I might be able to help, here is what I came up with:
CL350K4
Sell Date: 1972-73
Rel Date: 02/01/72
Product Code: 345 (Middle number of Honda part numbers)
Frame number: CL350-4000001
Engine number: CL350E-4000001
So the engine number does match up as a `72 K4 model.
Honda CB,CL,SL Carburetor Specifications:
Carb model 350A
Float level 19.mm
Std main jet #60 primary #115 secondary
Std slow jet #38
Idle mixture screw initial setting 3/4 turns from closed
Idle speed 1200rpm.
Carb model 3B & 3C
Float level 21.mm
Std main jet #70 primary #110 secondary
Std slow jet #35
Idle mixture screw initial setting 1 turn from closed
Idle speed 1200rpm
Carb model 3D, 722A, 726A, 728A
Float level 26.mm
Std main jet #68 primary (722A,726A) #70 primary (3D,728A)
Secondary #70 (3D,728A), #105 (3D, 722A, 726A)
Std slow jet#35
Idle mixture screw initial setting:
3/4 turn from closed (3D)
1 1/8 turns from closed (722A, 726A, 728A)
Idle speed 1200rpm.
NGK: B 8ES/ ND: W24ES Gap .028-.032in
Ign point gap .012-.016in
Ign Advance "F" 10º BTDC
Max advance 37º- 43º BTDC
Advance starts @ 1300rpm
Max advance 3900rpm
Dwell angle 105º (on 2 cylinder scale)
Condenser capacity 0.22 - 0.26 MFD
So according to this the 722A carbs are set at 26mm.