Detailed instructions for use are in the User's Guide.
[. . . ] HEAD OFFICE(FACTORY) #58, SUNG SAN-DONG, CHANG WON, KYUNGNAM, KOREA TEL: (82-55) 239-7000 / FAX: (82-55) 239-7520 OVERSEAS SALES OFFICE(FACTORY) 13-5, SEONGSU 1-GA, 2DONG, SEONGDONG-GU, SEOUL, KOREA TEL: (82-2) 3408-2634 / FAX: (82-2) 467-9997
SERVICE MANUAL
2007. 01 PUBLICATION
COPY PROHIBIT
HOW TO USE THIS MANUAL
This manual describes effective maintenance procedure for the VJF125 manufactured by DAELIM Motor Co. , Ltd. To ensure safety and optimal operating conditions of the vehicle, carry out regular inspections according to the maintenance schedule (Section 2). Sections 1 through 2 provide information on overall vehicle; and section 3 describes maintenance procedure for the engine, frame and electrical systems. [. . . ] Rotate the reamer clockwise, never counterclockwise when inserting and removing.
TOOL : VALVE GUIDE REAMER
Measure and record each valve guide inner diameter.
SERVICE LIMIT : 5. 030 mm
Measure the guide-to-stem clearance with a dial indicator while rocking the stem in the direction of normal thrust.
SERVICE LIMIT : IN : 0. 080 mm EX: 0. 100 mm
Measure the inner diameter of the new valve guide. If the clearance is not within the service limit, replace the valve.
VALVE GUIDES REPLACEMENT
Refinish the valve seats whenever the valve guides are replaced to prevent uneven seating. Use temperature indicator sticks, available from welding supply stores, to be sure the cylinder head is heated to the proper temperature.
10-6
CYLINDER HEAD / VALVES
Using a torch to heat the cylinder head may cause warping.
Wear insulated gloves to avoid burns when handling the heated cylinder head. Support the cylinder head and drive the old guides out of the combustion chamber side of the cylinder head.
TOOL : VALVE GUIDE DRIVER
Avoid damaging the head when driving the valve guide out. Drive the new guide in from the camshaft side of the cylinder head while the cylinder head is still heated.
TOOL : VALVE GUIDE DRIVER
When reaming new valve guides, insert the valve guide reamer from the combustion chamber side.
TOOL : VALVE GUIDE REAMER
Take care not to tilt or lean the reamer in the guide while reaming. Otherwise, the valve is installed slanted, that causes oil leaks from the stem seal and improper valve seat contact and results in the valve seat refacing not able to be performed. Rotate the reamer clockwise, never counterclockwise when inserting and removing. Reface the valve seats and clean the cylinder head thoroughly to remove any metal particles.
VALVE SEATS INSPECTION / REFACE
Clean all intake and exhaust valves thoroughly to remove carbon deposits. Tap the valve against the valve seat serveral times with the valve guide reamer, without rotating the valve, to check for proper valve seat contact. The valve seat contact should be within the specified width and evenly all around the circumference. If the valve seat width is not within specification, reface the valve seat.
10-7
CYLINDER HEAD / VALVES
Valve faces and stem tips cannot be ground. If a valve face or stem tip is rough, worn unevenly, or contacts the seat improperly, the valve must be replaced. Measure the valve seat width.
STANDARD VALUE : 0. 7~0. 9 mm SERVICE LIMIT : 1. 3 mm
VALVE SEAT VALVE SEAT VALVE SEAT VALVE SEAT
VALVE SEAT REFACING
70 20 IN : 22mm EX : 22mm IN : 23mm
Reface the worn valve seat by using valve seat cutters and grinders.
Follow the refacer manufactuer's operating instructions. Be careful not to grind the seat more than necessary.
IN : 24. 5mm EX : 24. 5mm EX : 20mm
ROUGHNESS OR SCRATCH
Using a 45 degree cutter, remove any roughness or irregularities from the seat.
Reface the valve seat whenever the valve guide has been replace.
VALVE SEAT 45
Using a cutter, remove material.
of the existing valve seat
SERVICE LIMIT : IN : 20 degrce cutter EX : 30 degrce cutter
CUT THE SEAT PART
35
10-8
CYLINDER HEAD / VALVES
Using a 70 degree cutter, remove the bottom old seat.
OLD SEAT WIDTH
of the
70
Using a 45 degree cutter, cut the seat to the proper width.
VALVE SEAT WIDTH : 0. 9~1. 1mm
SEAT WIDTH
45
CONTACT TOO HIGH
OLD SEAT WIDTH
Apply a light coating of Prussian Blue to each valve face. Tap the valve against the valve seat serveral times with the valve guide reamer, without rotating the valve, to check for proper valve seat contact. If the contact area is too high, grind the seat using cutter as like.
IN : 20 degree , EX : 30 degree flat cutter
35
Refinish the seat to specifications, using a 45 degree finish cutter.
If the contact area is too low on the valve, grind the seat using 70 degree cutter. .
CONTACT TOO LOW
Refinish the seat to specifications, using a 45 degree finish cutter.
OLD SEAT WIDTH
60
10-9
CYLINDER HEAD / VALVES
After cutting the valve seat, apply lapping compound to the valve face, and insert the valve with a valve guide reamer.
Do not excessively press and turn the valve to set it as it may cause damage. The seat surface may become worn on one side if the valve is set in the same position. Take precautions not to allow compound to get into the clearance between the stem and guide while the valve is being set.
CYLINDER HEAD ASSEMBLY
Install new stem seals with valve spring seat. Lubricate each valve stem with molybdenum grease and insert the valve into the valve guide turning a valve too fast can damage the stem seals. Check to see if the valve move up and down smoothly.
Install the valve springs with the narrow pitch forward to cylinder head.
FOR CYLINDER HEAD FOR CYLINDER HEAD FOR CYLINDER HEAD
Install the spring retainer. Compress the valve springs and install the valve cotters.
Do not compress the valve spring more than necessary when installing the valve cotters may cause loss of valve spring tension.
TOOL : VALVE SPRING COMPRESSOR
VALV E SPRING COMPRESSOR VALV E SPRING COMPRESSOR VALV E SPRING COMPRESSOR 10-10
CYLINDER HEAD / VALVES
Tap the valve stems gently with a soft hammer to firmly seat the cotters.
Take necessary precautions not to damage the valve.
Install the cam chain tensioner, and assemble pivot bolts.
TORQUE : 1. 0 kgf m (10N m)
Install the spark plug.
TORQUE : 1. 1 kgf m (11N m)
CYLINDER HEAD INSTALLATION
Clean any gasket material from the cylinder mating surface. (Install in the remove order of removal)
When install the `cylinder head special socket nut' (M8 1. 25), tighten them for 2~3times(Refer to the upper picture) half installation Complete installation Complete installation Complete installation Complete installation
TORQUE : 2. 0 kgf m
10-11
CYLINDER HEAD / VALVES
After checking the comshaft for damage, put it to the cylinder head. [. . . ] Incorrect valve timing.
Clogged
Damaged fuel strainer or screen. Poor carburetor maintenance.
21-2
TROUBLESHOOTING
INSPECTION
9. Overheated Contaminated or discolored
CAUSE OF TROUBLE
Lean fuel mixture. Incorrect ignition timing.
Level low or high
Valve train lubricated improperly.
13. [. . . ]