Sportster xl883c coughs while riding

Hi,
I have a 2006 Sportster XL883C, while riding at say 100km/h, the bike starting to cough, almost like backfiring continuously while you ride. also when bike is hot, it coughs when you pull away.

Danie
South Africa

Hello Danie and Welcome to Bike Talk. I think we need to clarify something first. Is your bike coughing (backfiring) right away or only when you get up to say 100km/h? How is your bike when it is cold ((running temp)?

Does the bike have any performance modifications or is it completely stock? Is the problem worse in humid conditions? Has it been getting worse? Has it had this problem since you bought it or did it occur all at once? Might be as simple as old sparkplugs or a bad tank of gas.

Thanks for all the replies.
Firstly, I bought this bike as used with 10 000km on the clock. It has screaming Eagle II exhausts. For the rest it is still standard.
The bike suddenly struggled to reach 100km/h, so I took it in to my local HD dealer. The conclusion was that air filter needed to be changed and my exhaust hasn't got back pressure. They put back on the original exhausts and I took it for a ride and power was good, but I don't like the soft sound. They put the Exhaust back on and that is when the trouble starts.
Firstly the rear exhaust does not idle the same as the front, making a wooh-wooh sound. After riding a while the backfire (cough) started when pulling away (it happened in front of the technician when bike was at normal temp). They said that they do this sometimes. Then it started to backfire while riding and power in fourth and fifth aren't the same, in fifth max 110km/h with down gearing to 4th gear with slightest uphill - flat out. Another thing happened when I was trying to start it again. There was no power (no lights on Speedo)when ignition was turned on. We wiggled the ignition and the lights came on. My friends told me the wiring is something wrong that is maybe also why it is Backfiring while riding. I don't know.
Please help.

With that info it sounds to me like it has an intermittent ignition coil failure. I would likely start with replacing the sparkplugs (cheap to buy)and setting their gap to spec. Also do not forget with the freer flowing exhaust you will need to rejet the carb for optimum operation. See if the plugs removed look similar or is one brownish while the other is black and fouled? This is just my opinion. Opinions are like buttholes, everybody has one.

Do you think heat or distance is the problem? They both run very close to each other, possibly try to see if you have good fuel flow from tank when it acts up. Maybe filter / strainer in tank loades up after a short distance. PLEASE be careful net to set yourself or hot bike on fire.

Probably the coil or loose connection somewhere. Sometimes coughing can be caused by a lean condition.

Yep, mine still coughin n fartin, just now on deceleration once in a blue moon, seems worse when air is colder out. I've learned to live with it.

No not all Sporty's cough and spit. I am not using any MoCo parts in my cv and this thing has never ran better. I would lean towards an ignition issue myself so I would check that. To answer one of the OP's questions, there is a pick up that is under the cam cover that is covered in resin. When that gets really hot it will melt and cause what it is that yo are experiencing, then once it cools down, then your bike will run normally again. Just a thought. A friend of mine said this to me, "when you think it is fuel related, check spark, when you think that it is spark related, check fuel."

Ha, Ha, a Baggerpaul quote I remember from a previous post! I have spent so much time and money this year chasing this cough and buying accessories, need to cool my heels and wallet until I park the bike in a few weeks for the winter. Then I'll pursue it again. Thanks for the tips, sorry for Thread Hijack!

One thing that most people forget about is that Sportsters are notorious as well for a dead spot in the throttle position. One of the first things that I was taught to look at was the accelerator pump diaphragm. Check that too.

I do not think that this is fuel related though, but it does not hurt to go through the checks. Another thing that the OP mentioned is that it happens when it wet (raining), if were fuel it would happen all the time in all conditions. Just an observation.

Oooppps, I am seeing stuff, hey, I had just got home from work. grrr