RX3 Lubrication System: Checking the Engine Oil Level

[SpudRider]

The lubrication system of the NC250 (ZS177MM) engine in the Zongshen RX3 is designed similarly to the lubrication system of my Honda XR650L. Both systems use a dual chamber oil pump, which has an elevated oil reservoir. The Honda stores much of its engine oil in a reservoir located at the top of the bike's frame, behind the triple tree. The Zongshen stores much of its engine oil in a 'gearbox' reservoir, located behind the bike's clutch cover. The Honda has an oil dipstick located at the elevated reservoir, and the Zongshen has an sight glass located at the elevated reservoir. The level of oil in the elevated reservoir is not constant for either motorcycle, so both bikes require you to follow a specific procedure to make sure you measure the oil level properly.

In this thread I will first describe the design of the Honda lubrication system, then I will describe the similar design of the Zongshen lubrication system. Finally, I will describe the proper method to check the oil level, which is almost identical for both bikes, since the lubrication systems are designed so similarly.

[pete]

The RX3 is a wet sump motor & the XR650 is a dry sump motor ?






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[SpudRider]

I will describe the Honda lubrication system first, since I have a detailed diagrams of that system, and that system is thoroughly described in Honda literature. Once we understand the Honda lubrication system, we can better understand the Zongshen lubrication system.

Let's describe the Honda lubrication system starting at the oil sump, which is the lowest part of the engine where all the oil drains after it has lubricated the upper parts of the engine. Here is a drawing which shows how the 2-chamber oil pump lubricates the Honda engine, and stores much of the oil in an elevated reservoir.



The first chamber of the oil pump draws oil from the oil sump, and delivers the oil to two locations. One line sends oil to the transmission, which then drains back to the oil sump. The other line sends oil to the upper oil reservoir.

The upper oil reservoir then delivers oil by gravity feed to the second chamber of the oil pump. The second chamber of the oil pump delivers oil to the oil filter. After the oil is filtered, the oil is separated into two lines. One oil line lubricates the crankshaft, connecting rod, and piston. The other oil line sends oil to the cylinder head to lubricate the camshaft, rocker arms, and valve tappets. After lubricating the top of the engine, all this oil drains to the oil sump, where the entire cycle begins again.

[SpudRider]

The Zongshen lubrication system is described in the CSC blog at the following link.

http://californiascooterco.com/blog/?p=17257



As described in the CSC blog, the Zongshen oil system has two oil reservoirs. As with the Honda system, the lower 'reservoir' is the oil sump, or crankcase, where all the oil collects after lubricating the top end of the engine. The upper reservoir is the 'gearbox,' which contains the sight glass, and is located behind the clutch cover.

I don't have a detailed description of the Zongshen system, but I surmise it operates in a manner similar to the Honda system. The NC250 (ZS177MM) engine has two oil pumps. One oil pump probably collects oil from the oil sump. It then delivers oil to lubricate the transmission, and also stores oil in the upper reservoir, which is labeled the 'gearbox.' This upper reservoir, and the sight glass, are located high above the oil drain plug, which is near the oil sump at the bottom of the engine.

From the elevated, 'gearbox' reservoir, oil is probably fed by gravity to the second oil pump, which delivers oil to the oil filter. From the oil filter the oil probably follows two oil lines. One oil line lubricates the crankshaft, connecting rod, and piston. The other oil line goes to the cylinder head to lubricate the camshaft, rocker arms, and tappets. All of this oil then drains to the oil sump, and the process is repeated.

[SpudRider]

Because the upper oil reservoirs in both systems are fed by the first chamber of the oil pump, the oil level in these reservoirs changes under different operating conditions. Therefore, you must follow a specific procedure to properly determine the actual oil level in the reservoir. The proper procedure is described exactly the same for both the Honda and Zongshen engines.

The Honda manuals tell you to check the oil level when the engine is warm, after it has reached operating temperature. Let the bike idle for a minute or two on the kick stand, in an upright position. Then turn off the engine, and wait a minute or two for the oil to drain. Finally, balance the bike in a vertical position, and measure the oil level on the dipstick.

The CSC blog tells you to check the oil level in the following words.

Allow the engine to come up to operating temperature.
Close the throttle and allow the engine to operate at idle for one minute.
Close the ignition and wait for one minute.
Hold the motorcycle in the vertical position (i.e., off the sidestand) and observe the engine oil level in the viewport. If the engine has the right amount of oil, the level will be between the upper and lower scribe lines, as shown in the photo below.

[SpudRider]

If you don't follow the proper procedure with either the Honda XR650L, or the Zongshen RX3, you will probably overfill the engine with motor oil. The RX3 will blow the excess oil out the crankcase vent, and the excess oil will collect in the tube below the oil separator, as described in the following thread.

http://www.chinariders.net/showthrea...883#post188883

[SpudRider]

I usually check the oil level in both my RX3 and XR650L after I finish a ride. I also will sometimes check the oil level during a ride, when I stop to fill the fuel tank. In both cases, the engine has reached operating temperature. After letting the engine idle for several minutes on the kick stand, I stop the engine. Then I balance the bike in the vertical position, and check the oil level.

If I check the oil at a gas station, I let the bike idle on the kick stand for a minute or two beside the pump. Then I turn off the engine, and pump the fuel while the oil settles. After pumping the fuel, I balance the bike in the vertical position, and check the oil level.

If you fill the RX3 with the specified, 1.7 quarts of motor oil at each oil change, you will have the proper amount of oil in the crankcase. You can verify the engine is not burning oil, or leaking oil, by checking the oil level in the manner described above.

http://www.cscmotorcycles.com/Articles.asp?ID=266

[SpudRider]

Originally Posted by pete

The RX3 is a wet sump motor & the XR650 is a dry sump motor ?

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Based upon the information provided by CSC, and the Zongshen engineers, the Zongshen engine has two oil reservoirs, and the upper reservoir contains the oil measuring device. As you can see in the photographs below, the oil sight glass is located very high above the oil sump, oil drain plug, both oil screens, and the oil filter. Also, you must check the oil level using the same procedure as you do for the Honda motorcycle. Therefore, I must conclude the two lubrication systems are similar in many ways.

[SpudRider]

Also, it's nice to note the NC250 engine holds 1.7 quarts of motor oil, which is almost the same amount of motor oil (2.06 quarts) as contained in the much larger, 650cc engine of the Honda XR650L.

[pete]

Originally Posted by SpudRider

Also, it's nice to note the NC250 engine holds 1.7 quarts of motor oil, which is almost the same amount of motor oil (2.06 quarts) as contained in the much larger, 650cc engine of the Honda XR650L.

same amount of oil as my XT660R... like the XR the oil
is in a tank for a time away from the heat sorce "motor"



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[SpudRider]

Yes, the Honda, 'dry sump' lubrication system is a very nice design. The NC250 engine is water cooled, so an external oil reservoir is not necessary with the Zongshen engine.

I must say, I am very impressed with the nice condition of the used motor oil I empty from the NC250 engine.

[Weldangrind]

Excellent thread idea, Spud. You're an awesome Zong ambassador.

That's the same process I had to follow with my old '96 XR250R. A bit of a pain, but well worth the effort.

The intricate design of the oiling system helps to remind one of the importance of regular oil changes.

[SpudRider]

Thank you, Weld. I am impressed with the large oil volume for this 250cc engine. I change the oil every time the odometer records another 2,000 miles, which is the same schedule I keep for my Honda XR650L.

[SpudRider]

Today I reached 6,000 miles on the odometer, and changed the engine oil. I change the oil every time the odometer turns an additional 2,000 miles.

Since I switched to a reusable, stainless steel, oil filter, my RX3 now takes 1.8 quarts of motor oil, which is 1 quart plus 26 ounces.

[pete]

Originally Posted by SpudRider

my RX3 now takes 1.8 quarts of motor oil, which is 1 quart plus 26 ounces.

Whats are these quarts & ounces things you talk of ???





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