Been having the worst time trying to keep my 99 Sportster 883 running, every time I think I have the problem fixed it just seems to get worse and worse. So needless to say I need some help, advice, or at least a direction to be pointed in.

Let me start off explaining the issue from the beginning. When I first picked it up, I rode about an hour and a half home in 75degree weather with no issues that I could tell. Had to wait a couple weeks to get the title moved over, so at that time I repainted my tank swapped out the handlebars, and cables. As well as doing a tank lift and relocated the coil and ignition. Took it out and the first day it ran fine for the first 2 hours and then started surging and slightly bucking then stalled when I got to the next light. It would start back up but continue doing this until it cooled down and then would run fine again. We checked the VOES first, that tested good, but the problem continued. Everything pointed towards the ignition module which according to the original receipts was only about 2 years old. Either way we swapped out the ignition module and the coil in order to bring it back to the stock setup.
It ran fine for the first 42 miles and then started bucking again and completely died, this time it would only restart if the choke was out but even with that it only ran for about 100 feet and died again. I saw that the vacuum hose connected to the petcock was dry rotted and cracked so I replaced it and everything seemed fine the 40+ miles home including sitting in massive amounts of traffic.

Two days later I filled up at a gas station down the street and 4 miles later it started surging again while going down the highway then there was a loud backfire (first time it had ever done that), so I pulled off to the shoulder and shut it off. Checked that everything was still connected good and started riding back home. It made it, only stalling once, till I got about a mile and a half home, then it died completely. I tried to restart it and after trying for a while it finally started with the choke out made it about 100 feet again and then died and didn’t want to restart. We pushed it most of the way and then about a half mile from home I was able to get it started, again with the choke out which lasted till I made it into my driveway and then it died again.
I thought it could have been a bad tank of gas but I was riding with someone else that filled up the same time I did and had no issues. Plus later that same day I started it right up after it had sat for a couple hours and it ran fine when I tested it up and down the road. The only weird thing I noticed was at idle with the bike upright it sounded normal, same if you leaned right but when you leaned left it sounded like it stuttered for a second then continued to idle. Not sure that means anything I’m just at a loss right now.

I know this was incredibly long but I tried to put as much info in as possible hopefully someone out there has an idea of how it fix this? I just really want to ride, without frustration and more than 40 minutes.

 

Sorry to hear this...by the year I ASSume that it still has the carb?

Whether you trust the dealership or not, that would be my first place to go. I had some decel popping and backfires after making some modifications to my 2001 and only cost me 75$ for carb rejet and tune and now my bike works great.

Good luck.

 

Did you check the fuel filter and the petcock screen for debris?

Also, make certain you haven't pulled something into the intake.

 

I would take the carb apart and check for trash just for peace of mind, but your description seems to point more to the ignition.

 

I was thinking petcock screen too. I don't know much about Harley carbs but I know I've run into this on my dirt bikes over the years and it's turned out to be a clogged primary jet or a float sensor. Just food for thought.

 

You guys are awesome with all the replies. I really appreciate them all!!

I have a stage 1 kit on the bike, the carb was rejetted when it was put on by the previous owner. I'm not getting decel pops it was just one loud backfire, never happened before and hasn't happened since.

I just changed the ignition module and coil, is there another part of the ignition that would need to be checked beyond those two?

I was also thinking it could be a fuel screen clog or issue but when it died on the side of the road I pulled the air cleaner off and noticed as I tried to start it when I pulled the throttle fuel was shooting into the carb but it still wouldn't start. So not sure if that rules out a fuel screen clog or not.

Can anyone tell me the easiest way to check and see if the screen is clogged? And also is there a fuel filter on a 99 Sportster the service manual only shows a screen.

Thank you so much!!

 

I've always installed a clear view filter regardless. It's just a good measure for keeping crud out of the carb. You have to remember how a carb works. The vacuum pulls fuel into the bowl, so when you have the A/C off, you'll see some fuel shoot out of the primary because it's in the bowl. However, a clogged screen could keep the ability to fill the bowl during load because of the restriction on the flow, that doesn't mean it doesn't get fuel at all (although eventually could lead to that).

 

another issue may be a air leak

check the seal ring in between the carb and manifold

or just use the propane test - it will let ya know if its a leak

 

Best way to do this is by removing the gas tank and petcock. The screen will slide out when the petcock is removed, and can then be cleaned. Flush the tank by running fresh water through until all the debris is cleared. Drain as much water as you can from the tank, then use a shop vac to get the rest.