Idles fine then dies when accelerating...

[bahiano]

Dear all,

just put a 72cc kit on my 4 Stroke Super 8. I changed the main jet to a 88 and took out the Air Box constriction.
It ran perfectly for about one hour test drive and then all of a sudden while driving it died.
I started again and it runs fine, but when i accelerate just a bit it dies again.
Spark plug look quite black.
My scoot is quite new and run about 2000 KM
What i checked so far:
Carb complete, including all membranes
Valve clearance checked
Zylinder Head Gasket
Intake Manifold no leackage
Compression
Vacuum tube for leackage
Spark looks ok (blue)

Plans:
CDI ordered for testing
New High Tension coil for testing
New Carb ordered for testing

If that also fails, i am truly out of ideas, maybe anyone had the same problem and the solution
is something completely different...

Thanks and regards from germany,

Markus

[spidrgr]

Dark plug: too cold. Usually, too rich a mixture for the plug temperature range. Go the easy way first and try a warmer plug. Otherwise, go down on the jet size. You say you have a 88. Try a 85 or even a 82.

[bahiano]

Thanks, today also my new Carb arrived, i will test it later...

Cheers Markus

[bahiano]

Ok folks, changed the complete Carb and it runs smoothly... cleaning the old carb did not help a  lot in this case...
Now finally i will enjoy my 72cc