New Zongshen RX3 (ZS250GY-3) Dual Sport

[SpudRider]

Okay, I think the port for accessing the crankshaft is in the traditional location. The port is located in the center of the stator cover.





I was confused, because this port is not visible in the photograph shown below.

[Weldangrind]

It would certainly be a benefit to replace the cover, for access to the crank access port.

[Weldangrind]

Originally Posted by SpudRider

I haven't seen evidence to the contrary, so I believe the NC250 engine is a Zongshen design.

The NC250 engine has a single, overhead camshaft. This engine has two intake and two exhaust valves. The centrally located cam actuates the valves via two roller rocker arms.

I'm not crazy about roller rockers; I can't tell for sure, but it looks like needle bearing rollers in those rockers. They have a tendency to fail and spit out needles.

I do like the conventional tappets. Much easier than shim and bucket.

[Weldangrind]

Originally Posted by recracer

Oil filter lower right side

I've never seen an oil filter like that. Has anybody else?

[SpudRider]

Originally Posted by Weldangrind

I'm not crazy about roller rockers; I can't tell for sure, but it looks like needle bearing rollers in those rockers. They have a tendency to fail and spit out needles.

I do like the conventional tappets. Much easier than shim and bucket.

The RX3 valve rockers look very similar to the valve rocker in my CRF250X.

[SpudRider]

Originally Posted by Weldangrind

It would certainly be a benefit to replace the cover, for access to the crank access port.

My best guess is the display engine is not functional, and it omitted the crankshaft port to better display the Zongshen label. Photographs of the Minsk TRX 300i show the access port.

[Weldangrind]

Roller rockers are very popular in small block Chev motors, but they fail with catastrophic results.

[Weldangrind]

Originally Posted by SpudRider

My best guess is the display engine is not functional, and it omitted the crankshaft port to better display the Zongshen label. Photographs of the Minsk and Honley bikes show the access port.

That's good news. It would be a nuisance to remove the cover to set the engine at TDC.

[SpudRider]

Originally Posted by Weldangrind

That's good news. It would be a nuisance to remove the cover to set the engine at TDC.

Instead of removing the stator cover, I would turn the rear wheel in sixth gear. However, it's impossible to look through the timing window using that method. Since the timing window appears to be located on the front edge of the stator cover, the crankshaft port must be located in the middle of the stator cover.

[SpudRider]

Originally Posted by Weldangrind

Roller rockers are very popular in small block Chev motors, but they fail with catastrophic results.

That is good, and interesting information. Fortunately, I haven't heard of any failures of the Honda, CRF roller rockers.

[SpudRider]

Originally Posted by Weldangrind

I've never seen an oil filter like that. Has anybody else?

Yes, I have seen photographs of long oil filters such as the RX3 oil filter.

[SpudRider]

I'm now sure the crankshaft port is located in the center of the stator cover. Here is a photograph of a replacement stator cover.



Here is another photograph of a functional engine.

[SpudRider]

Originally Posted by recracer

The megelli was the 6-speed . I'll need to look ,but I am sure the ratios were in the megelli thread . As I had made sprocket changes to it.

The Zongshen RX3 apparently has a 13T/44T sprocket combination from the factory. Here is the 13T C/S sprocket.

http://item.taobao.com/item.htm?spm=...01&ns=1#detail





Here is the 44T rear sprocket.

http://item.taobao.com/item.htm?spm=...3-47d16eb8caf4



The stock, 520 drive chain has 110 links.

http://item.taobao.com/item.htm?spm=...3-47d16eb8caf4

[Weldangrind]

Those sprockets look like CRF parts.

[Weldangrind]

Originally Posted by SpudRider

Yes, I have seen photographs of long oil filters such as the RX3 oil filter.

I didn't ask my question properly. What I meant was, has anybody seen a long filter like that used in a motorcycle engine? If so, what make of bike?