I can see that. Not only from the filter media but there is a rubber check valve behind those small holes that the oil flows through.
I tried to compare my Bosch filter to another brand filter I had lying around by pushing on it with a small screwdriver. It's hard to tell but I can see that if that rubber valve was too stiff it could impede oil flow.
I think I'll bite the bullet and buy another Honda filter and compare.
I changed my oil today and used a new Honda OEM filter.
After comparing it to the Bosch and the Purolator Pure One I found this out. There is virtually no difference between the Purolator and the Bosch except for the body color and the outside seal color.
The inside flow back rubber is the same silicone rubber material which is resistant to being pushed open with a screwdriver. It looks like it will do its job very well. Maybe too well for our low pressure systems.
I did not inspect the filter media.
With the Honda filter, the flow back preventer is made of a type of nylon material, I think, and it can be pushed open with a screw driver quite easily.
I think this is important.
A filter made for a car can have a more resistant flow back preventer due to the higher oil pressure present
in the cars motor.
The CB's oil pressure is only 13 psi at 1200 RPM. Any resistance to the oil flow will impact the amount of oil circulating in the engine I believe.
I have used Purolator filters in other bikes I have owned with no problems but that is going to stop.
I suggest you compare them for yourselves if there is any doubt.
I'm going to see if I can buy a bunch of the Honda filters online at a discount.