Dellorto jet 6mm 134

6 mm Dellorto jet. If the spark plug is grey or even white, the mixture is too lean (a larger jet must be fitted). Continuing to ride the vehicle in this condition may cause the engine to seize. If the spark plug is slightly reddish-brown, the mixture is ideal. If the spark plug is dark or even black, the mixture is too rich (a smaller jet must be fitted).