Honda CB750 Sandcast

Carb Fuel T's.

42barab

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Not sure this is the correct place for this question, but I think it applies to sandcast through K2 carbs. 

I bought a set of 7A carbs supposedly taken off a 71 CB750K1.  While going through them, found some discrepancies.  First attached pic shows the fuel splitter T's from the 7A (1971) carbs.  One T takes two o-rings and one takes four, but both have 5 mm ID.  CMSNL schematic shows two o-rings per T up to K3.  Parts book for 1969 shows same.

Second pic shows T's from 7A on the left, and the T from 064A carbs (1973) on the right.  Again, the ID of the 7A is 5 mm, but the 064A ID is 4 mm.

I've read that the earlier (up to K2) 750's were faster than the later (K3 on), and that Honda learned and made adjustments.  So I'm thinking Honda reduced the ID on the later bikes and added two more orings to reduce leaks? 



My question is which is correct for the 7A - two or four o-rings per T?  More importantly, is 5 mm ID correct for the 7A?  What would be the effects if I use T's with a 4 mm ID?


42barab

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