Maintenance Information; Troubleshooting - Sym Jet 50 Service Manual

9. CRANKCASE/CRANKSHAFT

Maintenance Information

This chapter concerns disassembly of the crankcase for repair purpose.
Before disassembling crankcase, except removing engine firstly, following components must be
removed too.
Carburetor (chapter 10)
¡ E
Oil pump (chapter 3)
¡ E
Reed valve (chapter 10)
¡ E
Driving belt (chapter 7)
¡ E
Alternator (chapter 6)
¡ E
Cylinder head/cylinder/piston (chapter 5)
¡ E
Except above components are needed be removed, when disassembling L crankcase, following
components must be removed too.
Final driving mechanism (chapter 8)
¡ E
When assembling both crankcase and crankshaft, it has press the inner ring edge of the
crankshaft bearing to push the crankshaft into the crankcase hole by using the specified service
tools. The old bearing onto the crankshaft has to be removed. Then install a new bearing onto the
crankshaft on the crankcase side. Oil seal has to be replaced with new one after assembled the
crankcase.
Lateral clearance of the big end of the connecting rod
Radial clearance of the big end of the connecting rod
Crankshaft run-out point A
Crankshaft run-out point B
Special Tools
Crankcase disassemble tool (SYM-1120100-G5)
Outer bearing puller (SYM-6204010)
R. Crank shaft puller (SYM-1130000-R)
R. Crank shaft install bush (SYM-1130020)
L. Crank shaft puller (SYM-1130000-L)
L. Crank shaft install bush (SYM-1130010)
20*32*6 Oil seal driver (SYM-9120200)
Bearing driver 6204 (SYM-9110400)

Troubleshooting

Engine noise
1. Worn bearing of connecting rod bog end
2. Bend connecting rod
3. Worn crankshaft bearing
9-2
This chapter Contents
Item Standard Limit (mm)
¢ w
¢ w
¢ w
¢ w
0.60
0.04
0.10
0.10