Valve flutter

[Ironheadmike]

98 Evo carbed . What causes valve flutter when you turn off the bike ? It's not dieseling .

[fbn ent]

I haven't ever heard the term valve flutter....

[kd]

I was afraid to ask too.    What kind of valve?

[Ironheadmike]

When I shut the bike down the valves are still opening and closing like the bike is still running . Like it's dieseling without any combustion . It does it for about 2-3 seconds .

[kd]

Possibly too high an idle or the throttle plate is open a bit at closed throttle. Could need a carb idle adjustment to set the idle circuit and get the plate closed.

[smoserx1]

When I shut the bike down the valves are still opening and closing like the bike is still running . Like it's dieseling without any combustion . It does it for about 2-3 seconds .

Still not sure what you are talking about.  The valves will still open and close until the engine stops rotating from its own inertia and the higher your idle is the longer it will rotate after you switch it off.  As for actual dieseling, my bike has done it a few times.  It is rare but happens occasionally.  That used to be a big problem with cars (especially ones with high compression way back when).  Companies attempted to solve it with anti-dieseling solenoids in the idle circuits of the carburetors.  Your bike  does not have this feature, so it can happen.  Not an issue with EFI vehicles because when the electricity stops so does the fuel.

[wfolarry]

An oil burner will do that.

[kd]

   Especially if it can get air at a throttle off position.

[Thermodyne]

If the engine is turning over under its own power, and the ignition is off, Its dieseling.  Or running on compression ignition.

Lots of causes from smoldering carbon deposits, to misapplication of the throttle blade.  If it does it, but is running backwards, there is unburnt fuel in the exhaust.

First thin I would de is look at the throttle blade at idle, see how many transfer ports its pulling fuel out of.  More than the idle port, and you need to close the blade so as to cover the second port.  Thats why some throttle blades have a hole drilled in them, to bypass a little air.  Next, shut it off and see if you see fuel at any of the transfer ports.  You see fuel, and the is an issue with the float. 

If it turns out to be carbon, then try cleaning some of it out of the cylinders.  The spray stuff Chrys sells under the Mopar brand works as well as any I've used of late

[Ohio HD]

Run heavy concentration of SeaFoam in the fuel. Get the motor hot, ride it several hours. The run it hard several times to red line.

I've had great success with SeaFoam taking carbon out of the combustion chamber.

[Deye76]

Run heavy concentration of SeaFoam in the fuel. Get the motor hot, ride it several hours. The run it hard several times to red line.

I've had great success with SeaFoam taking carbon out of the combustion chamber.

This^
Also when the oil is hot at change time, fog the intake with Seafoam spray.