Recently, my bike has developed a cough or sputter while warming up.

It doesn't usually stall (will sometimes), but it will cough and almost die.

I had carpal tunnel sugury so my brother pulled the backing plate for me and cleaned the IAC. I'm also going to replace the backing plate gasket, but don't really think that's it.

Added fresh fuel with a little bit of cleaner to help clean out the injectors if that is the problem.

AC is clean also. I have the Screamin' Eagle backing plate with K&N.

After warming up, the bike seems to be ok. Plugs are clean and we even swapped my brother's plugs and it still does it.

Any ideas or thoughts? Maybe the coil pack?

 

Sounds silly, but check your battery cable connections (both ends)

 

Not silly...was planning on doing that as well.

 

maybe the cold idle control (setting or connection)has a problem. I would think that an electrical problem would not stop once warmed up. My bike can have the same problem If I don't run it with the choke for about a minute or so.(I have a carb).

 

It sounds just like a carbed bike without the choke on when cold.

I have a PC and it's been dyno-tuned for a couple years now, but this is a recent problem.

Hope it's not the stator going out.

 

You may want to try pulling the PC and see if it still sputters, perhaps corrosion on one of its connectors? Maybe the air temp sensor is not telling the bike its cold?

 

Another sensor not sending the correct information would be the cylinder temp sensor. It may work okay a high temp but lost it's cold temp resistance.

 

Never even knew about that.

Do you know wherabout on the head it is? It must be small and I'd assume threaded into the head?

Just to clarify that when I say it sputters when cold out, that the outside temp is 70° or more.

 

The bike will run on the warm up cycle until engine temp sensor reads over 150 degrees F or so. Could be that the ECU thinks the engine is warm and doesn't supply the extra fuel or timing.... which you don't need when warm.

Doesn't the coil pack usually fail warm, and runs OK cold?

 

That's what I thought, cuz It would miss, and sputter until it got warm, I figured no way it's a loose connection,so I bought a new ignition and coil, and had the same problem. I just by chance happened to have my bag off, and see that the positive was tilted (I always line things up when I tighten them) Tightened it up an VIOLA. Of course it came loose again, damn insert was half stripped. New AGM Battery now, and no more sputter (after she warms up at cold start, I start with enrichener full on, and twist the throttle twice, then engage the all ***** starter, after about 30 seconds I go to half enrichener in warm weather, or when revs start climbing, then in a minute or so she's warm enough to hold an idle)