I'm experiencing hesitation and mis-firing, a.k.a. sputtering, on my 2003 BMW R 1200 CL. What would cause this to happen?

SOURCE: spits sputters and backfires

carborator needs to be cleaned and the float needs to be reset

SOURCE: backfires thru carb.spits and hesitates

have you add anything or adjusted anything? spray some soapy water at the intake seals while the bike is running (idling) if the idle changes you have intake seal leak and if you have added an new air filter other than stock you may be running to lean and need to rejet

SOURCE: My 2003 sportster 1200 sputtered this morning and

Sounds like it ran out of gas. Yeah, and I bet the fuel tank is full. Reach under the fuel tank to the petcock and pull the fuel line off. If you've still got the vacuum operated petcock, no fuel should flow out. But, if you try to start the engine, the vacuum should open the petcock and allow fuel to flow to the carb. Press the start button and watch for fuel to run out, catch the fuel in some sort of container.

If no fuel runs out, you've got a bad petcock. I've seen this at least a hundred times. Those petcocks are the worst thing Harley ever did in my opinion. You can take the petcock out of the tank, disassemble it and look for a hole in the diaphragm or you can replace it with a high quality manually operated petcock. I recommend a Pingle. They're pricey but well worth the money.

To check your diaphragm, take the four small screws out of the back of the petcock. Remove the plate watching for the small spring and needle thats under the plate. Hold the diaphragm up to the light and gently stretch it and look for a hole. If you find a hole, buy a replacement diaphragm at your local Harley dealer and reassemble your petcock.

Hopefully, this will help you fix your problem. If not, write back and give me some more information.

Good Luck
steve

Testimonial: "This was the problem! Fixed it last night and it is running great! Thanks!!!"

SOURCE: 99 sportster motor 883 with

From what you describe, it sounds like it is running too lean.

SOURCE: 2003 fxstb bike will every so often will spit and

Ohh, that's hard to say what would cause this because there are so many things. It could be carb jetting, spark plugs, plug wires, trash or water in the fuel (especially a little water), or most anything. The problem is that since it only does it intermittantly, you'll just have to try a few things and see if it goes away.

The first thing I'd do is drain the tank and take the fuel petcock out. Check the screen and the vacuum diaphragm in the petcock. Take the four screws out of the back plate on the petcock and carefully take it apart. There is a needle, a spring,and a diaphragm in there. Hold the diaphragm up to the light and gently stretch it. Look for a hole. If you find a hole, replace the diaphragm. If not, make sure the petcock ports are clear of any debris and reassemble it.

When you put the fuel back in the tank, watch for water. Still, it's a good idea to buy a can of Sea Foam and add some to the fuel.

Good Luck
Steve