Oil filter difference?

[parkze]

Ok, my friend bought a 1998 Kat and everything ran great when he bought it, it has around 13k on it and doesn't appear to be beat on. He decided to change his oil and after completing the task his bike has picked up a tick or slight knock. I thought it was a valve and he kinda thinks it sounds like a timing chain slap. It does seem weird that the noise started after the oil change. The only thing that is different from when it was not knocking is the new oil and filter. The old filter was a Suzuki Filter made by Tokyo Roki 16510-34E00 and it has a small hole in the check valve inside the filter. The other is a Suzuki 16510-03G00-X07 does not have the hole. Heres his question:

What does that hole in the check valve do on the one tokyo roki filter? Does it help with low rpm oil pressure?

[IndyGunner]

if that was the first oil change id say you probably ruined the engine somewhere....but if not most likely the valves.... at 13,000 katanas are about due for a valve tune/carb sync which causes sounds like that.... check my youtube for a sound video