do all 2-strokes do this?

Hi Guys,

I am running a ktm -50 motor with a centrifugal clutch, it has no sprag catch so it should freewheel when the wheel rpm exceeds the motor drive.
THe clutch begins engaging @ 4k rpm. The motor redlines @10.5k
The carb designed specifically for this motor, is adjusted fine and jetted properly.
I am using the proper gas octane and oil ratio.
I have an expansion chamber and a muffler...motor seems to have no trouble getting "on the pipe"

The problem is this:
when the bike is not moving, the idle is fine...about 2k rpm
However, when i get up to speed and attempt to coast, backing off on the throttle, letting the clutch disengage and the letting motor idle, the motor dies.
To keep the motor running at 20 mph, I must keep the throttle revving. The clutch does not seem to have to be driving the wheels and is at least partially if not fully disengaged. When the motor dies, it does so all at once...no sputtering...just dies like the kill switch was hit (i checked the wires, theyre fine too)
When this happens, I can also confirm that the clutch freewheels because although the motor is not running, the tire keeps spinning without resistance.
I can restart it without a problem. Its not seized. It just dies.


This also used to happen to me with my china girl using a SBP kackshaft and freewheel if i disengaged the clutch at speed, it also died.

How do i solve this? I know that this cant happen on the ktm dirt bike that the motor is designed for.

The idle adjustment on the carbuetor does that and if I raise it any more its revving too high and ,the cluch begins to engage @ idle

it runs fine at 20 mph with the throttle open,
it runs fine standing still at idle
it stalls when idling and coasting in neutral at 20 mph


...air flow?
...carb angle?
....voodoo?

blipping the throttle gives quick response with no bog....clean acceleration