Wacker Neuson BTS 930-8340 Operating instructions

www.wackergroup.com
Cut-Off Saws
BTS 930-8340
BTS 935-8341
BTS 1030-8339
BTS 1035-7975
REPAIR MANUAL
0118754en 005
0903
0118754EN

BTS Repair Table of Contents
wc_br0118754enTOC.fm 1
1. Technical Data 5
1.1 BTS 930 / BTS 935 / BTS 1030 / BTS 1035 ........................................ 5
2. Special Tools 6
3. Clutch 7
3.1 Dismantling the clutch/drum ................................................................. 7
3.2 Mounting muffler and heat plate ........................................................... 8
3.3 Repairing the clutch .............................................................................. 8
3.4 Mounting the clutch/drum ..................................................................... 9
4. Ignition System 10
4.1 Checking the spark plug ..................................................................... 10
4.2 Replacing the plug connector ............................................................. 11
4.3 Removing/assembling the ignition / short circuit cable ....................... 12
4.4 Removing/checking/mounting the ignition armature .......................... 14
4.5 Removing/mounting the flywheel ....................................................... 15
5. Starting System 16
5.1 Removing/mounting the starter / return spring ................................... 16
5.2 Pretensioning/checking the return spring ........................................... 17
5.3 Replacing the starter ratchet .............................................................. 17
6. Carburetor 18
6.1 Setting the carburetor ......................................................................... 18
6.2 Removing the carburetor and intake hose ......................................... 19
6.3 Carburetor - dismantling/testing the control side ................................ 20
6.4 Carburetor - dismantling/testing the pump side .................................. 21
6.5 Carburetor - Cleaning the fuel filter .................................................... 21

Table of Contents BTS Repair
wc_br0118754enTOC.fm 2
7. Hood System / Air Filter / Winter Operation 22
7.1 Air Filter ...............................................................................................22
7.2 Winter Operation .................................................................................23
8. Front Handle / Vibration Absorbers 24
8.1 Removing and replacing the bracket handle .......................................24
8.2 Replacing the vibration absorbers .......................................................24
9. Fuel Tank / Fuel Filter 25
9.1 Removing/inserting the ventilation valve .............................................25
9.2 Replacing the throttle lever mechanism ..............................................25
9.3 Replacing the fuel pipe ........................................................................26
9.4 Testing the fuel filter ............................................................................26
10. Cylinder / Piston / Decompression Valve 27
10.1 Dismantling/mounting the cylinder / piston ..........................................27
10.2 Testing the decompression valve ........................................................28
11. Crankcase / Crankshaft 29
11.1 Crankcase / crankshaft ........................................................................29
12. Cutting Attachment 30
12.1 Replacing the pressure disc ................................................................30
12.2 Removing / mounting the V-belt pulley ................................................30
12.3 Replacing the drive axle ......................................................................31
12.4 Removing the complete pressure ring .................................................31
12.5 Cutter guard holding attachments .......................................................31
12.6 Replacing the guard stop ....................................................................32
12.7 Replacing the fixing screw ...................................................................32

BTS Repair Table of Contents
wc_br0118754enTOC.fm 3
12.8 Removing / mounting the cutting device bearings .............................. 33
12.9 Adjusting the cutter guard holding attachment ................................... 34
12.10 Tensioning the V-belt ......................................................................... 34
13. Torques 35
13.1 BTS 930 / BTS 935 / BTS 1030 / BTS 1035 ...................................... 35

Table of Contents BTS Repair
wc_br0118754enTOC.fm 4

BTS Repair Technical Data
wc_td000126gb.fm 5
1. Technical Data
1.1 BTS 930 / BTS 935 / BTS 1030 / BTS 1035
Item No. BTS 930
0008340 BTS 935 0008341 BTS 1030 0008339 BTS 1035 0007975
Saw
Displacement cm³ (in³) 62 73
Bore mm (in.) 47 (1.8) 50 (2.0)
Stroke mm (in.) 37 (1.5) 37 (1.5)
Max. Power kW (Hp) 3.3 (4.4) 4.2 (5.5)
Max. Torque Nm 4.0 5.0
Idling Speed rpm 2500 2500
Clutch engagement speed rpm 3800 3800
Engine speed limitation rpm 9350 9350
Max. spindle speed rpm 4300 4300
Carburetor (diaphragm) type Tillotson HS-273 A
Ignition system
(with speed limitation) type electronic
Spark plug type NGK BPMR 7A / BOSCH WSR 6F /
CHAMPION RCJ 6Y
Electrode gap mm (in.) 0.5 (0.020)
Fuel consumption1) l/h (qts./h) 1.85 (2) 2.36 (2.5)
Specific consumption1) g/kWh 500 500
Fuel tank capacity l (qts.) 1.1 (1.2) 1.1 (1.2)
Mixture ratio (fuel/two-stroke oil) 50:1 50:1
Cuttingdiscfor80m/sec. 2)
(DSA approved) mm 3) 300/20.0/5 350/24.5/5 300/20.0/5 350/24.5/5
Arbor diameter mm 20.0 25.4 20.0 25.4
V-belt AVX 838 LA AVX 838 LA
Overall weight 4) kg (lbs.) 9.7 (21) 9.9 (22) 9.8 (21) 10 (22)
1) At max. load per ISO 8893
2) Circumferance speed at max. engine speed
3) Outside diameter / arbor hole / thickness
4) tanks empty, without cutting disc.

Special Tools BTS Repair
wc_tx000326gb.fm 6
2. Special Tools
Ref. Part Number Description
1. 0068900 Puller for flywheel
2. 0117570 Puller for oil seals
3. 0117573 Puller for ball bearing counter support
4. 0117569 Puller for ball bearing inside puller
5. 0117575 Set of piston ring tenson belt
6. 0117571 Piston stop wedge
7. 0117574 Mounting tool for clutch hub
3
4
5
6
12
7wc_gr001381

BTS Repair Clutch
wc_tx000298gb.fm 7
3. Clutch
3.1 Dismantling the clutch/drum
See Graphic: wc_gr001384 and wc_gr001385
3.1.1 To dismantle the clutch and drum, remove the cutting device (1), strut
(2) and V-belt cover (3).
3.1.2 To remove the cutting device, loosen the fixing screws (4). Remove
screw (5) to the point where the end of the screw projects from the
cover (arrow).
3.1.3 The side strut is fixed with 3 screws (7) to the tank and the collector for
the right upper damper device.
3.1.4 The cover for the V-belt is fixed to the crankcase with 3 screws (8).
3.1.5 To remove the clutch and drum, the piston must beblocked. Todo this,
unscrew the 3 screws (9) fixing the muffler (10) and insert the piston
stop wedge (0117571) into the exhaust port of the cylinder (11).
3.1.6 Unscrew the clutch with the special tool (0117574) and a 19mm
wrench (a).
Note: left-handed thread.
7
4
2
1
3
5
wc_gr001384
9
11
a
8
10
wc_gr001385

Clutch BTS Repair
wc_tx000298gb.fm 8
3.2 Mounting muffler and heat plate
See Graphic: wc_gr001386
When mounting the muffler (10) ensure that the heat plate (12) is
installed correctly.
Note: The heat plate goes directly onto the cylinder, then the gasket
(13) and muffler.
3.3 Repairing the clutch
See Graphic: wc_gr001386
3.3.1 The tension springs of the clutch can be removed/ replaced with
pointed pliers (b). If spares are required, the 3 tension springs are only
available as individual parts.
3.3.2 The tension springs should only be replaced as a set if replacement is
required.
3.3.3 If the hub / flyweight is defective, the complete clutch must be
replaced.
wc_gr001386
b
1
1212
1
13
1
1
1010

BTS Repair Clutch
wc_tx000298gb.fm 9
3.4 Mounting the clutch/drum
See Graphic: wc_gr001387
3.4.1 Before installing the clutch drum, the needle bearing that is pressed in
must be greased. (Alvania #2)
3.4.2 When mounting the drum and the clutch, be careful to mount the
washers in the right order.
•(1) Ring (sits in the groove of the crankshaft)
•(2) End collar (with recess towards ring)
•(3) Guide washer
•(4) Clutch guide washer, before assembly.
Press into the support on the back of the clutch hub.
1
2
3
4
wc_gr001387
a

Ignition System BTS Repair
wc_tx000299gb.fm 10
4. Ignition System
4.1 Checking the spark plug
See Graphic: wc_gr001388
4.1.1 Remove filter hood.
4.1.2 Pull spark plug socket (1) off the spark plug and remove spark plug (2).
4.1.3 Connect spark plug (2) with plug socket and hold toground (3). Pull out
starter cable. If no spark is produced, repeat procedure with new spark
plug.
Note: Switch (4) must be in position “I”.
4.1.4 Combustion and motor performance will be improved ifthe spark plugs
function properly. Dirty or faulty spark plugs should therefore be
cleaned or replaced.
• The spark plug pictured (a) has serious oil carbon deposits.
Clean or replace spark plug.
• This spark plug (b) is showing signs of wear (burning off) on the
middle electrode. Spark plug must be replaced.
STOP
1
0,5 mm
2
1
4
3
2
wc_gr001388
b
a

BTS Repair Ignition System
wc_tx000299gb.fm 11
4.2 Replacing the plug connector
See Graphic: wc_gr001389
Hold the plug connector spring using pointed pliers and push the
rubber cap backwards over the ignition cable.
Note: Grease the ignition cable slightly beforehand.
a
wc_gr001389

Ignition System BTS Repair
wc_tx000299gb.fm 12
4.3 Removing/assembling the ignition / short circuit cable
See Graphic: wc_gr001390, wc_g001391, wc_gr001392 and wc_gr001393
Removing
4.3.1 Unscrew the starter device that is fixed with 4 screws (a).
4.3.2 Unscrew filter hood.
4.3.3 Remove ignition and short circuit cable from the guide (1) of the hood.
4.3.4 Remove hood - to do this, unscrew the 3 screws (2).
4.3.5 The screw (2a) also holds the grounding wire.
4.3.6 Unscrew ignition from the ignition armature.
4.3.7 Loosen short circuit cable from the socket connection (b).
4.3.8 Loosen the hose clamp (3) of the intake hose.
4.3.9 Pull the suction hose (4) off the cylinder.
4.3.10 Loosen the locking device of the intake elbow from the tank housing.
To do this, push both levers inwards (arrows) and lift the intake elbow
slightly.
4.3.11 Push throttle control rod towards the cylinder using pointed pliers,
pulling upwards out of the guide of the gas grip (c).
4.3.12 Remove intake elbow with carburetor and choke shaft from the tank
housing (d).
4.3.13 Pull short circuit cable (5) from its place in the choke shaft (6).
4.3.14 Loosen grounding wire (7) from the socket connection of the contact
spring.
wc_gr001390
a12
2a
34
bwc_gr001391

BTS Repair Ignition System
wc_tx000299gb.fm 13
Assembling
4.3.1 When mounting the short circuit cable, make sure that the connection
between the connector lug of the short circuit cable and the contact
spring is in order (a).
4.3.2 Twist ignition cable into the ignition armature.
Note: To preventmoistureleakingin,fillprotectivecap (4) with silicone
before replacing.
4.3.3 As a safety measure, lay the short circuit cable in the brackets
underneath the ignition cable during assembly (b).
785
6
cd
wc_gr001392
wc_gr001393
b
4
a

Ignition System BTS Repair
wc_tx000299gb.fm 14
4.4 Removing/checking/mounting the ignition armature
See Graphic: wc_gr001394
Removing
4.4.1 Unscrew starting device.
4.4.2 Remove the two screws (1) of the ignition armature. Clip off ignition
and short circuit cable.
Checking
4.4.1 In the event of a fault, first check the ignition ground connection.
To do this, loosen and then tighten the screws (1) a few times, then
check ignition once again.
Mounting
4.4.1 Connect ignition and short circuit cable.
4.4.2 Position with 0.012" – 0.016" (0.3 mm – 0.4 mm) (a) between ignition
device and magnet on the flywheel.
4.4.3 Press ignition device firmly whilst at the same time tightening the
screws evenly.
1a
bwc_gr001394

BTS Repair Ignition System
wc_tx000299gb.fm 15
4.5 Removing/mounting the flywheel
See Graphic: wc_gr001395
Removing
4.5.1 Block the piston using the piston stop wedge.
4.5.2 Unscrew bolt (2) and remove washer (3).
4.5.3 Remove flywheel with pulling device 0037576 (a).
CAUTION: To avoid damage to the crankshaft, always use the
protective cap included with the pulling device.
Mounting
4.5.1 Before mounting the flywheel, the cone seat and the crankshaft (4)
must be cleaned.
4.5.2 The flywheel is tightened with a torque of 23 ft.lbs. (30 Nm).
wc_gr001395
23
a4

Starting System BTS Repair
wc_tx000300gb.fm 16
5. Starting System
5.1 Removing/mounting the starter / return spring
See Graphic: wc_gr001396
Removing the starter
5.1.1 Remove air duct (1).
5.1.2 Relieve the tension on the return spring by pulling out the starter cable
(2) slightly.
5.1.3 Hold cable drum and remove cable from rope drum. Let drum spool
back slowly.
Removing the return spring
5.1.1 To remove the return spring, remove the circlip ring (3); the return
spring (4) is in a cartridge which is fixed to the fan housing with three
screws (5).
Note: Lightly grease new spring.
Mounting the return spring /starter cable
5.1.1 Thread cable through, knotting (6) into the cable drum and knotting (7)
into the starter grip (8).
5.1.2 The washer (9) is mounted between the starter grip and the knot.
Note: Melt cable ends.
3
6
8
9
7
4
2
1
wc_
g
r00139
6

BTS Repair Starting System
wc_tx000300gb.fm 17
5.2 Pretensioning/checking the return spring
See Graphic: wc_gr001367
Pretensioning the return spring
Wrap the starter cable as far as possible around the drum. Hold cable
tight and turn the drum with the cable 2-3 times to pretension (a).
Checking the return spring
When the starter cable is fully extended, the rope drum must still turn
at least half a turn (b).
5.3 Replacing the starter ratchet
See Graphic: wc_gr001367
5.3.1 Knock out the bolts with a punch (c).
5.3.2 To assemble, push the punch in so far that there is only 0.06"–0.07"
(0.15 mm–0.2 mm) between the ratchet and the bolt (10).
22
10
c
b
a
wc_gr001397

Carburetor BTS Repair
wc_tx000301gb.fm 18
6. Carburetor
6.1 Setting the carburetor
See Graphic: wc_gr001398
Set Idling Nozzle “L” at 1 3/8 (-1/16) turn
For the basic setting, turn in the idling nozzle “L” carefully as far as it
will go. Then back off “L” nozzle 1 3/8 turn.
For fine tuning, the “L” nozzle only needs to be changed by max.
- 1/16 of a turn.
“S” Idling Screw
When during idling the engine speed is too high (moving of cutting
disc) or too low (engine stalls), correct the the setting of idling screw
“S” (speed) accordingly.
“H” Main Nozzle
BTS 930/935: The main nozzle “H” is set at the factory to 6/8 of a turn.
BTS 1030/1035: The main nozzle “H” is set at the factory to 7/8 of a
turn except for machines built in 2002 (S/Ns 5289575 to 5355979)
which were set at the factory to 6/8 of a turn.
S
H
L
wc_gr001398