If you can't find any secondhand ones.
Try Allens Performance (01949-836733) they stock all the Mikuni main jets & pilot jets - got all of mine from there
Dave,
I might have 4 in me garage,I changed mine to dynojets,last time the bike was on the Dyno.
Let me have a look & I will drop ya a mail,I cant remember what was in, but pretty sure they were 120
Are Dynojet mains compatable with standard Mikuni mains ie are the stamped sizes the same measurement .
I have a few sizes of Dynojet main jets but they are slightly smaller physically than slotted Mikunis .