On the left is a Bisson 6.4 CI (100cc) Twin with a single carb. On the right is a Sachs Dolmer 8.4 CI (140 cc) twin carb engine This is the D&B 3.7 CI (~62 cc) Gas Twin. This is a Ziroli F8F Bearcat with a 3W120B2(7 CI) Twin 120 cc (7 CI) Gas Twin engine