here regarding mixture settings once you get it back together.

 

I found the AF screw plug. Will order a carb rebuild kit and get to it. Havent rebuilt a carb since we worked on VW bugs 25 years ago. Will be interesting but am a little excited to break into it. Ive read a ton of threads here about the rebuild and tuning the carbs. I feel pretty confident!

Glad I found HDF. Very helpful info and people here. Thanks Guys!

 

Take your time and you will be fine. Biggest pita will be getting the throttle cables on / off. Not that bad but can be frustrating the 1st time.

 

Take your time, ask questions if you get stuck, and take lots of pics to share the future Sporty riders. Good luck.

 

Don't really have to worry about the plug and screw. That is only for the IDLE air/fuel mixture and really doesn't effect problem you are describing.