Needle Jets Sizes, Mikuni, as determined by Factory Pro Tuning in 1981

M-0 2.500
N-0 2.550
O-0 2.600
P-0 2.650
Q-0 2.700
R-0 2.750
S-0 2.800
T-0 2.850
U-0 2.900
V-0 2.950
W-0 3.000
X-0 3.050
Y-0 3.100
Z-0 3.150


This is information that Factory Pro has had since about 1981.

These are the extrapolated blueprinted "spec sizes", based on information about 2 "blueprinted" needle jet sizes leaked years ago, by a friend.

Most of the original delivered needle jets are very slightly undersized. But, we would make the jet kits for the "as delivered" needle jets (not richer blueprinted ones).

All reamers, regardless of cost - (as in expensive is better than cheap, but not perfect enough) need to be relabled to their actual cutting size - Do not assume that a reamer cuts to the size that the manufacturer states.

.0002" is the accuracy that you need to be able to identify when doing precision tuning.