www.nsu-quickly.de

I use the 12mm carb and the parmakit. And the 64 main jet, with the 66 main jet my quickly sputters and Four strokes.
I use Castrol semi synthetic Oil at 50:1 mix ratio.
My spark plug is not getting so Brown as people say it should so here is a picture so you can help decisions if it is normal.

Should I switch to mineral Oil and use a 33:1 ratio or 25:1 ratio instead? Or why could it be I think my plug is more gray than Brown?

As I Said the main jet should be the right one since the 66 jet Four strokes at full throttle on a flat Road, and the 64 main jet do not. The needle is in the 3. Notch.
Hope for help!

No one knows? Please help guys

It looks perfect, but it depends from the light too.

Just outside in a little Sun, I was just nervous that it was to Grey!
As I Said I have a 66 jet bought from krippl with that one my quickly Four strokes and sputters when it reaches full speed on a flat Road, I then took my 64 jet from krippl and there it do not Four stroke and sputter at full speed, so the main jet should be correct right???

What about the Oil? Is it ok to use semi synthetic Castrol Oil in a 50:1 mix ratio? I have the new crankshaft with a needle bearing and not the old one with the brass bearing.

Looking forward to hear from you.

And also would the new kind of Oil tend to not make the spark plug as brown as in the old days when there only was mineral Oil?