Features And Benefits; Crankcase And Cylinders - Yamaha Z300A Supplementary Service Manual

Features and benefits

Crankcase and cylinders

The following modifications have been adopted to increase the output as compared to the Z250
power unit.
• The material of the crankshaft has been changed to a high-grade clean steel
bility against stress.
• Wider exhaust ports with planed-off edges have been adopted and the exhaust timing has been
changed to reduce the exchange loss of the exhaust gas.
• Cooling water jackets have been incorporated to the crankcase to increase engine-cooling ability.
*1: Steel with decreased nonmetallic inclusion content
1 Crankshaft identification
Identification mark: 2 mm (0.079 in) punch mark
2 Exhaust port
3 Crankcase water jackets
È Water flow
6D03F1X
Identification / Features and benefits
(*1)
1
to increase dura-
4