SERVICE MANUAL - JUKI

®
SEWING MACHINE
HZL-25Z
SERVICE MANUAL

[ 1 ] DISASSEMBLING OF OUTER PARTS
SECTION 1
PAGE 1
1. Base cover
1. Lower presser foot and lay machine.
2. Remove 3 screws (1) and take out base cover (2).
* Re-assembling should be done in the reverse way.
2. Gear cover
1. Remove screw (1) and take out gear cover (2).
* Re-assembling should be done in the reverse way.

3. Face cover
SECTION 1
PAGE 2
Disassembling
1. Raise presser foot lifter (1).
2. Remove screw (2) and take out face cover (3).
Re-assembling
1. Raise presser foot lifter (1).
2. Insert presser foot lifter (1) into small window (4) of face cover (3).
3. Insert jut (6) of face cover (3) into hole (5) of arm.
4. Fix screw (2) fitting face cover profile to arm profile.

4. SIDE COVER
SECTION 1
PAGE 3
Disassembling
1. Remove screw (1), (9).
2. Push cover (2) as indicated by arrow inserting your finger into the bobbin
winder hole (3) and take out cover (2). 〔Cover (2) has fitting hook (4).〕
3. When it cannot be removed by the above way, take out base cover (5) and
remove cover (2) from lower part.
Re-assembling
1. Insert hook (6) of cover (2) into small window (7) of base cover (5).
2. Set hook (4) of cover (2) into the inside of front cover (8) and fix by screw (1), (9).

5. FRONT COVER
Disassembling
1. Remove side cover and face cover. 〔See page 2 and 3. 〕
2. Remove screws (1), (2), (3) and then securing plate (4).
SECTION 1
PAGE 4
3. Take out face cover (8) removing hook (7) from small window (6) of base
cover (5).
Re-assembling
1. Insert hook (7) of front cover (8) into small window (6) of base cover (5).
2. Fix screws (1), (2) and (3) putting front cover (8) upon arm profile. Also fix
securing plate (4).

6. SHUTTLE COVER
Disassembling
1. Remove screw (1) and take out securing plate (2).
2. Remove shuttle cover (3) extracting as indicated by arrow.
SECTION 1
PAGE 5
* Re-assembling should be done in the reverse way.

7. Hand wheel
SECTION 1
PAGE 6
Re-assembling
1. Set washer (a) and washer (b) in position as illustrated and fix them by
tightening stud screw (c) by hand.
2. Set clutch wheel (d) in position so that its projected portion may be positioned
as illustrated.
3. Fix clutch wheel (d) with screw and tighten it clockwise.
** Disassembling should be done in reverse way.

[ 2 ] ADJUSTMENTS
* Adjustment can be made with or without removal of outer parts.
SECTION 2 - 0
PAGE 1
Adjustment
Without
removing
outer
parts
Front
cover
Removing outer parts
Face
cover
Side
cover
Gear
cover
Base
cover
2 - 1 L-R positioner ○
2 - 2
Needle position
Straight and Zigzag max
2 - 3 Needle side motion ○
○
2 - 4 Clearance cam and cam follower ○
2 - 5 Feed dog height ○
2 - 6 Feed dog longitudinal positioning ○
2 - 7 Feed dog lateral positioning ○
2 - 8
Feed dog timing
Vertical Movement
2 - 8
Feed dog timing
Lateral Movement
2 - 9 "0"-Feeding needle position ○
○
○
2 - 10 Buttonhole sewing -"0" feeding ○
2 - 11 Balance of reverse stitch length ○
2 - 12 Balance of stitch length - stretch stitch ○
2 - 13 Presser foot height ○
2 - 14 Needle height ○
2 - 15 Needle clearance to Shuttle ○ ○
2 - 16 Needle timing to Shuttle ○
2 - 17 Control panel pointer positioning ○
2 - 18 Belt tension ○
2 - 19
Hooking Fork Position of
Needle Threader
2 - 20 Bobbin winder ○
2 - 21 Rubber foot height ○
○

2 - 1 L - R positioner
SECTION 2 - 1
PAGE 1
Checking:
1. Move the needle to the left end by hand.
2. Check if the needle touches the left end of needle hole of needle plate.
NOTE: * Needle will be broken if needle is outside of left end of needle hole.
* Selector dial can not be turned smoothly if there is clearance of
more than 0.3 mm between left end of needle hole and needle.
Adjustment:
1. Lay the machine.
2. Loosen screw (1) and move L - R positioner (2) to left or right for adjustment.
3. Tighten screw (1).

SECTION 2 - 2
PAGE 1
2 - 2 Needle position - Straight stitching and Zigzag stitching,
maximum width
Checking:
1. Remove presser foot.
2. Set machine at "straight stitching A" by turning selector dial.
3. Turning hand wheel by hand, lower the needle and check if needle point
comes to the center of needle plate hole.
4. Set machine at "zigzag stitching C (maximum width)" by turning selector dial.
5. Turning hand wheel by hand, move needle to right and left end, and check if
each clearance between needle and needle hole end of needle plate is equal.
Straight stitching A
Zigzag stitching C
(maximum width)
Adjustment:
1. Remove face cover.
2. Loosen screw (1).
3. Turning eccentric pin (2), adjust needle position.
4. Tighten screw (1) after adjustment.

2 - 3 Needle Position at Zigzag Stitching
SECTION 2 - 3
PAGE 1
Checking:
1. Set machine at "zigzag stitching C, (maximum width)" by turning selector dial.
2. Bring needle to right hand lowest position. Slowly lift up needle and observe
its leftward movement when leaving upper surface of needle plate.
3. Needle should move to left in the range of 0.1 - 0.3 mm when needle point
comes about 1 mm above the needle plate surface.
4. Following ( × ) marked illustrations indicate wrong situation.
Too late
Too early
Adjustment:
1. Remove front cover.
2. Loosen one out of 2 screws (2) on worm gear (1). Another should be set
temporarily.
3. Holding hand wheel, turn worm gear (1), and adjust the angle of worm gear
against gear.
If side motion too early ð Turn worm gear (1) towards you.
If side motion too late ð Turn worm gear (1) away from you.
4. Tighten 2 screws (2) securely after adjustment.
Gear
NOTE: While adjustment, do not move worm gear along shaft. (Otherwise,
engagement with gear and needle side motion is seriously changed.)

2 - 4 Clearance between zigzag cam and cam follower
SECTION 2 - 4
PAGE 1
Checking:
1. Remove presser foot.
2. Set machine at "zigzag stitching C, (maximum width)" by turning selector dial.
3. Lower needle to left side and its lowest position.
4. Turn selector dial towards you (anti-clockwise) and set it between "zigzag
stitching (maximum width)" and "blind stitching".
5. Check if needle point moves about 0.35 mm from above "3" position to left.
Adjustment:
1. Remove side cover.
2. Turn screw (1).
Less than 0.35 mm ð Turn it clockwise.
More than 0.35 mm ð Turn it anti-clockwise.

2 - 5 Feed Dog Height
SECTION 2 - 5
PAGE 1
Checking:
1. Set stitch length control at "Maximum", and selector dial at "Straight Stitching A".
2. Remove needle and presser foot.
3. Set feed dog at highest position by turning hand wheel by hand.
4. Check to see if feed dog height (A) is 1.0 mm from needle plate.
Adjustment:
Adjust feed dog height by inserting the minus screw driver into feed lifting arm
(1) and moving it up or down.
Feed dog too low ð Turn the screw driver clockwise.
Feed dog too high ð Turn it anti-clockwise.

2 - 6 Feed dog Longitudinal positioning
SECTION 2 - 6
PAGE 1
Checking:
1. Set stitch length at maximum, and selector dial at "Straight Stitching A".
2. Turning hand wheel, move feed dog to the rear end position, and see if rear
edge of center front dog keeps clearance (A) to the needle plate hole.
3. Move feed dog to the front end, and see if front edge of center dog keeps
clearance (B) to the needle plate hole.
Adjustment:
1. Remove side cover.
2. Move feed dog to its extreme front end position.
3. Loosen screw (2). Moving feed dog forward or backward, adjust the angle
of arm (3) against feed shaft (4).
4. Tighten screw (2) securely after adjustment, keeping the angle of the arm
as adjusted.

2 - 7 Feed Dog Lateral positioning
SECTION 2 - 7
PAGE 1
Checking:
1. Set machine for "maximum stitch length".
2. Check if the groove of needle plate touches left end of feed dog.
3. Check if noise is not made.
4. Check if feed dog keeps alignment against groove of needle plate.
Adjustment:
1. Remove gear cover.
2. Adjustment for above (Checking 2 and 3)
• Loosen screw (2) of setting plate (1), and adjust by moving horizontal
shaft assy (3).
3. Adjustment for above (Checking 4).
• Loosen 2 screws (4). Feed dog (5) must touch groove (6) of needle plate
correctly.

2 - 8 Feed Dog Timing
SECTION 2 - 8
PAGE 1
Vertical Movement
* * Before checking, follow Section 2 - 5 Feed Dog Height.
Checking:
1. Set machine for maximum stitch length.
2. Turning hand wheel, move down feed dog.
3. Check if vertical clearance (P) between needle point and needle plate surface
is within the range of 4 - 6 mm when top of feed dog reaches needle
plate surface level.
Adjustment:
1. Remove base cover.
2. Loosen screw (2) of feed lifting cam (1).
3. Adjust feed dog timing to needle by slightly rotating feed lifting cam (1) in
either direction as shown.
To retard timing ð Turn the cam to A - direction.
To advance timing ð Turn the cam to B - direction.
4. Tighten screw (2) after adjustment.

SECTION 2 -8
PAGE 2
Lateral Movement
Checking:
1. Set machine for maximum stitch length.
2. Set feed dog at the start of its movement (when cam (1) starts to activate
forked connection).
3. Turning hand wheel, bring up needle bar to its highest dead point (A).
4. Check if total lateral movement (B) of feed dog during the period from Step
2 to Step 3 above is within the range of 0.1 - 0.3 mm.
Step 2 Step 3
Adjustment:
1. Remove face cover.
2. Loosen the screw (2) of feed rocking cam (1).
3. Holding feed rocking cam, turn hand wheel and adjust the angle of the cam
to upper shaft.
To retard timing ð Turn hand wheel towards you.
To advance timing ð Turn hand wheel away from you.
4. Tighten set screw (2) securely after adjustment.

2 - 9 "0" - Feeding Needle Positioning
SECTION 2 - 9
PAGE 1
Checking:
1 Set stitch length control at "0", and selector dial at "Straight Stitching A".
2. Place paper under presser foot and take 11 stitches without thread.
3. Deviation of all stitches must be within 0.6 mm in forward direction (about
2/3 of needle thickness).
Adjustment:
1. Inserting the plus screw driver through the hole and adjust the screw inside
of the machine.
Fig. a ) ð Turn anti-clockwise.
Fig. d ) ð Turn clockwise.

2 - 10 Buttonhole sewing - "0" feeding
SECTION 2 - 10
PAGE 1
Checking:
1. Set stitch length control "4".
2. Set machine at "BH No.1, 3" by turning selector dial. (Use buttonhole guide.)
3. Place the paper under buttonhole guide and take 11 zigzag stitches without
thread.
4. Deviation of all stitches must be within 0.6 mm in forward direction (about
2/3 of needle thickness).
Adjustment:
1. Remove side cover.
2. Insert the minus screw driver into the hole (1).
3. Adjust the stitch length within the range of 0 - 0.6 mm by turning driver anticlockwise
or clockwise.

2 - 11 Balance of reverse stitch length
SECTION 2 - 11
PAGE 1
Checking:
Reverse stitch length is within the range of 3.0 - 3.7 mm.
Adjustment:
1. Remove side cover.
2. Loosen screw (3).
3. Holding reverse lever (1), adjust the reverse lever arm (2) upward or
downward and tighten screw (3).
Reverse stitch length is short ð Tighten the screw (3) lifting (2) up.
Reverse stitch length is long ð Tighten the screw (3) lowering (2).
Upward
Downward

SECTION 2 - 12
PAGE 1
2 - 12 Balance of stitch length - Stretch stitching
NOTE: Before checking, follow Section 2 - 9 "0" - feeding needle position.
Checking:
1. Set machine for "zigzag stitching C".
2. Set for "stretch stitching ( )" by turning stitch length control.
3. Sew on a piece of paper and check needle holes on it.
4. Needle must pierce paper 3 times at the same point, on both right and left
end of zigzag stitches.
A
A
Stitch length control ( ) is normal position for stretch stitching.
If you select (L), stitch becomes A .
If you select (S), stitch becomes B .
Adjustment:
1. Remove side cover.
2. Turn lever (1) in either direction to correct the condition.
Turn the lever (1) up ð Reverse stitch length becomes longer.
Turn the lever (1) down ð Forward stitch length becomes longer.
Upward
Downward

2 - 13 Presser Foot Height
SECTION 2 - 13
PAGE 1
Checking:
1. Lower feed dog below the needle plate.
2. Lift up presser foot lever.
3. Check and see if clearance (A) between needle plate and presser foot is
about 5.5 mm.
Adjustment:
1. Remove face cover.
2. Loosen screw (2) of presser bar clamp (1) and adjust the height by vertically
sliding presser bar (3).
3. Tighten screw (2) securely after adjustment, keeping alignment of the foot
against feed dog.

2 - 14 Needle Height
SECTION 2 - 14
PAGE 1
Checking:
1. Remove presser foot.
2. Set selector dial at "Straight Stitch A".
3. Turning hand wheel, bring the needle bar to its highest position.
4. Check and see if the distance between needle point and needle plate surface
is about 14.6 mm.
Adjustment:
1. Remove face plate.
2. Loosen screw (2) of needle bar clamp (1).
3. Vertically sliding needle bar, correct the needle height.
4. Tighten screw (2) securely checking needle hole side after adjustment.
NOTE: After adjustment, follow "2 - 19 Replacement of needle hole threader lever".

2 - 15 Needle Clearance to Shuttle
SECTION 2 - 15
PAGE 1
Checking:
1. Remove bobbin case and shuttle race cover.
2. Set #14 needle.
3. Set machine at "Straight Stitch A" by turning selector dial.
4. Turning hand wheel, bring the shuttle point to the center line of needle.
5. Check if needle clearance to shuttle point (A) is 0 to 0.1 mm.
6. Needle must not touch needle hole.
Adjustment:
1. Remove face cover.
2. Remove screw (1), and loosen screw (2).
3. Move the shaft (3) of supporting assy.
To increase clearance ð Move shaft (3) away from you.
To decrease clearance ð Move shaft (3) towards you.
4. After adjustment, tighten screw (2) keeping shaft (3) from moving.
5. Tighten screw (1).
※ Check if needle does not touch needle hole after adjustment.
If needle touches needle hole, following adjustment is to be made.
Backward
Forward

Adjustment if needle touches needle hole:
SECTION 2 - 15
PAGE 2
1. Bring needle at center of needle hole following the method of "2 - 15
Needle Clearance to Shuttle (Adjustment)".
2. Remove gear cover.
3. Following adjustment is to be made depending on situation.
A - Needle touches front of needle hole (Fig. a ).
1 Loosen screws (4), (5).
2 Adjust needle clearance to shuttle by moving shuttle race assy (6)
away from you (A) and tighten screws (4), (5).
3 Loosen two screws (7). Adjust backlash between lower shaft gear
(8) and shuttle shaft gear (9) and tighten two screws (7).

SECTION 2 - 15
PAGE 3
B - Needle touches back of needle hole (Fig. b - PAGE 2).
1 Loosen screws (11), (12) of setting plate (10) for lower shaft bush.
However, lower shaft bush (13) must not float. (Big clearance should
not be made between setting plate and bush.)
2 Moving lower shaft gear assy (14) to left (C). Lower shaft gear (8)
must always engage with shuttle shaft gear.
3 Loosen screws (4), (5).
4 Adjust needle clearance to shuttle by moving shuttle race assy to
wards you (B direction - PAGE 2) and tighten screws (4), (5).
5 Move lower shaft gear assy (14) along shaft and adjust backlash be
tween lower shaft gear (8) and shuttle shaft gear (9).
6 Tighten screws (11), (12).
※ Check following "Checking rotating direction of shuttle race assy" (next
page) and "2 - 15 Needle timing to shuttle" after adjustment.

Checking rotating direction of shuttle race assy:
Align needle with the right edge (B) of cut portion (A).
SECTION 2 - 15
PAGE 4
Checking backlash of shuttle shaft gear and lower shaft gear:
1. Remove bobbin case, shuttle cover, and shuttle hook.
2. Turning hand wheel, rotate shuttle driver (1) and locate the point of minimum
backlash.
3. Check if the backlash is approximately zero at this point.

2 - 16 Needle Clearance to Shuttle
SECTION 2 - 16
PAGE 1
* * Before checking, follow Section 2 - 2 Needle Position at Straight and Maximum
Zigzag Width and 2 - 14 Needle Height.
Checking:
1. Remove bobbin case and shuttle race cover.
2. Set machine at "zigzag stitching C, (maximum width)" by turning selector dial.
3. Turning hand wheel, bring up needle from its right hand lowest point until
shuttle hook point comes to align with left side of needle. Check if clearance
(A) between hook point and upper edge of needle eye is about 1.0 mm.
Adjustment:
1. Loosen bolt (2) of lower shaft arm (1).
2. Rotate shuttle with finger until hook point comes to align with the left side of
needle.
3. Holding shuttle at this position, slowly bring up needle until the correct vertical
clearance is attained between shuttle hook point and upper edge of
needle eye.
4. Tighten screw (2) securely after adjustment, keeping the angle of the shuttle
as adjusted.
5. Recheck needle/ shuttle timing after adjustment.

2 - 17 Control panel pointer positioning
SECTION 2 - 17
PAGE 1
Checking:
1. Set machine for "BH left 2" (pointer at highest position).
2. Check if pointer is set in correct position of window of control panel.
Adjustment:
1. Remove side cover.
2. Loosen two screws (1) of selector dial and set pointer turning dial.
3. Tighten two screws (1).
Control panel
Selector dial
Gear
※ Above adjustment can not be made if belt tension is too loose.
Then loosen screw (2) and adjust belt tension turning eccentric roller (3).

2 - 18 Belt tension
SECTION 2 - 18
PAGE 1
* Belt tension should be adjusted in case of belt jumping on heavy material sewing
or slow rotation.
Reference:
Belt is bent about 7 mm when pushing middle portion of belt between upper
shaft and motor with pressure of 200 g.
Pressure
Adjustment:
1. Remove side cover.
2. Loosen two screws (1). Adjust belt tension by moving motor and tighten
screws (1).

2 - 19 Hooking Fork Position of Needle Threader
Checking:
1. Check and see if #14 needle is used and it is not bent.
2. Set machine for Straight Stitch at center needle
position.
3. Raise the needle to its highest position by rotating
the hand wheel towards you.
4. Lowering needle hole threader lever, check and
see if hook (1) inserts into needle hole.
( 3 )
SECTION 2 - 19
PAGE 1
( 1 )
Adjustment when hook (1) is deviated horizontally or bent vertically:
Correct the condition using small screw driver as illustrated.
Deviated horizontally
Bent vertically
Adjustment when hook (1) is deviated vertically:
1. Remove face cover.
2. Turning hand wheel by hand, bring needle bar to its highest
position.
3. Lower needle hole threader lever (3).
4. Pushing needle hole threader lever (3) away from you,
insert hook (1) into needle hole, and keep it.
5. Loosen stopper screw (4).
6. Holding threader stopper (4) onto stopper pin (8), tighten stopper screw (5).
Make sure to align the screw (5) with the screw (7) on needle bar clamp (6)
Center
( 8 )
( 4 )
( 5 )
( 6 )
( 7 )

SECTION 2 - 19
PAGE 2
Exchange of needle hole threader lever:
1. Remove presser foot.
2. Raise needle to its highest position.
3. Push needle hole threader lever down by pliers or forked driver as illustrated.
4. Remove needle hole threader lever (3).
Knock pin
( 3 )

2 - 20 Bobbin Winder
SECTION 2 - 20
PAGE 1
A. Winding balance
Checking:
1. Wind thread on the bobbin.
2. Check if the thread is wound evenly.
Adjustment:
1. Insert box driver (hexagonal box driver, etc.) into the bobbin winder shaft
and bent it.
Lower part is wound too much (c) ð Bent to left side.
Upper part is wound too much (a) ð Bent to right side.
Left
Right
B. Winding volume
Adjustment:
1. Loosen screw (1) and adjust the bobbin winder stopper (2) ( ).
(The best volume of winding is 80% at maximum.)

2 - 21 Rubber foot height
SECTION 2 - 21
PAGE 1
Checking:
1. Put the machine on the flat table.
2. Check the balance of the machine.
Adjustment:
1. Loosen nut (1).
2. Insert the driver into the hole (2) and adjust by turning it.
3. Tighten nut (1) securely after adjustment.
* Use screw driver P#.74793 included in the accessories.

®
8-2-1, KOKURYO-CHO,
CHOFU-SHI, TOKYO 182-8655, JAPAN
PHONE: 03(3480)5034
FAX: 03(3480)5037
http: //www.juki.co.jp
E-mail: hsm@juki.co.jp
Copyright © 2007 JUKI CORPORATlON
All right reserved throughout the world.
40058010 2007/01