Assuming this is for the NC30, through a similar experience I found out the following....
Honda used a fairly generic 5/8 MC on many of the bikes in the 80's 90'sincluding the NC30. At some point in the 1990s they (for some reason) switched to a metric 14mm MC, so you need to check you get the right kit for your MC as 5/8"= 15.8750mm - hence not interchangeable.
As you can see the correct size/spec o f the MC is stamped on it (same on the rear MC)
wether it is 5/8" or 14mm.

I got a MC refurb kit which turned out to be 5/8" from GF. Thankfully he told me abou this issue so I checked when I got home and sure enough both my bikes are 14mm...which meant a re-order for a 14mm set ... OEM parts only unfortunately
