Andy wrote:Hello dynamite, and welcome to the forum.
I don't have any data for the MC11 I'm afraid, but my (non)educated guess would be that I expect the B8ES plug (or more likely a B9ES probably) would be the correct one, and should be the same in both cylinders under 99% of cases.
Possibly the same plug required as the NS400R: BR8ES or BR9ES (gap 0.7~0.8mm).
Nice info sir, but I'm agree with you, no matter what is the engine type, I think the plug must be same, because the orginally from the fabric is like that.