Jconcepts BJ4 User manual

ITEMS NEEDED TO COMPLETE YOUR CAR:
1. R/C TWO CHANNEL SURFACE
FREQUENCY RADIO SYSTEM
2. BATTERY PACK (6 CELL SADDLE PACK)
3. BATTERY CHARGER (PEAK DETECTION)
4. ELECTRONIC SPEED CONTROL
5. R/C ELECTRIC MOTOR
6. PINON GEAR (SIZE TO BE DETERMINED
BY MOTOR CHOICE)
7. 1/10TH SCALE 4WD FRONT TIRES
(BOX ART SHOWN: BLOCKHEAD)
8. 1/10TH SCALE BUGGY REAR TIRES
(BOX ART SHOWN: X-2000)
4. HELPFUL TOOLS (NOT REQUIRED)
A. VERNIER CALIPERS
B. HOBBY SCISSORS
C. 2.5mm BALL END HEX DRIVER
3. MISC. TOOLS
A. NEEDLE NOSE PLIERS
B. THREAD LOCKING COMPOUND (BLUE)
C. HOBBY KNIFE (DANGER!) THIS KNIFE CUTS
PLASTIC AND FINGERS WITH EQUAL EASE
D. PRECISION RULER
E. FLAT FILE
2. NUT DRIVERS
A. 3/16"
B. 1/4"
C. 11/32"
1. ALLEN WRENCHES
A. .050"
B. 1/16"
C. 5/64"
D. 3/32"
E. 2.5mm
TOOLS NEEDED TO BUILD THIS KIT
CHASSIS PREPARATION:
CHASSIS
x 1 TOP DECK x 1
(2 PIECES)
STEERING RACK
x 1 BATTERY TRAY x 2
BATTERY STRAP
x 2
BEARING BLOCK
x 2
FRONT SHOCK
TOWER x 1
REAR SHOCK
TOWER x 1
CHASSIS COMPONENTS
FILE
NOTE CHASSIS
ORIENTATION
NOTE: THIS IS A CLEARANCE FOR THE BOTTOM OF THE REAR
TRANSMISSION CASE. A PROPERLY FILED CHASSIS WILL ALLOW
THE REAR TRANSMISSION CASE TO SIT FLAT ON THE CHASSIS.
FILE CAREFULLY! USE THE PROPER CASE TO CHECK THE FIT
WHILE REMOVING A SMALL AMOUNT OF MATERIAL AT A TIME.
1. FILE REAR TRANSMISSION SLOT WITH
THE BOTTOM SURFACE OF THE FILE.
FILE AT THE GREATEST ANGLE POSSIBLE
WITHOUT THE TOP SURFACE OF THE FILE
HITTING THE OTHER SIDE OF THE SLOT.
SEE FIGURE 1.
2. REFER TO FIGURE 2 FOR COMPLETED COMPARISON.
FIGURE 1
FIGURE 2
TOOLS
BAG A
STEP 1
PAGE 1

ASSEMBLING CHASSIS COMPONENTS:
1. ATTACH FRONT BULKHEAD TO CHASSIS WITH TWO 5-40 x 5/16" FLAT HEAD SCREWS.
2. ATTACH BEARING BLOCK WITH TWO 4-40 x 3/8" FLAT HEAD SCREWS. SECURE WITH TWO 4-40 LOCKNUTS.
3. ATTACH CENTER MOTOR MOUNT TO CHASSIS WITH THREE 4-40 x 5/16" FLAT HEAD SCREWS.
4. ATTACH CENTER BULKHEAD TO CHASSIS WITH TWO 4-40 x 5/16" FLAT HEAD SCREWS.
5. ATTACH REAR SUSPENSION MOUNT (FRONT) WITH TWO 4-40 x 5/16" FLAT HEAD SCREWS. NOTE DIRECTION
6. ATTACH REAR SUSPENSION MOUNT (BACK) WITH TWO 4-40 x 5/16" FLAT HEAD SCREWS. NOTE DIRECTION
APPLY BLUE THREAD LOCKING
COMPOUND WHERE NOTED.
(JUST A SMALL AMOUNT)
FRONT BULKHEAD
5-40 x 5/16" x 2
(APPLY A SMALL AMOUNT OF
THREAD LOCKING COMPOUND)
BEARING BLOCK
4-40 x 3/8" x 2
BEARING BLOCK AND
CHASSIS FROM BAG "A"
4-40 MINI
LOCKNUTS
x 2
CENTER MOTOR MOUNT
4-40 x 5/16" x 3 CENTER BULKHEAD
4-40 x 5/16" x 2
REAR SUSPENSION MOUNT
4-40 x 5/16" x 4
(APPLY A SMALL AMOUNT OF
THREAD LOCKING COMPOUND) (APPLY A SMALL AMOUNT OF
THREAD LOCKING COMPOUND)
(APPLY A SMALL AMOUNT OF
THREAD LOCKING COMPOUND)
FLAT EDGE OF FRONT MOUNT
SHOULD FACE FORWARD
REAR SUSPENSION MOUNT (FRONT) x 1
NOTE MOUNTING DIRECTION IN
ASSEMBLY BELOW
REAR SUSPENSION MOUNT (BACK) x 1
NOTE MOUNTING DIRECTION IN
ASSEMBLY BELOW
CENTER MOTOR
MOUNT x 1 CENTER BULKHEAD
x 1 CENTER BULKHEAD
CAP x 1
FRONT BULKHEAD
x 1 BATTERY POST
x 4
4-40 x 5/16"
FLAT HEAD
x 9
5-40 x 5/16"
FLAT HEAD
x 2
CHASSIS COMPONENTS
4-40 x 5/16"
SOCKET HEAD
x 8
4-40 MINI
LOCKNUT
x 2
4-40 x 3/8"
FLAT HEAD
x 6
#4 WASHER,
ALUMINUM
x 4
PAGE 2
BAG B
STEP 1

DIFF BOLT
THRUST WASHER
FEMALE SLIPPER
OUTDRIVE
SLIPPER PLATE
ALIGN HEXES
1. STACK THE FOLLOWING PARTS ONTO THE PARTIAL
ASSEMBLY IN THIS ORDER:
A. SLIPPER PAD
B. 78 TOOTH SPUR GEAR (ALIGN WITH SLIPPER PAD)
C. SLIPPER PAD (ALIGN WITH SPUR GEAR)
D. SLIPPER PLATE
E. MALE SLIPPER OUTDRIVE (ALIGN WITH SLIPPER PLATE)
2. CAREFULLY ALIGN ALL THE HEX SHAPED PARTS WHILE THE
SLIPPER PADS REST IN THE SPUR GEAR.
3. INSERT THE SLIPPER SPRING INTO THE MALE SLIPPER OUTDRIVE.
4. INSERT THE T-NUT INTO THE MALE SLIPPER OUTDRIVE UNTIL IT
TOUCHES THE DIFF SPRING. (APPLY A SMALL AMOUNT OF
THREAD LOCKING COMPOUND WHERE SHOWN)
5. TIGHTEN THE SLIPPER USING THE 5/64" ALLEN WRENCH,
BUT NOT COMPLETELY. JUST TIGHT ENOUGH TO HOLD
THE COMPONENTS IN PLACE.
SLIPPER ADJUSTMENT:
1. HOLD THE DIFF BOLT WITH A 5/64" ALLEN WRENCH.
2. SLIDE ONE THRUST WASHER ONTO THE DIFF BOLT.
3. SLIDE THE DIFF BOLT WITH THRUST WASHER INTO
THE FEMALE SLIPPER OUTDRIVE.
4. WHILE ALIGNING THE HEXES ON EACH PART, SLIDE
THE SLIPPER PLATE ONTO THE FEMALE SLIPPER OUTDRIVE.
5. HOLD THE PARTIAL ASSEMBLY WITH THE 5/64" ALLEN
WRENCH SO THAT THE SLIPPER PLATE IS FACING UP.
SLIPPER ASSEMBLY:
PARTIAL ASSEMBLY
SLIPPER PAD
SPUR GEAR
SLIPPER PAD
SLIPPER PLATE
MALE SLIPPER
OUTDRIVE
ALIGN HEX
WITH FEMALE
OUTDRIVE HEX
ALIGN HEXES
SLIPPER SPRING
T-NUT
APPLY A SMALL AMOUNT OF THREAD LOCKING
COMPOUND TO THE THREADED, ALUMIUM PORTION
SLIPPER OUTDRIVE
MALE x 1
78 TOOTH SPUR GEAR
x 1 OUTDRIVE SHIM
x 2
SLIPPER PAD
x 2 SLIPPER PLATE
x 2 3/8 X 5/8 BEARING
x 2
SLIPPER OUTDRIVE
FEMALE x 1
CENTER SLIPPER PARTS
DIFF T-NUT
x 1
SLIPPER SPRING
x 1
DIFF THRUST WASHER
x 1
DIFF BOLT
x 1
PAGE 3
BAG B
STEP 1
STEP 2

#4 WASHER
x 4
BATTERY POST
x 4
BATTERY TRAY
FROM BAG "A"
4-40 x 3/8"
FLAT HEAD
x 4
1. SLIDE ONE OUTDRIVE SHIM AND ONE 3/8" x 5/8" BEARING ONTO EACH SIDE OF THE SLIPPER ASSEMBLY.
2. SLIDE THE COMPLETE SLIPPER ASSEMBLY DOWN INTO THE CHANNELS OF THE CENTER BULKHEADS.
3. ATTACH THE CENTER BULKHEAD CAP WITH FOUR 4-40 x 3/8" SOCKET HEAD SCREWS.
4. ALIGN EACH BATTERY TRAY WITH THE SLOTS IN THE CHASSIS, AND SNAP INTO PLACE.
5. ATTACH EACH BATTERY POST WITH A 4-40 x 3/8" FLAT HEAD SCREW. MAKE SURE TO ALIGN THE HEX
ON EACH BATTERY POST WITH THE CORRESPONDING HEX IN THE BATTERY TRAY.
6. SLIDE THE BATTERY STRAPS ONTO THE BATTERY POSTS AS SHOWN BELOW.
7. ATTACH EACH BATTERY STRAP WITH TWO 4-40 x 5/16"
SOCKET HEAD SCREWS AND TWO #4 WASHERS.
ASSEMBLING CHASSIS COMPONENTS:
4-40 x 5/16"
SOCKET HEAD
x 4
1. THE SLIPPER IS ONE OF THE MOST CRITICAL ADJUSTMENTS ON THE BJ4. REMEMBER,
THE SLIPPER IS DESIGNED TO ABSORB IMPACTS FROM THE DRIVETRAIN. SETTING THE
SLIPPER TOO TIGHT WILL ONLY CAUSE PREMATURE DAMAGE TO THE DRIVETRAIN.
IN ADDITION, HAVING THE SLIPPER TOO LOOSE WILL NOT HELP CREATE TRACTION.
2. SCREW IN THE DIFF BOLT UNTIL THE SPRING IS FULLY COMNPRESSED. PAY CLOSE
ATTENTION TO THE ALIGNMENT OF THE PARTS. DO NOT OVERTIGHTEN THE BOLT.
WHEN YOU FEEL THE SPRING COMPRESSED, LOOSEN THE DIFF BOLT ONE TURN.
3. AFTER YOU HAVE DRIVEN THE CAR FOR ONE BATTERY PACK, CHECK THE SLIPPER
ADJUSTMENT. IF NECESSARY, REPEAT STEP 2 ABOVE.
4. IF MORE SLIP IS DESIRED, LOOSEN THE DIFF BOLT 1-1/4 TURNS FROM BOTTOM.
IF LESS SLIP IS DESIRED, LOOSEN THE DIFF BOLT 3/4 TURNS FROM BOTTOM.
SLIPPER ADJUSTMENT:
CENTER BULKHEAD CAP
4-40 x 3/8" x 4
OUTDRIVE SHIM
x 2
3/8" x 5/8" BEARING
x 2
(APPLY A SMALL AMOUNT OF
THREAD LOCKING COMPOUND)
COMPARE ASSEMBLY:
PAGE 4
STEP 3
STEP 4

DIFF THRUST WASHER
x 2
DIFF SPRING
x 1
SHORT OUTDRIVE HUB
x 1 LONG OUTDRIVE HUB
x 1
DIFF BOLT
x 1
3/16 X 5/16
DIFF BEARING
x 2
DIFF T-NUT
x 1
5/64 THRUST BALL
x 6
3/32 DIFF BALL
x 12
DIFFERENTIAL RING GEAR
x 1 DRIVE RING
x 2
DRIVETRAIN COMPONETS (DIFF x 2)
THRUST BALL ASSEMBLY:
1. HOLD THE DIFF BOLT WITH THE 5/64" ALLEN WRENCH
AND SLIDE ONE THRUST WASHER ONTO THE DIFF BOLT.
2. APPLY A GENEROUS AMOUNT OF BLACK GREASE TO THE
WASHER ON THE SIDE FACING AWAY FROM THE BOLT HEAD.
3. PLACE SIX THRUST BALLS INTO THE GREASE AGAINST THE BOLT
AND WASHER. ADD THE OTHER THRUST WASHER. THE GREASE
WILL HOLD THE BALLS IN PLACE DURING ASSEMBLY,
SANDWICHED BETWEEN THE WASHERS.
APPLY GENEROUS AMOUNT OF BLACK GREASE
HOLD WITH 5/64" ALLEN
WRENCH
DIFF BOLT
THRUST WASHERS
5/64
THRUST
BALLS
x 6
SHORT HUB ASSEMBLY:
1. INSERT THE THRUST ASSEMBLY INTO THE SHORT OUTDRIVE HUB.
2. ADD A LIGHT COAT OF STEALTH LUBE TO THE SHORT HUB FACE
WHERE SHOWN.
3. PLACE A DIFF DRIVE RING ONTO THE FACE OF THE SHORT HUB.
4. SLIDE A DIFF BEARING ONTO THE PROTRUSION OF THE SHORT HUB.
SMEAR A SMALL AMOUNT OF STEALTH LUBE
HERE TO HOLD THE DIFF DRIVE RING IN PLACE
THRUST ASSEMBLY
SHORT OUTDRIVE HUB
3/16 x 5/16 DIFF BEARING
DIFF DRIVE RING
NOTE: REMOVE ANY OIL RESIDUE FROM OUTDRIVE
HUB THOROUGHLY BEFORE APPLYING STEALTH LUBE
OUTDRIVE SHIM
x 1
BAG C
STEP 1
STEP 2
PAGE 5

1. TRIM ANY BURRS FROM THE INSIDE OF THE GEAR WITH A HOBBY KNIFE.
2. ADD A GENEROUS AMOUNT OF STEATLH DIFF LUBE TO THE RING GEAR
BALL HOLES AND PUSH IN THE TWELVE 3/32 DIFF BALLS. THEN PUSH IN
THE LUBE THAT CAME OUT.
TRIM ANY BURRS FROM THE INSIDE
OF THE GEAR WITH A HOBBY KNIFE
STEALTH DIFF LUBE
AFTER APPLYING THE STEALTH DIFF LUBE,
SNAP THE 3/32 DIFF BALLS IN PLACE
SHORT HUB ASSEMBLY
LONG HUB ASSEMBLY:
1. INSERT THE DIFF SPRING INTO THE LONG OUTDRIVE HUB.
2. INSERT THE T-NUT INTO THE LONG HUB UNTIL IT TOUCHES
THE DIFF SPRING.
3. ADD A LIGHT COAT OF STEALTH LUBE TO THE LONG HUB FACE.
4. PLACE A DIFF DRIVE RING ONTO THE FACE OF THE LONG HUB.
5. INSERT THE 3/16 x 5/16 DIFF BEARING INTO THE LONG HUB. NOTE: REMOVE ANY OIL RESIDUE FROM OUTDRIVE
HUB THOROUGHLY BEFORE APPLYING STEALTH LUBE.
3/16 x 5/16 DIFF BEARING
DIFF DRIVE RING
LONG OUTDRIVE HUB
DIFF SPRING
T-NUT
DIFF ASSEMBLY:
1. INSERT THE LONG HUB ASSEMBLY INTO THE SHORT HUB ASSEMBLY,
MAKING SURE YOU LINE UP THE BOLT IN THE HUB AND THE BOLT
THREADS INTO THE T-NUT.
CHECK ALIGNMENT OF THE HUBS
2. TIGHTEN THE DIFF WITH YOUR 5/64" ALLEN WRENCH, BUT NOT COMPLETELY.
3. SCREW IN THE DIFF BOLT A FEW TURNS THEN STOP TO ROTATE THE DIFF HUBS
IN OPPOSITE DIRECTIONS. THEN SCREW IN THE BOLT SOME MORE. FOLLOW
THIS PROCEDURE TO CHECK PROPER ALIGNMENT OF THE PARTS. THE
FOLLOWING NOTE CLARIFIES THIS.
READ THE FOLLOWING CAREFULLY
AS YOU TIGHTEN THE DIFF BOLT, PAY CLOSE ATTENTION TO THE FEELING WHEN THE SPRING IS FULLY
COMPRESSED. DO NOT OVERTIGHTEN THE BOLT. WHEN YOU FEEL THE SPRING COMPRESSED,
LOOSEN THE DIFF BOLT 1/4 TURN. NO MORE, NO LESS. AFTER YOU HAVE DRIVEN THE CAR FOR ONE
BATTERY PACK, RECHECK THE DIFF ADJUSTMENT AS ABOVE SO THAT WHEN YOU FEEL THE SPRING
FULLY COMPRESSED, LOOSEN THE DIFF BOLT 1/4 TURN. NEVER ADJUST THE DIFF ANY OTHER WAY.
NOW ASSEMBLE THE SECOND DIFF THE SAME WAY
TIGHTEN USING 5/64" ALLEN WRENCH
DIFFERENTIAL RING GEAR:
STEP 3
STEP 4
STEP 5
PAGE 6

3/8 x 5/8 BEARING
OUTDRIVE SHIMS,
VERY IMPORTANT
FINAL DIFF ASSEMBLY:
3/8 x 5/8 BEARING
x 4
1. SLIDE ONE OUTDRIVE SHIM AND ONE
3/8 x 5/8 BEARING ONTO EACH SIDE
OF THE DIFF ASSEMBLY.
SCALE: 1:1
CVD SET SCREW
x 2
CENTER CVD BONE "FRONT"
x 1
CENTER CVD BONE "REAR"
x 1
CVD COUPLING
x 2
CENTER CVD INPUT SHAFT
x 2
1. SPREAD A SMALL AMOUNT OF BLACK GREASE ON THE OUTSIDE OF THE CVD COUPLING AND INSERT THE
COUPLING INTO THE AXLE AS SHOWN.
2. SPREAD A SMALL AMOUNT OF BLACK GREASE ON THE ROUND PORTION OF THE AXLE AND INSERT INTO THE
CVD BONE, ALIGNING THE CROSS HOLES.
3. INSERT THE CROSS PIN, MAKING SURE IT IS EVENLY SPACED ON BOTH SIDES OF THE CVD BONE.
4. APPLY A SMALL AMOUNT OF MIP THREAD LOCKING COMPOUND TO THE SET SCREW. ANGLE AND TURN
THE CVD SO THE SET SCREW CAN BE SCREWED IN WITH AN ALLEN WRENCH.
5. REPEAT THIS PROCEDURE FOR BOTH FRONT AND REAR CENTER CVD'S.
CENTER CVD ASSEMBLY:
CENTER CVD COMPONENTS
CVD CROSS PIN
x 2
APPLY A SMALL AMOUNT
OF BLACK GREASE
CVD CROSS PIN
SOLID
APPLY A SMALL AMOUNT OF
THREAD LOCKING COMPOUND
STEP 6
CENTER CVD BAG
STEP 7
PAGE 7

DOWEL PIN
x 2
ATTENTION!
* (E-CLIPS ARE LOCATED IN THE SHOCK BAG)
INPUT SHAFT COMPONENTS
SMALL E-CLIP*
x 2
INPUT SHAFT SHIM
x 8
DRIVE PINON
x 2 3/16 x 3/8
BEARING
x 4
CAREFULLY TRIM ANY BURRS
FROM THIS EDGE OF THE DRIVE
PINION WITH A HOBBY KNIFE.
1. SLIDE TWO INPUT SHAFT SHIMS AND TWO 3/16 X 3/8 BEARINGS ONTO
THE INPUT SHAFT.
2. SLIDE TWO INPUT SHAFT SHIMS ONTO THE INPUT SHAFT.
3. INSTALL AND CENTER THE DOWEL PIN INTO THE INPUT SHAFT.
4. TRIM BURRS FROM THE DRIVE PINION EDGE WHERE SHOWN.
SLIDE THE DRIVE PINION ON TO THE INPUT SHAFT. MAKE SURE THE
DOWEL PIN ALIGNS PERFECTLY WITH THE SLOT IN THE PINION.
5. ADD THE SMALL E-CLIP.
6. REPEAT THIS PROCEDURE FOR THE OTHER INPUT SHAFT.
COMPARE ASSEMBLY:
INPUT SHAFT ASSEMBLY:
INPUT SHAFT SHIM
x 4
DRIVE PINON
x 1
DOWEL PIN
E-CLIP
3/16" x 3/8" BEARING
x 2
INPUT SHAFT
1. COMPARE YOUR ASSEMBLY CAREFULLY!
2. COMPLETE OTHER INPUT SHAFT ASSEMBLY TO MATCH.
CENTER CVD BONE "FRONT"
(SHOWN)
CENTER CVD BONE "FRONT" (SHOWN)
BAG C
STEP 8
STEP 9
PAGE 8

TRANSMISSION COMPONENTS
8°
FRONT TRANSMISSION HOUSING REAR TRANSMISSION HOUSING
4-40 x 5/16"
BUTTON HEAD
x 2
4-40 x 3/8"
BUTTON HEAD
x 4
4-40 x 3/8"
FLAT HEAD
x 6
4-40 x 3/8"
SOCKET HEAD
x 8
4-40 x 1/8"
SET SCREW
x 2
1. ATTACH THE FRONT, LOWER TRANSMISSION HOUSING TO THE CHASSIS
AND FRONT BULKHEAD USING TWO 4-40 x 5/16" BUTTON HEAD SCREWS
IN THE FRONT AND TWO 4-40 x 3/8" FLAT HEAD SCREWS IN THE BACK.
2. ATTACH THE REAR, LOWER TRANSMISSION HOUSING
TO THE REAR OF THE CHASSIS USING FOUR 4-40 x 3/8"
FLAT HEAD SCREWS.
3. TEMPORARILY SCREW A 4-40 x 1/8" SET SCREWS INTO
EACH SIDE OF THE REAR SUSPENSION MOUNT (FRONT).
LATER IN THE ASSEMBLY, IT WILL BE NECESSARY TO TIGHTEN
THESE SET SCREWS AGAINST THE REAR HINGE PINS.
A SMALL AMOUNT OF THREAD LOCKING COMPOUND
WILL BE ADDED AT THAT TIME.
TRANSMISSION CASE ASSEMBLY:
4-40 x 3/8"
FLAT HEAD
x 2
4-40 x 5/16"
BUTTON HEAD
x 2 4-40 x 3/8"
FLAT HEAD
x 4
4-40 x 1/8"
SET SCREW
x 2
BAG C
STEP 10
PAGE 9