There's a lot of carby threads around at the moment so I thought I'd ad one.

Can anyone tell me the differences between the following Hitachi carb models , the first is off a round port 1200 engine and the second is off a 120Y oval port 1200 engine.

DCG 306-4
D320 4H

DCG 706-5
6402H

I'm just wondering if they differ in jet size etc etc.

Does anyone know ????????

all carburetors differ in jet size. Every year, the 1200 carbs were jetted differently. Even in the same year the same carbs may be different, e.g. fitted to manual vs automatic, region, etc.

All the A-series engines to my knowledge use the 306 except the A10. Are you certain the marking is 706 and not 306?

For examples of jetting specifications for various A-series applications, see the end of the article Carb adjustment, troubleshooting, rebuild and inspection.