I think the "compact" part refers to the "outside" part of the plug, but the "low angle ground electrode" part is the bit that probably makes a difference.

The MC16 uses the ES (or ECS) plug; from MC18 onwards, Honda specifies BR9ECM.

If the ES or ECS works then it works, but I'd say stick with the specified plug as the more you change the spec' the more likely you are to encounter problems.
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Andy.
NSR-WORLD.COM

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