JUKI MF-7900 Series Engineer's Manual page 43

Adjustment procedures
Remove setscrews ❷ and remove needle cooler unit ❸ and
1.
cam cover ❾ .
Adjust the height of rear needle guard ❶ with setscrew ❺ and
2.
adjust the longitudinal position with setscrew ❼ .
❹
(Caution) After the adjustment, check by manual turning wheth-
er the top end of looper ❹ does not come in contact
with the needle.
When turning the rear needle guard cam ❻ in the direction of
3.
rotation, the timing of rear needle guard ❶ is advanced, and
when turning it in the reverse direction, the timing is retarded.
❺
❼
– 29 –
Results of Improper adjustment
◦ When the clearance provided
between rear needle guard ❶
and the needle is large, stitch
skipping, blunt blade point of the
looper, or needle breakage will
be caused.
◦ When the contact of rear nee-
dle guard ❶ with the needle is
strong, blunt needle tip will be
caused.