Backfiring... Not running right

[thebottle]

So I am depressed because my bike isn't running right. I took it for a short drive and it ran great then I let it sit and idle while I had a smoke and it just started running like **** after that for some reason.

It won't start unless I blip the throttle while I am turning it over and then I have to keep it at 2k RPMs to keep it running otherwise it will die. It also backfires intermittently at the lower RPMs before it dies but otherwise runs great at higher RPMs.

Plugs all look good and I checked all the lines to make sure none of them were kinked off. What would you guys recommend I check or do next?

[dbeardslee]

You might check your vacuum lines and caps, and make sure they're all in place.

[thebottle]

All the vacuum lines checked fine. I put seafoam in the tank and it still kept doing it. I put the charger on the battery for about 45min and went out there and it is running perfect again. Would a weak battery cause a problem with the engine like that?

[Ken Talbot]

When you get it running for a bit, check the temperature of the four headers. I'll bet you have two running cooler than the two others. Which two are cooler will help point to the problem.

An intermittent problem like you describe usually points me towards pick-up coil wires.

[thebottle]

So I went to start it up and it is running at idle but now when I go to take off it starts to choke out again. Very weird, I will check that next though, thanks.

[thebottle]

Yeah, I looked at the pickup coil wire and each of the four wires has 3 crimps in it and at least 2 spots on each wire where the copper is exposed. I pulled the wires away from the bike so it wasn't shorting out on anything and it started running great right away. I have no idea what kind of idiot makes that many connections in a wire. The turn signals and brake light were like that too, each wire had about 3-4 crimps in it for no reason. Thanks a lot for that tip. Have that fixed in no time.

[dpotter58]

Those damn pick up wires... I fought a hesitation under throttle then a backfire when letting off for a year. I thought it was a carb problem then I took it to see Mr. Wizard and he found the broken wire.
I gotta tell you, it had a very impressive backfire when that wire made the connection after letting of the throttle..