I was about to ask this same question.

Mine was leaking in a major way. Was loosing complete reseviours full of fluid. I've taken it apart now and there are marks on the bore. Just not sure if these are scores deep enough to render it useless. Is there any definite way to tell?

Also. My car is an imported cb3 and has an h22a swap done before I bought it. So I'm not totally sure what BMC I have and what part to ask for. Says it's a Nissin part and has 15/16 on it. Does this give any clues? The local honda parts dept hates my car so I doubt they'll be very helpful.

thanks