User manual DAELIM HISTORY 125 SERVICE MANUAL

[. . . ] HOW TO USE THIS MANUAL This manual describes effective maintenance procedure for the SL125 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 3). Sections 1 through 3 provide information on overall vehicle; section 4, assembly and disassembly procedures for external components, and section 5 describes maintenance procedure for the engine, frame and electrical systems. To facilitate use of this manual, each page starts with disassembly and system diagrams, service information, and troubleshooting guide. [. . . ] Do not heat the cylinder head beyond 150° (300° C F). Use temperature indicator sticks, available from welding supply stores, to be sure the cylinder head is heated to the proper temperature. VALVE GUIDE VALVE GUIDE DRIVER CAUTION ·Using a torch to heat the cylinder head may cause warping. WARNING ·Wear insulated gloves to avoid burns when handling the heated cylinder head. 9-7 CYLINDER HEAD / VALVES Support the cylinder head and drive the old guides out of the combustion chamber side of the cylinder head. TOOL : VALVE GUIDE DRIVER CAUTION ·Avoid damaging the head when driving the valve guide out. Apply oil to a new O-ring and install it onto a new valve guide. Drive the new guide in from the camshaft side of the cylinder head while the cylinder head is still heated. TOOL : VALVE GUIDE DRIVER VALVE GUIDE DRIVER When reaming new valve guides, insert the valve guide reamer from the combustion chamber side. NOTE ·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. ·Use cutting oil on the reamer during this operation ·Rotate the reamer clockwise, never counterclockwise when inserting and removing. TOOL : VALVE GUIDE DRIVER VALVE GUIDE REAMER Reface the valve seats and clean the cylinder head thoroughly to remove any metal particles. VALVE SEATS INSPECTION Clean all intake and exhaust valves thoroughly to remove carbon deposits. Apply a light coating of Prussian Blue to each valve face. NOTE ·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. 9-8 CYLINDER HEAD / VALVES Remove the valve and inspect the valve seat face. 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. NOTE ·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. 8 -1. 0 mm SERVICE LIMIT : 1. 4 mm VALVE SEAT 37° VALVE SEAT REFACING Reface the worn valve seat by using valve seat cutters and grinders. NOTE ·Follow the refacer manufactuer's operating instructions. ·Reface the valve seat whenever the valve guide has been replaced. ·Be careful not to grind the seat more than necessary. 45° 55° 37° Using a 45 degree cutter, remove any roughness or irregularities from the seat. ROUGHNESS Using a 37 degree cutter, remove ¼ of the existing valve seat material. 37° 9-9 CYLINDER HEAD / VALVES Using a 55 degree cutter, remove the bottom ¼ of the old seat. 55° Using a 45 degree cutter, cut the seat to the proper width. SEAT WIDTH 45° If the contact area is too high on the valve, the seat must be lowered using a 37 degree flat cutter. Refinish the seat to specifications, using a 45 degree finish cutter. CONTACT TOO HIGH OLD SEAT WIDTH 37° If the contact area is too low on the valve, the seat must be raised using a 55 degree inner cutter. Refinish the seat to specifications, using a 45 degree finish cutter. CONTACT TOO LOW OLD SEAT WIDTH 55° 9-10 CYLINDER HEAD / VALVES After cutting the valve seat, apply lapping compound to the valve face, and insert the valve with a valve guide reamer. NOTE ·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. Turn the valve slightly when setting it. ·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. STEM SEAL NOTE ·Replace the stem seals with new ones whenever a stem seal is removed. Lubricate each valve stem with molybdenum disulfide grease and insert the valve into the valve guide. VALVE SPRING RETAINER COTTER CAUTION ·Turning a valve too fast can damage the stem seals. Install the spring seats, valve springs and retainers. NOTE ·For valve spring with varying pitch, install the valve springs with the narrow pitch end facing down. NARROW PITCH Compress the valve springs with the valve spring compressor and install the valve cotters. CAUTION ·Compressing the valve spring more than necessary when installing the valve cotters may cause loss of valve spring tension. TOOL : VALVE SPRING COMPRESSOR VALVE SPRING COMPRESSOR 9-11 CYLINDER HEAD / VALVES Tap the valve stems gently with a soft hammer to firmly seat the cotters. CAUTION ·Take necessary precautions not to damage the valve. Apply engine oil to the new O-ring, and assemble it to the carburetor insulator groove. Tighten the carburetor insulator with mounting bolts. Install the cam chain tensioner, and assemble pivot bolts. TORQUE : 1. 0 kgf ·m Install the spark plug. TORQUE : 1. 2 kgf ·m CARBURETOR INSULATOR Clean any gasket material from the cylinder mating surface. [. . . ] ·Faulty or contaminated spark plug. ·Disconnected or short high tension cord. ·Faulty valve clearance adjustment. Fuel is supplied Check the spark plug. Not contaminated or not discolored Contaminated or discolored. Insert the plug into cap, and check sparks. Weak or intermittent sparks. Sparks normal Measure the cylinder compression. (Using a compression gauge. ) Compression normal Low or no cylinder compression. Check the ignition timing. Correct Incorrect ·Faulty A. C generator. [. . . ]