I am thinking of doing the tappets on my NC30 myself. I'm happy with the mechanics but can any one tell me how I need to go about ordering replacement shims? Do I order in a metric measurement 0.15 or are they sized 1, 1.5, 2, 2.5 etc. Or do I order a set? I will be getting the spares from D Silver. I know I will need to make a chart and some shims may fit somewhere else.

You order them by the size printed on them, eg 205 or 190. I wouldn't bother ordering a set unless you plan doing a lot of bikes, just not worth it as a kit (non Honda is ~85quid, Honda are ~3quid each).

You won't know what sizes you need until you open up the engine and check what you have and how far they are out, you may be all spot on, or you be able to swap round and only may need one.

Druid

I take it that it's the shims that wear then and I simply need to order the same size shim as a replacement for the worn ones?

No, the shims don't wear[1] the cams and seats and do.

What you'll have though is a difference between what is fitted and what you need, so say you should be 0.12 mm but it's actually 0.13 and you have a 200 shim fitted you'd fit a 0.01mm thicker shim so a 210

Druid

[1] Well they do but not enough to worry about in reality.

That's great thanks for the info. I'll give it a go and save myself a coule of hundres quid.