Zongshen 200GY-2: Engine Rebuild at 51,687 Miles

[Pliskin]

Originally Posted by SpudRider

Thank you for taking the initial gamble, and ordering parts from Taobao. :wink:

You are welcome Spud.

Originally Posted by SpudRider

However, my engine is running very strong, and I am very pleased with the results of my engine rebuild!

That's the main thing.

As always I appreciate all the documentation that you've done with great pics. Thank you for creating cost list.

Originally Posted by SpudRider

My parcel arrived in Idaho 4 days after being shipped from Hong Kong by DHL Express.

Very fast delivery.

[katoranger]

Forget 100,000km I am waiting on 100,000 miles.

I believe Spud holds the record for the highest mileage Chinabike in North America.

[FastDoc]

He's got more mileage on that little bike than I have on my Gold Wing.

[SpudRider]

Originally Posted by FastDoc

...Any pics of the valve seal install?

I'm sorry, I forgot to answer this question, Doc. :roll: No, I didn't take any photographs of my work on the cylinder head. However, I do have my old Zongshen cylinder head available, so I might take a few photographs of my tools, techniques, et cetera, when I get some time. Right now the riding weather is still too nice!

Here's a photograph of the Yamaha, XT200 valve rockers I removed. The intake rocker, on top, is in excellent condition. The damaged exhaust rocker was making an ominous noise in my cylinder head; I wonder why? :roll:



Since the Taobao prices are so wonderfully low, I decided to replace the camshaft as well as both valve rockers.

Spud

[SpudRider]

After the engine rebuild, my Zong is running stronger than ever! Here are a few photographs from yesterday's ride.













There's nothing wrong, if you own a Zong.

Spud

[SpudRider]

My Zong was very happy to be released from storage, and allowed once again to roam freely in the Rocky Mountains of Idaho. Can you spot my Zong in its native habitat?



Spud

[Weldangrind]

I don't think I'd walk that far from my Zong, if I was lucky enough to have one.

Thanks for the pics of the rockers, Spud. My guess is that's where the noise is coming from in my bike. Time to start shopping.

[SpudRider]

Originally Posted by Weldangrind

I don't think I'd walk that far from my Zong, if I was lucky enough to have one...

No one was going to steal my Zong from that location, Brother Weld. The wind was blowing pretty hard, so I even locked the forks to stabilize the bike while I was gone!

I climbed a little higher to enjoy an even better view of the surrounding terrain.











Spud

[SpudRider]

Originally Posted by Weldangrind

...Thanks for the pics of the rockers, Spud. My guess is that's where the noise is coming from in my bike. Time to start shopping.

You're welcome. You need a slide hammer to remove the rockers from the cylinder head. I also used a slide hammer to re-install the new rockers. Needless to say, I bought my slide hammer from Harbor Freight.

http://www.harborfreight.com/15-piec...-set-5469.html

This slide hammer also greatly facilitates the removal of the camshaft.

You can weld two bolts together to make a special tool which fits the screw adapter of the slide hammer and the threaded end of the bushing which holds the rockers in place. I will post photographs of my setup later, when I have time.

Spud

[Weldangrind]

That's a nice price; I've been thinking about buying a slide hammer for pulling dents out of old motorcycle gas tanks, and this clinches it.

Spud, can you confirm that the Zong rockers are totally identical to the XT parts? If so, I'm sure they'd be a perfect match for my TeeDub.

[SpudRider]

Originally Posted by Weldangrind

That's a nice price; I've been thinking about buying a slide hammer for pulling dents out of old motorcycle gas tanks, and this clinches it.

Spud, can you confirm that the Zong rockers are totally identical to the XT parts? If so, I'm sure they'd be a perfect match for my TeeDub.

Indeed, a slide hammer is a nifty tool to have around, and you can't beat that price. You definitely need a slide hammer to remove the valve rockers on the XT200/TW200/XT225/TT-R225/TT-R230 cylinder heads.

I installed Zongshen valve rockers in my XT200 cylinder head. The Zongshen valve rockers are identical to XT200 valve rockers, and are a perfect fit.



Spud

[SpudRider]

As promised, here are photographs showing how I removed my camshaft and valve rockers using the Harbor Freight slide hammer. I bought my Harbor Freight slide hammer on sale, for $20.

http://www.harborfreight.com/15-piec...-set-5469.html



The HF slide hammer has a 10mm screw adapter with fine threads on one side, and standard threads on the other side. I can weld, but I don't currently own a welder. Therefore, my Christian Brother Andy created two special adapters for me. The camshaft adapter has an M10 x 1.5 bolt for the camshaft welded onto a M10 x 1.25 bolt for the screw adapter. The rocker bushing adapter has an M8 x 1.25 bolt for the bushing welded onto an M10 X 1.25 bolt for the screw adapter. We needed to grind the rocker bushing adapter so it would fit inside the cylinder head.



After threading the appropriate adapter into the HF screw adapter, the slide hammer is ready. In the photograph below, the HF tool is configured to remove the camshaft.



The ends of the camshaft and rocker bushings are threaded to accept the special adapters. Here's a photograph of the adapters screwed into the cylinder head. After you attach the slide hammer, the camshaft and bushings are easy to remove.



In the next photograph the camshaft has been removed. After the camshaft is removed, it's possible to compress the valve springs and remove the valves without removing the rockers. However, compressing the valve springs is much easier after both the camshaft and valve rockers are removed.



After removing the rocker bushings, it's very easy to remove the valve rockers.

Spud

[Weldangrind]

Does the slide hammer come with a compression adapter? That's what you would attach to a stud that has no threads, similar in concept to a drill chuck.

[SpudRider]

No, this particular slide hammer does not come with a compression adapter.

Spud

[wilserchinarider]

Originally Posted by SpudRider

[

Spud, I am intrigued w/ this photo, and find it surprising the Zong was running w/ such a worn rocker?

Prior to the rebuild, did you notice constant valve adjustments were required for the exhaust valve to compensate for the wear that was occurring? Or do you think this happened over many miles and was just slowly compensated for in your routine valve adjustments?

That's the big advantage a seasoned pro mechanic has that works on a similar vehicle type repetatively, my dad used to joke that a sharp mechanic knew what the problem was as the vehicle was driven into the shop.