KEEWAY RKV125 User Manual

XIII Cylinder Block and Piston
Preparatory data------------ 13.1 Piston---------------------- 13.4
Fault diagnosis--------------13.2 Cylinder installation----- 13.5
Cylinder block-------------- 13.3
13.1 Service Data
Precautions on Operation
All the components shall be cleaned before inspection and test, and purged with high-pressure air.
Function of cylinder block: Cylinder block provides the space for gas compression, combustion
and expansion and guides piston movement. It also transfers part of heat in the cylinder to
surrounding coolant.
Function of piston:
Piston can bear the pressure generated by combustion of mixed combustible gas in the cylinder and transmit the
pressure to connecting rod to drive crankshaft to rotate.
It forms a combustion chamber with cylinder head.
It works as a slide valve to compress regularly fresh mixed gas from crankcase into cylinder and exhaust combustion
gas from the cylinder.
Basic data Unit: mm
Item
Standard Value
Service Limit
Cylinder
ID
57-57.01
57.10
Cylindricity
0.005
0.05
Roundness
0.004
0.05
Flatness
0.02
0.05
Piston OD(measuring point)
56.987-56.977
(8mm at the bottom of piston skirt)
56.93
Piston pin hole ID
14.002-14.008
14.04
Piston pin OD
13.994-13.997
13.96
Clearance between piston and piston pin
0.005-0.014
0.05
Clearance between piston ring and ring groove
Top ring
0.020-0.060
Second ring
0.020-0.060
Joint clearance of piston rings
Top ring
0.25-0.35
Second ring
0.20-0.35
Oil ring
0.20-0.70
Connecting rod small end ID
14.010-14.018
14.06
Clearance between linkage rod and piston pin
0.013-0.024
0.10

KEEWAY RKV125 Specifications

General

Engine Type	Single cylinder, 4-stroke, air-cooled
Fuel System	Carburetor
Transmission	5-speed
Front Suspension	Telescopic fork
Front Brake	Disc
Rear Brake	Drum
Cooling System	Air-cooled
Seat Height	770 mm
Weight	135 kg
Fuel Tank Capacity	17 L
Rear Suspension	Dual shock absorbers