They're probably the same as the small Super Tigre needles, which have a thread of M2.3 X 0.4. You could fit a completed US C/L Stunt ST small NVA as used on the Fox 35. Otherwise try the usual Ukrainian sources. See below. The bloke posts on Facebook and seems to be reliable. He'll know about the MVVS threads and may be able to make you spares. Won't be cheap either way. You could try to substitute a complete Enya small NVA from Bobbie Brooks.