Hitachi 306 Jet Size Confusion- 1200 vs B210

[Dguy210]

Could someone clear up some confusion I'm having over the jet sizes on the Hitachi carbs used in the 1200 and B210.  I've been told and seen several people mention that the main jets in the 1200 are larger than those of the B210 and if running an A14 carb on a 1200 or A12 carb on a B210 that you should swap the jets.

 

However, when I look at the jet size chart on the 1200 wiki it looks like the higher number jets are in the B210 (102-107/145-150) not the 1200 (95-98/135-140). So are these weird and just reverse ordered and the higher number is the smaller jet? This just seems unlikely based on what I've heard on jet sizing used for other Hitachi carbs. So what is the deal here? Are the 1200 carb jets bigger or smaller than the B210 carb jets?

 

So I pulled some jets from A12 carb and A14 carb to compare.

 

 

 

 

So what I want to do is use my nice rebuilt A14 carb on my A12. I have a A12 parts carb to pull from. So I know just swapping the jets should work. However, I know the secondary jet on the A12 is a bit undersized for power purposes so I'd like to bump it up a size or so to get a bit more out of the engine.

 

 

http://datsun1200.com/modules/mediawiki/index.php?title=Carburetor_Specifications

 

Primary Main Jet - North American Models Year Jet Size 1971 No. 98 1972 No. 97 1973 No. 95 1974 No. 104 1975-76 California No. 104 1975-76 No. 102 1977-78 California Manual Trans. No. 105 1977 No. 104 1978 California Manual Trans. No. 105 1978 No. 104 1978 Federal 5-speed No. 107
Secondary Main Jet Year Jet Size 1971 No. 135 1972-73 No. 140 1974 No. 145 1975 No. 150 1976 No. 145 1977-78 No. 145

 

[Dguy210]

So...no one has an answer? :confused: