What are the standard jet sizes for an NC23 K?
What jets should the same bike have when restricted?
What jets should the same bike have when restricted AND fitted with a straight-through can, or is this a case of trial and error?

Fancy cleaning and balancing the carbs soon so may as well get the jets right.
Cheers,
Wozza

Just looked in the haynes manual.
for normal exhaust, unrestricted.

for K model.
Main jet = 105
Pilot Jet = 35

Cheers - am I right in thinking that restrictor washers will warrant smaller jets, whereas a straight-through can will warrant larger jets, and therefore standard jets shouldn't be far off? Sounds too simple to be correct!

I have a stainless race exhaust and straight through Micron can and the main jets are 114 and 112. This was recommended by Simon, the Dyno operator at MHP exhaust in Byfleet Surrey, who raced an NC23. The 112 jets were for the carbs with the short trumpets (for Hi rpm) and the 114s for the longer trumpets tuned for mid range rpm. Mine was making 59.1 bhp with 114s in all carbs. I haven't re-run it on the dyno to verify this set up, but it does run nice and strong at full throttle. Mine is a K model.
If you can afford a dyno session, it's well worth it because then you know the carbs will be set to your bikes specific engine and exhaust, and you can get verification of the 33 bhp with your washers fitted and correct fuelling.