Topic: Two different rotor shields for the 750?

[CycleRanger]

I have these two rotor splash shields.
The top one is from a 750K3.
The other one is from another year 750 or perhaps another bike.
Can anyone ID the bottom one? You can see it's a slightly different design.
It does fit my K3.
Did Honda change the design for the K7-8? Or is it from another bike?
It's the details that drive me crazy....

[754]

Keep in mind  550s used a smaller disc , is the radius different between the 2?

[Hinomaru]

Looks like there is only one correct rotor shield for the CB750, part no: 45140-341-670 and it fits the following models:

CB750A  (76) MOTORCYCLE, JPN, VIN# CB750A-7000001
CB750A  (77) MOTORCYCLE, JPN, VIN# CB750A-7100001
CB750A  (78) MOTORCYCLE, JPN, VIN# CB750A-7200001

CB750F  (75) MOTORCYCLE, JPN, VIN# CB750F-1000002
CB750F  (76) MOTORCYCLE, JPN, VIN# CB750F-2000003

CB750K2 (72) MOTORCYCLE, JPN, VIN# CB750-2000001
CB750K3 (73) MOTORCYCLE, JPN, VIN# CB750-2200001
CB750K4 (74) MOTORCYCLE, JPN, VIN# CB750-2300001
CB750K5 (75) MOTORCYCLE, JPN, VIN# CB750-2500001
CB750K6 (76) MOTORCYCLE, JPN, VIN# CB750-2540001
CB750K7 (77) MOTORCYCLE, JPN, VIN# CB750-2700009
CB750K8 (78) MOTORCYCLE, JPN, VIN# CB750-2800001

[CycleRanger]

Looks like there is only one correct rotor shield for the CB750, part no: 45140-341-670..

 Yes, if only Honda put the part number on the darn thing! 
 
 I was told the longer shield came from a 750, but based upon further research (i.e. Googling) it does appear it is for a 550, although it does fit on the 750.
Maybe someone can take a look at or a pix of a 550 shield and chime in.

Thx all!

[Skunk Stripe]

Could be that honda changed the design on the part but made sure it still fit all years. Wouldn't be the first time.