Zongshen Sierra 200GY-2 Crankcase Cover Mod

[SpudRider]

The 196cc engine of the Zongshen Sierra 200GY-2 is a very close copy of the Yamaha TW200 motorcycle engine, with one major difference. The Yamaha TW200 uses a very fat rear wheel; therefore, the Yamaha employs a very long countershaft that must be supported by a bearing in the left crankcase cover. The support for this bearing is located inside the yellow circle shown in the photograph below.



In order to support this extra long countershaft and bearing, the left crankcase cover is a solid unit. Therefore, if you wish to inspect, clean or replace the countershaft sprocket, you must first remove the entire left crankcase cover. Also, if you wish to inspect or replace the countershaft oil seal or gearshift lever oil seal, you must first remove the entire left crankcase cover.

Since the front half of the crankcase cover contains engine oil, the crankcase cover employs a gasket. Therefore, removing the left crankcase cover always involves the loss of some engine oil, and it could damage the gasket.

The Zongshen Sierra 200GY-2 copies the Yamaha crankcase cover very closely. The outside of the left crankcase cover for the Zongshen 200GY-2 is shown in the photograph below.



The Zongshen Sierra 200GY-2 is not an exact copy of the Yamaha TW200. One major difference is that the Zongshen motorcycle employs a narrower rear tire than the Yamaha TW200. Therefore, the Zongshen uses a shorter countershaft, which does not require the bearing or its support.

I like to remove my Tsubaki 428HQR drive chain at every oil change and scrub it with kerosene. After I dry the drive chain, I then soak it in the used engine oil before I reinstall in on the motorcycle. Removing and replacing the drive chain is possible without removing the left crankcase cover, but it is a bit of a nuisance. I wanted to be able to reinstall the Zongshen’s drive chain more easily; I also wanted to be able to clean and inspect the countershaft sprocket without having to remove the entire left crankcase cover. Therefore, I decided to modify the Zongshen 200GY-2 left crankcase cover.

First I ordered an extra left crankcase cover from Zongshen America. After the crankcase cover arrived I examined it; I determined that a single saw cut could separate the front and rear sections of the cover without compromising the oil seal in the front. I took the crankcase cover to a local machinist, and he made the section shown below.



I can now remove the rear of the crankcase cover without disturbing the engine’s electrical system mounted in the front of the crankcase cover. I can also remove the rear section of the crankcase cover without the risk of damaging the engine gasket, or losing engine oil.

I will replace my original left crankcase cover with the modified cover when I make my next oil change.



Spud

[Jim]

Looks good, good tip for zongshen owners, thanks

[SpudRider]

Originally Posted by Jim

Looks good, good tip for zongshen owners, thanks

Thank you, Jim.

The extra left crankcase cover only cost me $25 USD (United States dollars). The local machinist did not charge me anything.

Spud

[katoranger]

That cut could easily be made on a bandsaw too. Probably what the machinest used.

Great tip. The lifan already uses a separate cover I believe.

Allen

[SpudRider]

Originally Posted by katoranger

That cut could easily be made on a bandsaw too. Probably what the machinest used.

Great tip. The lifan already uses a separate cover I believe.

Allen

Yes, I believe the machinist did use a bandsaw.

I don't own a bandsaw, so after I determined the best section line on my crankcase cover I started looking in the yellow pages and on the internet for a local machinist. I found a lot of big, specialized machine shops; however, I could not find the small, friendly, one-man operation I was looking for.

Then I remembered that the local university has a College of Technology with a Computerized Machining program. :idea: :roll: I called the department head and asked if he could refer me to a local machinist. After I described the job, he told me a bandsaw would probably work well. Then he told me to bring the cover to his classroom shop and he would cut it for me.

He was busy when I arrived, so I did not get to watch him make the cut. He told me to come by the next day and pick it up. Needless to say, he did a superb job, and nobody will beat his price.

Spud

[SpudRider]

Originally Posted by katoranger

That cut could easily be made on a bandsaw too. Probably what the machinest used.

Great tip. The lifan already uses a separate cover I believe.

Allen

Allen, you got me thinking about this subject some more. If a Zong rider doesn't own a bandsaw, I imagine the local high school shop teacher would probably cut the crankcase cover for him. :idea: :wink:

Spud

[SpudRider]

Spring is arriving in Idaho, and I want to ride every chance I get. Therefore, I decided today that it was time for another oil change, and it was also time to make my left crankcase cover modification.

I easily removed the left crankcase cover, but I had to coax it a little because of the magnetic attraction between the rotor and the stator. I tried to carefully preserve the crankcase cover gasket, but it was attached with a small amount of adhesive at the factory; therefore, I could not avoid damaging it. I replaced the gasket with a new one I had purchased from Zongshen America.

I removed the stator and pickup coil from the old crankcase cover and installed them into the front portion of my modified cover.



After installing the new crankcase cover gasket, I attached the front portion of the modified cover. I now have very nice access to my countershaft sprocket, countershaft oil seal and shift lever oil seal.



I was planning to replace my countershaft sprocket, but I discovered that Zongshen America had sent me the wrong sprocket. I also discovered that my Sierra 200GY-2 has a 15-tooth sprocket instead of the 14-tooth sprocket specified by Zongshen. :roll: The Sierra 200GY-2 employs a Yamaha TW200 countershaft sprocket, which is available in a variety of sizes from seven different manufacturers. I plan to order a PBI 50-733-15 sprocket, and replace my countershaft sprocket as soon as possible.

Two bolts solidly attach the rear of the modified crankcase cover. Since these bolts are long, I must also remove the gearshift lever before I can remove my modified rear crankcase cover.



My Zong is now ready to ride for the summer! After my new 15-tooth sprocket arrives, I can now easily replace the old sprocket without needing to remove the entire left crankcase cover.



Spud

[Cal25]

Nice job and great write-up. Noticed the stand in the last pic it looks like a nice tool to have. Gets me to thinking about another welding project.

[frostbite]

This is gettin' a sticky..

[SpudRider]

Originally Posted by Cal25

Nice job and great write-up. Noticed the stand in the last pic it looks like a nice tool to have. Gets me to thinking about another welding project.

Originally Posted by frostbite

This is gettin' a sticky..

Thank you, gentlemen.

The swingarm stand is manufactured and sold by T-Rex. It is well built, works great, and I don’t know how I ever got along without it.

Spud

[max_damage]

Great mod :wink:

[SpudRider]

Originally Posted by max_damage

Great mod :wink:

Thank you, Max. I hope you are well and enjoying your Zong in Croatia.

Anyone interested in learning more about Zongshen 200GY-2 sprockets will probably enjoy reading the following thread:

http://chinariders.net/modules.php?n...ewtopic&t=7565

This thread contains a comprehensive listing of the various countershaft sprockets currently available for the Zongshen Sierra 200GY-2.

Spud

[SpudRider]

Forum member Fishman10 posted the following information.

Originally Posted by fishman10

by the way ,i had a friend who assured me he could do the left side case cut with a sawsall , so i trusted him and he showed me how its done .He did a real nice and straight job by screwing the side case down to his workbench! Just another reason why having someone look at it with a fresh set of eyes can make you say , why didn't I think of that.

I am sure this information will help other Zongites; thank you, Fish!

Spud

[fishman10]

not quite as nice a job as spud's,, but remember this was done with a sawsall.

[FastDoc]

I think it looks great.