Zongshen RX3: Flywheel, Stator, Engine Counter Balancer, and OCS

[SpudRider]

Flywheel

The magnetic flywheel is located on the left end of the crankshaft, and is located inside the red circle in the photograph below. In conjunction with the stator and regulator/rectifier, the flywheel generates the electricity which charges the motorcycle's battery. If you need to replace the camshaft timing chain, you will need to remove the flywheel.

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/flywheel%20and%20balancer%20gears_zps2i7dopyi.jpg (http://s442.photobucket.com/user/spudrider/media/Zongshen%20RX3/flywheel%20and%20balancer%20gears_zps2i7dopyi.jpg. html)

Removing the Flywheel and Stator

Drain the motor oil, then remove the stator cover. The stator is installed inside the stator cover, as shown inside the orange oval of the photograph below. Disconnect the stator wires from the wiring harness before removing the stator cover. Also remove the hose for the oil contaminant separator (OCS), which is shown inside the yellow circle in the photograph below.

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/oil%20contaminant%20separator_zpsay3wwdhj.jpg (http://s442.photobucket.com/user/spudrider/media/Zongshen%20RX3/oil%20contaminant%20separator_zpsay3wwdhj.jpg.html )

Secure the flywheel with a flywheel holder, such as the one shown below.

http://i442.photobucket.com/albums/qq146/spudrider/Zong%20Engine%20Rebuild%2051687%20Miles/HighlineBSBandZongrebuild095.jpg

Hold the flywheel, and remove the 28 mm nut and washer. To remove the flywheel from the crankshaft, you will need a flywheel puller tool. The Zongshen RX3 uses the same flywheel puller as the latest models of the Honda CRF250R, and CRF450R motorcycles; it has Motion Pro part #08-0372.

http://www.motionpro.com/motorcycle/partno/08-0372/

https://ff3d8e6495061f28a832-a7869bbdcfcea96a643a5d6aa79482f7.ssl.cf1.rackcdn.c om/enlarged/08-0372.jpg

You can also purchase the same flywheel puller from other manufacturers, with different part numbers. For example, this Tusk Flywheel Puller will work as well. ;)

https://www.rockymountainatvmc.com/p/925/-/1059577/Tusk-Flywheel-Puller-28mm?v=8973

https://images.rockymountainatvmc.com/images/prod/400/t/tus_15_fly_pul-28mm.jpg

Tighten the 28 mm barrel of the flywheel puller to the threads on the counter shaft. Hold the 28 mm barrel with a wrench, and tighten the bolt of the flywheel puller until the flywheel separates from the counter shaft.

After the flywheel is removed you will have easy access to the timing chain sprocket, and the camshaft timing chain.

[SpudRider]

Left Oil Pump Inspection

Whenever you remove the flywheel, be sure to inspect the rotors of the left oil pump, which is located inside the orange oval in the photograph below.

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/flywheel%20and%20balancer%20gears_zps2i7dopyi.jpg

If either rotor is worn, replace both rotors in that pump. The rotors wear together as a matched pair, and both rotors should be replaced at the same time.

Oil is the lifeblood of an engine. If either oil pumps fails, engine damage is likely to occur.

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/left%20oil%20pump%20uncovered_zpstlyyeyn9.jpg

[SpudRider]

Counter Balancer Gears: Inspection/Removal

While the flywheel is removed, you should also inspect the gears of the counter balancer. If either gear is worn, replace both gears. Before removing the gears, you must lock the gears together. You can do this with a penny, or you can use a tool such as the Motion Pro GearJammer.

http://www.motionpro.com/motorcycle/partno/08-0427/

https://ff3d8e6495061f28a832-a7869bbdcfcea96a643a5d6aa79482f7.ssl.cf1.rackcdn.c om/enlarged/08-0427.jpg

https://ff3d8e6495061f28a832-a7869bbdcfcea96a643a5d6aa79482f7.ssl.cf1.rackcdn.c om/enlarged/08-0427_alt2.jpg

After the gears are locked, remove the nuts and washers from both gears. If necessary, remove the woodruff key from the counter shaft. You must also remove the camshaft timing gear from the crankshaft.

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/left%20crankase%20bare_zpsv0jolbct.jpg (http://s442.photobucket.com/user/spudrider/media/Zongshen%20RX3/left%20crankase%20bare_zpsv0jolbct.jpg.html)

[SpudRider]

Counter Balancer Gears and Flywheel Installation

Place the gears on the counter balancer and crankshaft. Be certain to align the dots on the two gears, as shown by the yellow arrows and yellow dots in the photographs below.

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/counter%20balancer%20gear%20alignment_zpsyhjk10l4. jpg (http://s442.photobucket.com/user/spudrider/media/Zongshen%20RX3/counter%20balancer%20gear%20alignment_zpsyhjk10l4. jpg.html)

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/flywheel%20and%20balancer%20gears_zps2i7dopyi.jpg (http://s442.photobucket.com/user/spudrider/media/Zongshen%20RX3/flywheel%20and%20balancer%20gears_zps2i7dopyi.jpg. html)

Replace the camshaft timing gear on the crankshaft. Replace the washers and nuts on both shafts, and lock the gears. Tighten both nuts with a torque of 63 foot-pounds (85 Nm).

If necessary, replace the woodruff key on the counter shaft. Replace the flywheel. Replace the nut and washer over the flywheel. Secure the flywheel with a flywheel holder, and tighten the nut with a torque of 63 foot-pounds (85 Nm).

Replace the stator cover. Reconnect the stator wires to the wiring harness. Reconnect the hose to the oil contaminant separator (OCS). Fill the engine with 1.7 quarts of motor oil.

[SpudRider]

Oil Contaminant Separator (OCS)

The oil contaminant separator (OCS) vents gasoline fumes, water vapor and other contaminants from the engine's crankcase. The shaft of the engine's counter balancer is hollow, and contaminated fumes exit the crankcase through holes in the counter balancer weight. These holes are shown inside the red oval in the photograph below.

http://i442.photobucket.com/albums/qq146/spudrider/Zongshen%20RX3/oil%20contaminant%20separator_zpsay3wwdhj.jpg (http://s442.photobucket.com/user/spudrider/media/Zongshen%20RX3/oil%20contaminant%20separator_zpsay3wwdhj.jpg.html )

The counter balancer vents the fumes to a port on the stator cover. A hose on the front of the stator cover conducts the fumes to the oil contaminant separator (OCS), the black capsule shown inside the yellow circle in the photograph above.

Please note, the OCS was installed incorrectly, in an inverted position as shown in the photograph above. ;) The hose should connect to the top of the OCS, and the mounting clip should be located at the bottom of the OCS, as shown in the photograph below. If your OCS is inverted, remove it, and install it as shown in the photograph below. Otherwise you will collect excess fuel in the clear tube beneath the OCS. ;)

http://californiascooterco.com/blog/wp-content/uploads/2015/07/140701_4723-650.jpg

It is normal, and good, for the OCS to collect condensed fuel vapors which have evaporated from the crankcase. When the tube fills with condensed water and fuel vapors, remove the plug at the bottom of the tube to drain the contaminants for a safe, environmental disposal.