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

[Pliskin]

Spud thank you for documenting your work on forks. It will be of benefit to somebody i am sure. I've learned a lot from this thread. Nobody has done as many miles as you have, so no wonder oil seals gave up. I am getting a sense that you enjoy immensely working on your Zong. It must of taken you a lot of time to write the bit where you explain the tools and in what order to complete. Thank you for that. What i am trying to learn is, once you found out the dimensions of Zong's fork seals, how did you know that 09 Honda CRF150R was using the same fork oil seals? Does that mean that 09 Honda CRF150R employes the same forks as Zong?

[SpudRider]

Originally Posted by Pliskin

Spud thank you for documenting your work on forks. It will be of benefit to somebody i am sure. I've learned a lot from this thread. Nobody has done as many miles as you have, so no wonder oil seals gave up. I am getting a sense that you enjoy immensely working on your Zong. It must of taken you a lot of time to write the bit where you explain the tools and in what order to complete. Thank you for that. What i am trying to learn is, once you found out the dimensions of Zong's fork seals, how did you know that 09 Honda CRF150R was using the same fork oil seals? Does that mean that 09 Honda CRF150R employes the same forks as Zong?

You're welcome. Thank you for your kind words.

I truly love my Zong, Pliskin. It's a great little bike, and it doesn't cost much to keep it running. For example, when my starter motor failed at about 20,000 miles, I priced Yamaha starter motors. The retail price on the Yamaha part was $300, and the best discount price on the internet was $200. 8O I bought a new starter motor from Zongshen America for $45, and it has been running great even since.

Since no one had previously written a thread on Zongshen fork maintenance, I was heading into uncharted territory. Therefore, I researched general fork design, and also studied the Qingqi Service Manual for information on the Qingqi forks. I wrote the detailed instructions for myself so I could get the job done as quickly, and as smoothly as possible, even if I encountered something unusual. Therefore, I am happy to share my instructions with the hope they will help others in the future.

After I measured the dust wipers, I discovered all the 37mm x 50mm oil seals are 11mm thick. Searching the internet I found a list of all motorcycles that employ the 37mm x 50mm x 11mm, fork oil seals. The fork oil seals and dust wipers are the same for all these bikes, whether they employ conventional forks, or USD forks. Here is a partial list of the motorcycles that employ the same fork oil seals and dust wipers as my Zongshen 200GY-2 motorcycle:

CR-80R (96-02)
CR-85R (03-07)
CRF-150R (07-09)
CRF-150RB (07-09)
NX-250 (88-90)
XR-250R (81-82)

Suzuki RM-82 (02-04)

The 09 Honda CRF150R employs 37mm, fully adjustable, inverted, Showa cartridge forks with 10.8 inches of travel. These Showa forks are very different from my Zongshen forks, but both bikes still use the same fork oil seals and dust wipers.

I have subsequently discovered that many, if not most Chinese forks employ the same oil seals as my Zong. Indeed, I have also noticed a few Chinese bikes from other manufacturers which employ the identical forks I have installed on my Zongshen 200GY-2. Therefore, my instructions in this thread will also apply to many other Chinese motorcycles other than the Zongshen 200GY-2.

Spud

[SpudRider]

I went for a 35-mile ride today on the Zong; the odometer will soon reach 42,000 miles. The forks work great! I can certainly recommend the Mobile1 Synthetic ATF as fork oil.

When I get a chance, I will post some photographs of my old, fork oil seals and dust wipers. They were very dirty. My fork oil was pretty thin, and very dirty as well. Don't hesitate to change the fork oil in your Zongshen bike, or other Chinese motorcycle; you will be glad you did.

Spud

[Pliskin]

Thank you Spud for additional great information. It will be handy in the future for other chinariders.

Originally Posted by SpudRider

I went for a 35-mile ride today on the Zong; the odometer will soon reach 42,000 miles. Smile The forks work great! I can certainly recommend the Mobile1 Synthetic ATF as fork oil. Wink

Great to hear that Zong is riding better now.

[zingshoen]

goodonya spudrider, another worthwhile read for anyone interested in maintenance.
i did this for the xl185s a while ago and having new fork oil after 10+ years makes a lot of difference, i noticed a lovely soft rebound in particular. however, it took a bit of elbow grease to get the cover bolts back onto the forks while pushing the springs down. not impossible, but one needs to be strong.

so one question: was musclepower enough to force the springs back in or did u use a tool? or did i miss this in your description?

[SpudRider]

Originally Posted by zingshoen

goodonya spudrider, another worthwhile read for anyone interested in maintenance.
i did this for the xl185s a while ago and having new fork oil after 10+ years makes a lot of difference, i noticed a lovely soft rebound in particular. however, it took a bit of elbow grease to get the cover bolts back onto the forks while pushing the springs down. not impossible, but one needs to be strong.

so one question: was musclepower enough to force the springs back in or did u use a tool? or did i miss this in your description?

Thank you, Zingshoen. It was very easy to disassemble, and reassemble the Zongshen forks; one doesn't need to be very strong to do it.

Spud

[Weldangrind]

Originally Posted by zingshoen

goodonya spudrider, another worthwhile read for anyone interested in maintenance.
i did this for the xl185s a while ago and having new fork oil after 10+ years makes a lot of difference, i noticed a lovely soft rebound in particular. however, it took a bit of elbow grease to get the cover bolts back onto the forks while pushing the springs down. not impossible, but one needs to be strong.

so one question: was musclepower enough to force the springs back in or did u use a tool? or did i miss this in your description?

Unless you've swapped your forks for something else, they're conventional. I believe that Spud's forks are USD, so a somewhat different setup. I'm with you, Zingshoen; the springs are difficult to overcome in conventional forks. I haven't found a better way.

[SpudRider]

Originally Posted by Weldangrind

Unless you've swapped your forks for something else, they're conventional. I believe that Spud's forks are USD, so a somewhat different setup. I'm with you, Zingshoen; the springs are difficult to overcome in conventional forks. I haven't found a better way.

Among his other bikes, Zingshoen also has a Zongshen 200GY-2, Weld. Therefore, he won't have any difficulty installing the springs in his Zongshen forks.

I have never worked with conventional forks, so I am unfamilar with the difficultly involved with installing the springs in those forks. 8O

Spud

[Weldangrind]

Conventional forks, like those found on Zingshoen's XL185S, require that you compress the spring with the top cap, as you're trying to screw the cap in place. The only secret is to make sure that there is no load on the shock, so that the springs aren't fighting you anymore than necessary. The concern is that the cap is usually aluminum, and therefore it is easy to strip. You need to be patient.

[FastDoc]

Aluminum and fine pitch threads and a large diameter. All the ingredients to cross-threading :?

[SpudRider]

Originally Posted by Weldangrind

Conventional forks, like those found on Zingshoen's XL185S, require that you compress the spring with the top cap, as you're trying to screw the cap in place. The only secret is to make sure that there is no load on the shock, so that the springs aren't fighting you anymore than necessary. The concern is that the cap is usually aluminum, and therefore it is easy to strip. You need to be patient.

Thanks for the explanation, Brother Weld. Fortunately, the USD Zongshen forks are very easy to assemble.

Spud

[SpudRider]

Perhaps some forum members are wondering why I chose Mobile1 Synthetic ATF instead of a brand name, fork oil. My Zongshen service manual was not very helpful in this matter, since it recommended HQ-10 fork oil. :roll: Anticipating my fork oil change, I posted the following thread last summer, trying to determine the viscosity of HQ-10 fork oil.

http://www.chinariders.net/showthread.php?t=7786

According to the following chart, Mobile1 Synthetic ATF has a viscosity of 34 centistokes (cSt) at 40 degrees Celsius. Mobile1 Synthetic ATF is also reported to have good anti-foaming qualities, and will not damage rubber seals. In addition, Mobile1 Synthetic ATF is supposed to retain its viscosity significantly better with increasing temperature than many fork oils. The Viscosity Index (VI) in the following table indicates the stability of the oil viscosity over a wide range of temperature; bigger numbers are better when it comes to the Viscosity Index.

http://mahonkin.com/~milktree/motorcycles/fork-oil.html



Finally, Mobile1 Synthetic ATF is readily available, locally, in many auto parts stores; I bought a quart on Thanksgiving Day at my local AutoZone store.

Spud

[FastDoc]

I've done brain surgery with less research and thought, Brother Spud!

[SpudRider]

Originally Posted by FastDoc

I've done brain surgery with less research and thought, Brother Spud!

I know you are a very intelligent, well educated, and skilled physician, Brother Bill. I believe you are a doctor of internal medicine. Please remind never to have you perform neurosurgery on me!

Spud

[SpudRider]

Regardless of research, the real test of any fork oil comes when riding. The mountains of Idaho are covered with snow until next spring, so I am limited to riding on pavement for the winter. :( Nevertheless, the Mobile1 Synthetic ATF is working very well for me while riding on the street.

I have also read that some riders recommend rinsing the forks with ATF to clean them before installing new fork oil. Therefore, I decided to install the Mobile1 Synthetic ATF, and decline draining it to put in commercial fork oil.

Spud