Question about 2003 Harley Davidson XL 1200 C Sportster Custom
Acts like it is out of time, back fires, also main lead to voltage regulator becomes hot at connector. 2003 xlc 1200 with screaming eagle 7500rpm module
Your choice of words is a bit confusing. "Backfire" is used in several different ways. It could mean that it's spitting back out of the carb or popping out the exhaust. But, let's try this.
Most of time when I hear complaints like this, the engine is spitting back through the carb. This is the most common problem and it's caused by one thing, the carb is running lean.
Now, the bikes come jetted very lean from the factory so that they meet EPA emissions standards. The way I usually fix this problem is to go up one size on the slow jet. The factory slow speed jet is usually a #42, and I install a #45. I also take the slide out so I can get to the needle. I lift the needle out of the slide and install a 3mm flat washer. A 3mm flat washer (flat washer for use on a 3mm bolt or screw) is about 0.023" thick. Install it by sliding in on the needle from the long end of the needle and then put the needle back in the slide. This raises the needle by the thickness of the washer enriching the mid-range mixture just slightly. This should cure your problem.
There is one other thing that can cause this problem, a bad accellerator pump. To check this, remove the air breather cover and the air filter element so you can see into the carb. Right in front of the carb you'll see a brass nozzle standing up. With the fuel turned on and the engine "OFF", twist the throttle to the wide open postion. You should see a stream of fuel squirt into the carb. If not, you need to replace you accellerator diaphragm.
As for the connector getting hot, this is usually caused by corrosion in the connector, You need to disconnect the connector and clean up the metal contacts in both ends of this. Then, put some "bulb grease", (yeah there is such a thing used on brake light bulbs and stuff to prevent corrosion) in the connector. Silicone grease will do the same thing. If left unattended to, you're going to lose the connector.
Posted on Jul 29, 2010
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Posted on Jan 02, 2017
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