What would cause a 2006 Big Dog 117 C.I. to backfire all the time and break up at 3000 RPM's?

Question

At 70 miles per hour the bike sputters and back fires real bad. It's not water in the gas either and has new plugs in it also.

Answer 1

Possibly it is electric?  I'd investigate it as a problem with the ignition. I'd take it to the shop. Considering the price of these things, cost is not a consideration.

Answer 2

Ignition--Fuel mapping--Valve adj --sounds more like a fuel problem-pump filter ??

Answer 3

bad plug????? maybe

Answer 4

If you have fuel injection (doubt that) can't help you, but if your using a carb, go down 2 on the main jet, and move the needle ring down one to raise the needle and try it again, have you checked your plugs? run the h**l out of it, then hit the kill switch DO NOT LET IT IDLE, then pull your plugs out and ck the color, white or tan too lean, dark brown just right, black too rich.

Answer 5

Lotta guessing going on around here... That's an S&S motor with an S&S electronic single fire ignition set up at the factory to run right. Have there been any mods?. Get it on a dyno asap to diagnose properly.

Answer 6

Does it have a VOES on it? (vacum operated electrical switch). There usually located under the tank , where you can easily see it. Those engines , like HDs, have their timing change all at once( not gradually like a car) and it does it at  3K RPM. If the switch isn't working your timing will not advance. Hope that helps.