Post by 90GTVert on Jul 19, 2016 13:51:59 GMT -5
This thread is full of all sorts of specifications for the most common Chinese GY6 125-150cc engines. There are variations in some engines (like GY6-B or P coded versions), and I don't know the ins and outs of every one, so it's always best to check your scooter before working on it or ordering parts for it. Use the info here at your own risk.
Bearings
Crankshaft(x2)
Camshaft(x2)
Primary Drive Shaft (Small Case Half)
Primary Drive Shaft (Large Case Half)
Counter Shaft (Small Case Half)
Counter Shaft (Large Case Half)
Rear Axle (Small Case Half)
Rear Axle (Large Case Half)
Seals
Crankshaft x2 (Left/CVT Side & Right/Stator Side)
Primary Drive Shaft
Rear Axle
Bushings
Engine Mount x2
Rear Shock Mount
Torque Specs
General Info
NGK Spark Plug Numbers : CR7HS, CR7HIX (iridium)
Spark Plug Gap : 0.024"-0.028" / 0.6mm-0.7mm
Valve Clearance/Lash : 0.002"-0.005" (Commonly Used : 0.002" Intake / 0.003" Exhaust)
Engine Oil Capacity : 0.75L
Engine Oil Viscosity : 10W40 or 15W40 (Motorcycle specific oil not necessary)
Gear Oil Capacity : 100-120mL
Gear Oil Viscosity : 75W90
Engine Oil Drain Plug : M12x1.5
Gear Oil Drain Plug : M8x1.25
Magnetic Drain Plug Kit At Amazon
Flywheel Puller : M27x1.0 LH
Flywheel Puller On Amazon
Random Bits
Exhaust Gasket
The standard ring exhaust gasket is approximately 30mm OD x 23mm ID x 3-4mm thick. The most common types are a composite or fiber and metal style or metallic ring gaskets. I've had issues with the composite type disintegrating, and had better luck with the metallic style.
Starter Clutch Nut
The starter clutch nut can be removed with a special tool, as shown. Searching for something like "GY6 starter clutch tool" should lead you to one. Another option is to use a chisel or punch in the indentations of the nut and strike it with a hammer to get it moving. The starter clutch nut is LH (left handed) thread. That means it does the opposite of a standard nut. Instead you turn it clockwise to loosen and counterclockwise to tighten.
Kick Start Gear
The kick start gear on the crankshaft can be difficult to remove with standard pullers. An armature bearing puller works well for me.
Bearings
Crankshaft(x2)
Number | I.D. | O.D. | Thickness |
SC04A86 | 22mm | 56mm | 15mm |
Camshaft(x2)
Number | I.D. | O.D. | Thickness |
6002-P6 | 15mm | 32mm | 9mm |
Primary Drive Shaft (Small Case Half)
Number | I.D. | O.D. | Thickness |
| 6204 | 20mm | 47mm | 14mm |
Primary Drive Shaft (Large Case Half)
Number | I.D. | O.D. | Thickness |
| 6301 | 12mm | 37mm | 12mm |
Counter Shaft (Small Case Half)
Number | I.D. | O.D. | Thickness |
| 6202 | 15mm | 35mm | 11mm |
Counter Shaft (Large Case Half)
Number | I.D. | O.D. | Thickness |
| 6002 | 15mm | 32mm | 9mm |
Rear Axle (Small Case Half)
Number | I.D. | O.D. | Thickness |
| 6203 | 17mm | 40mm | 12mm |
Rear Axle (Large Case Half)
Number | I.D. | O.D. | Thickness |
6004-RS | 20mm | 42mm | 12mm |
Seals
Crankshaft x2 (Left/CVT Side & Right/Stator Side)
I.D. | O.D. | Thickness |
19.8mm | 30mm | 5mm |
Primary Drive Shaft
I.D. | O.D. | Thickness |
20mm | 32mm | 6mm |
Rear Axle
I.D. | O.D. | Thickness |
27mm | 42mm | 7mm |
Bushings
Engine Mount x2
I.D. | O.D. | Thickness |
10mm | 28mm | 22mm |
Rear Shock Mount
I.D. | O.D. | Thickness |
8mm | 20mm | 19mm |
Torque Specs
Description | Torque |
Axle Nut (Rear Wheel) | 70-90ft-lb |
Clutch Bell Nut | 35-40ft-lb |
Clutch/Torque Driver Nut | 35-40ft-lb |
Cylinder Nut (x4) | 10-15ft-lb |
Flywheel Nut | 30-35ft-lb |
Variator Nut | 30-35ft-lb |
Thread Size | Torque |
M6 | 6-9ft-lb |
M8 | 10-20ft-lb |
General Info
NGK Spark Plug Numbers : CR7HS, CR7HIX (iridium)
Spark Plug Gap : 0.024"-0.028" / 0.6mm-0.7mm
Valve Clearance/Lash : 0.002"-0.005" (Commonly Used : 0.002" Intake / 0.003" Exhaust)
Engine Oil Capacity : 0.75L
Engine Oil Viscosity : 10W40 or 15W40 (Motorcycle specific oil not necessary)
Gear Oil Capacity : 100-120mL
Gear Oil Viscosity : 75W90
Engine Oil Drain Plug : M12x1.5
Gear Oil Drain Plug : M8x1.25
Magnetic Drain Plug Kit At Amazon
Flywheel Puller : M27x1.0 LH
Flywheel Puller On Amazon
Random Bits
Exhaust Gasket
The standard ring exhaust gasket is approximately 30mm OD x 23mm ID x 3-4mm thick. The most common types are a composite or fiber and metal style or metallic ring gaskets. I've had issues with the composite type disintegrating, and had better luck with the metallic style.
Starter Clutch Nut
The starter clutch nut can be removed with a special tool, as shown. Searching for something like "GY6 starter clutch tool" should lead you to one. Another option is to use a chisel or punch in the indentations of the nut and strike it with a hammer to get it moving. The starter clutch nut is LH (left handed) thread. That means it does the opposite of a standard nut. Instead you turn it clockwise to loosen and counterclockwise to tighten.
Kick Start Gear
The kick start gear on the crankshaft can be difficult to remove with standard pullers. An armature bearing puller works well for me.