Zongshen 200GY-2: Fork Service at 41,922 Miles

[SpudRider]

The weather was unseasonably warm this week, so I seized the opportunity to service the forks on my Zong, which has almost 42,000 miles on the odometer. The wind was blowing, the day was short, and the job was messy, so I didn't take many photographs. However, I will supplement this thread with photographs borrowed from other sources.

As far as I know, no one else has ever posted a thread regarding servicing the Zongshen 200GY-2 forks, so I was heading into unfamiliar territory. My fork oil seals were leaking, so I wanted to replace the fork oil seals and the dust wipers when I changed the fork oil. However, the last time I checked, Zongshen America did not sell fork oil seals. :roll: Therefore, I measured the fork diameter, and the dimensions of the dust wipers, in an effort to determine the correct replacement seals. Based upon my measurements, I was pretty sure my Zong employed 37x50x11mm oil seals. Therefore, before I began the job, I ordered fork oil seals and dust wipers for the '09 Honda CRF150R. After separating the fork tubes, I was pleased to discover I had ordered the correct parts.

The Zongshen Service Manual for my bike is almost complete fiction regarding the motorcycle's forks. :roll: I did not know the correct fork oil, or the correct volume of fork oil to use as a replacement. :( Therefore, I decided to measure the depth of the fork oil before I disassembled the forks, and also to measure the fork oil I drained from the forks.

After doing quite a bit of research, I decided I would use Mobile1 Synthetic ATF for my new fork oil. I also surmised that each fork would probably require 200ml of fork oil. I had no idea what the fork oil level would be once I opened the forks. :roll:

After removing the left fork, I unscrewed the fork cap. After lowering the outer fork tube, I separated the fork cap from the damping rod by using a 12mm wrench to hold the damping rod nut, and a crescent wrench to unscrew the fork cap. The Zongshen factory used a lot of red loctite to glue the fork cap to the damping rod! 8O Therefore, I needed to use a large crescent wrench, and lots of effort to separate the fork cap from the damping rod. :roll:

Once the fork cap was off, I pushed down on the preload spacer, and removed the washer that keeps the damping rod extended. I was then able to remove the preload spacer, and the preload spacer bushing. Reaching in with a small hook, I removed the fork spring, and placed it on a clean towel with the other parts. Allowing the outer fork tube to collapse, I looked inside the fork to measure the oil level. I was surprised to discover the oil was 11.5-inches below the upper edge of the inner fork tube. 8O

Pushing the damping rod repeatedly, I drained all the oil from the fork, and measured 200ml of dirty fork oil. Laying the fork horizontally on a table, I lowered the dust wiper, and removed the fork seal retaining clip. I expected to encounter resistance as I disassembled the fork tubes, but I was surprised when the inner fork tube separated easily from the outer fork tube, leaving the oil seal, and all the bushings inside the outer fork tube! :?

Laying the inner fork tube aside on a clean cloth, I examined the outer fork tube. I pried the old oil seal from the outer fork tube with a flat blade screwdriver, being careful not to scratch the surface of the tube. Then I removed the oil seal washer, and cleaned the inside of the outer fork tube.



I examined the inner fork bushing, which was placed at the bottom end of the outer fork tube, just past the fork seal washer. The outer fork bushing appeared to be located about half way down the interior of the outer fork tube, so I could not inspect it.

Having completed every possible task with the outer fork tube, I now inspected the inner fork tube and the internal parts I had removed from the fork. As expected, the fork components were similar to those in photographs I had encountered earlier, during my research.



The bushing on the preload spacer was in good condition, and the fork spring also appeared to be in good shape. I did not remove the cartridge from my fork, as forum member David3921 did in the following photograph.



Having measured the oil level, and the drained oil I had collected, I compared the old oil seals and dust wipers to my new replacement parts. So far, all was well, so I cleaned the fork parts before I started to rebuild the first fork.

Spud

[SpudRider]

After cleaning the oil seal washer, I re-installed it in the bottom of the outer fork tube. Since the outer fork tube bushing was located inside the outer fork tube, I was able to drive the new fork oil seal into place with a hammer. After pressing the new oil seal into place by hand, I placed the old fork seal on top of it to cushion the hammer blows. When the new oil seal was almost seated, I used a rubber mallet to finish driving the oil seal to its fully seated position. Here’s a photograph of the outer fork leg with the new oil seal installed in it.



If you examine this photograph closely, you can see the inner fork bushing located in the fork tube, just inside the oil seal. Looking farther inside the fork tube, you can see the outer fork bushing located inside the fork tube, about half way down the tube. The outer fork bushing appears to be held in place by the long, split metal sleeve, which is supported by the inner fork tube bushing.

The inner fork bushing was easy to inspect, and it was in excellent condition. This bushing would also be easy to replace; I assume it is a Honda bushing. Since the bushing on the fork preload spacer was also in excellent condition, I decided not to remove the outer fork bushing for inspection. Apparently, you must remove the inner fork bushing and the long, split, metal sleeve from the lower part of the outer fork tube in order to remove, and replace the outer fork bushing.

Spud

[SpudRider]

After I installed the oil seal retaining clip, I placed the new dust wiper on the inner fork tube. I then carefully slid the inner fork tube into the outer fork tube, and pressed the dust wiper into position by hand. Since the damper rod is difficult to grab when it is fully compressed, I next secured a zip tie under the locking nut on the damper rod. The zip tie gave me something to grab after the damper rod was fully compressed in the fork leg.

I placed the reassembled fork tube on a mat, and added 200ml of Mobile1 Synthetic ATF to the fork assembly. After sliding the two fork tubes, and repeatedly working the damping rod up and down, I filled the damper cartridge with ATF. I worked the damper rod up and down until all air was expelled from the cartridge, and the rod action was smooth. Next I measured the oil level by inserting a long zip tie into the inner fork tube. I confirmed the oil level was 11.5-inches from the top before I reinstalled the fork spring.

After installing the fork spring, I extended the damping rod and removed the zip tie. Holding the damping rod in an extended position, I installed the preload spacer bushing, and the preload spacer. With the damping rod extended, I pushed down on the preload spacer and attached the spacer washer under the damping rod.

I applied one drop of red loctite to the threads on the end of the damping rod. Using a 12mm wrench, I held the nut on the damping rod as I tightened the fork cap onto the end of the rod with a crescent wrench. Finally, I raised the outer fork tube, and tightened the fork cap into the end of the fork, completing the fork assembly.

Spud

[SpudRider]

I removed the second fork from the bike, and performed the same maintenance procedures on it. I completed the job more quickly now that I understood the construction of the Zongshen forks.

I re-installed both forks in the triple tree, and lightly tightened a single pinch bolt on each side of the bottom of the triple tree. Next I inserted the front axle in both forks to ensure the forks were aligned, and I would be able to re-install the front wheel. If the front axle doesn't install easily, loosen one of the pinch bolts and get the forks aligned before you tighten them into position.

Once the forks were aligned, I applied some red loctite to the lower pinch bolts, and torqued them to 24 foot pounds. Then I tightened the fork caps, applied red loctite to the upper pinch bolts, and torqued them to 20 foot pounds.

After re-installing the front wheel, I lowered the bike from the jack, and the job was completed. Since the sun was setting, I stored the bike for the evening, and cleaned up my work area.

Spud

[SpudRider]

The next day I took my Zong for a ride to do some grocery shopping. Previously my forks would dive a bit while braking; I'm pleased to report the diving has now disappeared. My forks are performing very well, and I am very glad I decided to employ Mobile1 Synthetic ATF for my new fork oil.

Spud

[Weldangrind]

Thanks for the detailed write-up, Spud. Do you think that you've lost much oil over 40000 miles due to leakage? What research led you to 200ml of oil?

[SpudRider]

Originally Posted by Weldangrind

Thanks for the detailed write-up, Spud. Do you think that you've lost much oil over 40000 miles due to leakage? What research led you to 200ml of oil?

No, I don't think I've lost much fork oil, Weld. I measured the oil collected from both forks, and each measured 200ml. Also, page 82 of the LZX200GY-2 Service Manual (Europe) lists the volume of fork oil as 200ml, plus or minus 10ml.

http://www.chinariders.net/transfer/...ice_Manual.pdf

The Zongshen Service manual supplied with my motorcycle lists the volume of fork oil as 150ml, plus or minus 10ml. However, I was pretty sure this volume of oil was too low. :roll:

The Qinqi/Qlink bikes specify 330ml of fork oil, but the Qinqi forks are larger in diameter than the Zongshen forks, and the Qinggi forks have greater travel. Therefore, I anticipated the fork oil volume would probably be 200ml, and this figure was confirmed when I collected 200ml of oil from each fork.

I can easily add more oil if the current volume of oil proves to be too low. I am certainly interested to hear from others who think the correct volume of oil in my forks should be greater than 200ml. So far, however, my forks are working better than ever, so I am reluctant to add more oil without compelling evidence.

Spud

[SpudRider]

Here are the detailed, step-by-step instructions for changing the fork oil, and installing new oil seals and dust wipers on your Zongshen 200GY-2 forks.

Changing Fork Oil, Oil Seals and Dust Wipers on Zongshen Forks

Gather Tools Required for the Job:

Torque Wrench
Allen Head Sockets
Socket Wrench, and Socket Set
Flat Blade Screwdriver, jeweler’s screwdriver
Open end wrench set
Crescent Wrenches
Zip Ties
Throw Rug
Shop rags and paper towels
Large zip tie, or other, thin measuring device 12-inches long (oil depth is 11.5-inches)
New fork seals and dust wipers (Honda 51490-GBF-J21)
New fork Oil
Rubber Mallet and Hammer
Grease
Small zip ties
Oil collection pan
Empty, 1-quart oil bottle (used to measure oil drained from the forks)

Each fork takes 200mm of ATF/fork oil
Torque values: Bottom Pinch Bolts, 20 foot-pounds; Top Pinch Bolts, 20 foot-pounds

Disassembly of Forks

Remove lower fork protectors and front brake caliper; hang caliper from motorcycle frame.
Loosen the front axle
Place jack under engine, and lift bike
Remove front wheel

Perform maintenance on the first fork

Loosen top pinch bolt of triple tree on one fork
Loosen cap on fork tube
Loosen bottom pinch bolts of triple tree, and slide fork down, and out of triple tree
Unscrew the fork cap. Using a 12mm wrench, hold the damping rod nut, and remove the fork cap with a large crescent wrench.

Push down on the preload spacer, and remove the preload spacer washer.
Remove the preload spacer, the preload spacer bushing, and the spring from the outer fork tube. Place these items on a clean cloth.

Note that the narrow coils of the spring are at the top of the fork.

Push the fork tubes together. Push the cartridge all the way down into the fork.
Using a zip tie, or other, thin measuring device, confirm the distance from the top of the inner fork tube to the oil level in the tube is 11.5-inches.

Place the top of the fork tube over a waste oil pan, and pour out the old fork oil. Pump the lower tube to remove more oil.
Turn the fork upright, and attach a zip tie to the end of the damping rod.
Pump the cartridge up and down to expel the oil from it into the oil collection pan.
Repeat these steps until all the oil is removed from the cartridge, and the fork tube.

Using the fork tubes as a slide hammer, separate the inner and outer fork tubes, and drain the remaining oil into the oil pan.

Confirm the amount of oil expelled from each fork is 200 ml by pouring it into an empty, one-quart, oil bottle.

Place the inner fork tube on a clean cloth.

Lay the Upper, outer fork tube horizontally on a table. Remove the dust wiper, then remove the fork seal retaining clip from the fork.

Using a flat blade screwdriver, pry out the old oil seal.

Remove, and clean the oil seal washer
Clean the inside of the upper fork tube, and inspect all bushings.

Clean the preload spacer, and the preload spacer bushing.
Inspect the preload spacer bushing.

Measure the length of the fork springs (20.5 inches)

Inspect both fork tubes for scratches, dents or abnormal/excessive wear.

Clean the surface of the inner fork tube.

Assembly of Fork Tubes

Install the oil seal washer inside the upper fork tube
Lubricate the inside and outside edges of the new, fork oil seal.
Use the old oil seal to pound the new oil seal into place.
Install the oil seal retaining clip.

Lubricate the inside, and the outside of the new dust wiper
Lubricate the edge of the inner fork tube
Install the dust seal on the inner fork tube.
Assemble the fork tubes, and set the dust wiper in place with your fingers
Put the fork right-side-up on a rug, and fully compress the tubes

Using a funnel, add 200mm of ATF to the inner fork tube.
Extend and compress the fork several times.
Slowly extend, and compress the damper rod, about ten times, until the action is smooth, and all air has been removed from the cartridge.

Make sure the damping rod and the fork tubes are fully compressed.
Measure the depth of the oil level. The oil level should be 11.5-inches from the top of the inner fork tube.
If necessary, add or remove fork oil.

Install the fork spring.
Extend the damping rod, and remove the zip tie from the damping rod
Install the preload spacer bushing and preload spacer into the fork, and quickly retrieve the end of the damping rod.

Push down on the preload spacer, and insert the preload spacer washer under the damping rod nut.
Apply red locktite to the damping rod threads
Screw the fork cap onto the damping rod, and tighten the nut.
Raise the outer fork tube, and install the fork cap into the fork tube.

Repeat all these procedures for the second fork.

Reinstall the forks in the triple tree

Install one fork into the triple tree. Align the end of the outer tube with the upper surface of the triple tree. Slightly tighten one of the bottom pinch bolts on the triple tree.
Using the method above, install the second fork.

Install the front axle to make sure the forks are aligned, and you will be able to reinstall the front wheel! If the axle will not fit, loosen the pinch bolt on the higher of the two forks until the axle slips in, then retighten the pinch bolt.

Apply red loctite to the lower pinch bolts on both forks, and torque to 20 foot-pounds.

Tighten the caps on both forks.
Apply red loctite to the upper pinch bolts on both forks, and torque to 20 foot-pounds.

Install front wheel
Lower the front of the bike to the ground.
Install front brake caliper and lower fork protectors.

Finally, log onto China Riders, and add a post to this thread detailing your experience changing the fork oil.

Spud

[FastDoc]

Very intersting thread Spud. Well thought out and well executed repair.

[SpudRider]

Originally Posted by FastDoc

Very intersting thread Spud. Well thought out and well executed repair.

Thank you, Brother Bill.

Spud

[SpudRider]

I just added this thread to the Zong Sticky, under the Maintenance subheading.

Spud

[FastDoc]

I respect the time and effort you put in to help others Spud. :wink:

[MICRider]

Originally Posted by FastDoc

I respect the time and effort you put in to help others Spud. :wink:

+1! Excellent write up Spud!

[SpudRider]

Originally Posted by FastDoc

I respect the time and effort you put in to help others Spud. :wink:

Thank you, Brother Bill. I feel the same about you. Please check your messages; I am going to send you a PM.

Spud

[SpudRider]

Originally Posted by MICRider

+1! Excellent write up Spud!

Thank you, Stew.

Today I was working on my Honda XR650L; I installed a rebored cylinder and oversized piston. Therefore, I didn't get to ride the Zong today. However, I did ride the Zong yesterday, and the forks feel great! So far the Mobile1 Synthetic ATF is performing superbly as fork oil.

The '09 Honda, CRF150R, fork seal set I installed was exactly the same size as the original, Zongshen, fork seal set. The Zongshen, fork oil seal had the following information printed on it:

JN 51103
37 50 11

This fork oil seal has an inside diameter of 37mm, an outside diameter of 50mm, and is 11mm thick.

The Zongshen dust wiper had the following information printed on it:

JN 51112
37 50.3 13

This dust wiper has an inside diameter of 37mm, an outside diameter of 50.3mm, and a width of 13mm.

The Honda, fork seal set, part #51490-GBF-J21, is identical to the original, Zongshen, fork seal set.

Spud