Cold Stumble

[GaTeach]

Has anyone cured the cold stumble?

[shooter]

Teach , I've never had it. I've heard others talk about it. I do have the Guhl flash but rode it three years before that. I mostly run Shell 93. Not trying to start that debate. If you haven't run any Lucas or Seafoam in the bike you might try that. I believe it's caused by a lean condition. A good cleaner might help. With your mileage have you had a set of plugs installed?

[GaTeach]

I haven't had new plugs. My mechanic thinks it's the fuel pump and they are replacing the fuel pump under warranty. (I don't think it's the fuel pump, but WTH, let them replace the fuel pump)

I've tried Seafoam.

Right now, I have to let her warm up to operating temp or else I get the stumble.

[53driver]

I think new plugs helped Isleen's stumble, but it's still there.
I'm getting an ECM to Guhl soon - too much performance going to waste in the name of the EPA.

While I'm waiting/getting the reflash, I'm going to run a full can of seafoam in the next 3 tankfuls just to ensure her pipes are clean.

It's embarrassing riding out of the driveway and have the bike buck and hiccup.....

[Sorcerer]

On my 13 I learned to start the bike, zip the jacket, put the helmet on, put the gloves on and at under 40-45* plug in the heated gear. The bike was sufficient to ride with some care. My 14 doesn’t have the cold stumble but does have an high idle for a short time. Longer when bellow 45-50*. I know, it’s not really a fix. My 13 had not so nice sounds coming from the clutch/ transmission at any temperature bellow 50* until it reached operating temperature.

[shooter]

I haven't had new plugs. My mechanic thinks it's the fuel pump and they are replacing the fuel pump under warranty. (I don't think it's the fuel pump, but WTH, let them replace the fuel pump)

I've tried Seafoam.

Right now, I have to let her warm up to operating temp or else I get the stumble.

Maybe not so much the pump as the in tank screen/ filter. I still think it's a lean condition , lack of fuel.

[53driver]

Maybe not so much the pump as the in tank screen/ filter. I still think it's a lean condition , lack of fuel.

If it's a screen or filter issue, why would it seemingly disappear at operating temperature?
I been chasing this one for 50,000 miles now....I'm ready to believe almost anything!

[olegoat345]

Stumble? guess I don't have one, 'cause I'm not sure what it is. I get a bit higher rev when I first start my bike, after a minute or 2 it's down to normal.

[shooter]

If it's a screen or filter issue, why would it seemingly disappear at operating temperature?
I been chasing this one for 50,000 miles now....I'm ready to believe almost anything!

Once the engine is warmed up it requires less fuel to operate efficiently.

[53driver]

Once the engine is warmed up it requires less fuel to operate efficiently.

Okay, I'm with you....but I'm still missing something (probably VERY basic):
Let's say that the motor requires "x" amount of fuel when at idle cold, and let's say needs "x/2" when idle warm.
When I crack the throttle at cold to get going - let's say that requires "2*x" of fuel - the motor hiccups almost to the point of stalling, regardless of clutch lever position.

If this was a screen or filter issue, would it then make sense that 'anytime' - warm or cold - I needed "2*x" amount of fuel the motor would at least burp?

Again, I am NOT being willfully ignorant here, I am just not getting it.
Thanks,
Steve