| 1975 1982 20R Cylinder Head |
| Round Intake Port /
Round Exhaust Port |
| 80 / 81cc Chamber |
| In. Valve Dia. 43mm /
Ex. Valve Dia. 35mm |
|
| 1981 / 84 22R / RE Cylinder
Head |
| Square Intake Port /
Round Exhaust Port |
| 82 /83 cc Chamber |
| In. Valve Dia. 44.5mm
/ Ex. Valve Dia. 36.5mm |
|
| 1985 / 95 22R / RE Cylinder
Head |
| Square Intake Port /
Pear Shaped Exhaust Port |
| 58 cc Chamber or
22RET (Turbo) |
| In. Valve Dia. 44.5mm
/ Ex Valve Dia. 36.5mm |
| |