Zongshen RX3: Sprocket Carrier Modification

[rjmorel]

Riceburner "Or, rjmorel, since your a machinist, what do you think?"
Well, I guess it's kind of a wash which way you do it.
If you bore the sprocket, you'll have to bore them every time you replace the sprocket. But can still run the OEM one.
If you turn the carrier like Spud did, then your good to go except for using the standard sprocket again if I understand him right. For my intended use just switching back and forth between the 13T and 14T countershaft sprocket does what I want so far. Mainly pavement and gravel fire roads. rj

[SpudRider]

You can have the best of both worlds, if you buy a spare sprocket carrier, and modify it. Then you will have a wide variety of sprockets available, from many different vendors, and you can switch back and forth between the two sprocket carriers as you please.

For someone living outside the United States, I think it is advantageous to modify the sprocket carrier, even if you don't get a spare sprocket carrier. Zongshen only has the stock, 44T sprocket available. Someone outside the U.S. will have to pay international shipping costs to get custom sprockets from CSC. However, they can purchase the JT Sprockets, or the Suzuki DR200 sprockets, et cetera, from a wide variety of vendors. The JT Sprockets are readily available in 39T, 40T, 41T, 42T, 44T, 45T, 46T, and other sizes, from many international sources.

I don't want to keep repeating the variety of sprockets available; it is tiring. If someone takes the time to read this entire thread, they will see all the options available to them. If someone just wants to read the last few posts, that's fine, but I am not going to keep repeating all the information shown in the first page of this thread.

[SpudRider]

Also, if someone outside the U.S. merely wants a 44T sprocket, he still needs to get it from the local distributor, or from Taobao. If the local distributor has poor customer service, he is out of luck. If he needs the sprocket quickly, he won't enjoy the delay associated with a Taobao purchase. However, Suzuki sprockets, et cetera, are widely available from a wide variety of sources. It is always good to have more options when you need to purchase something.

[SpudRider]

Also, you don't need to take the sprocket carrier to a machinist to modify it. The sprocket carrier is manufactured from aluminum, which is relatively easy to cut/file. I modified my spare sprocket carrier with an angle grinder. One could also use a dremel tool, or even a file, to modify the sprocket carrier. Perform this simple modification once, and you never have to do it again. Once the mod is completed, you will have access to a wide variety of different size sprockets from a wide variety of different international vendors.

[humanbeing]

Originally Posted by SpudRider

Also, you don't need to take the sprocket carrier to a machinist to modify it...

Riceburner is living in Philippines. Machinist's rate is quite reasonable by US standard.
Cost of safety gear & "usable" power tool IS higher than US.

[Riceburner]

Thanks Spud for the mod info. When I get my 46 sprocket Maybe I'll have also gotten the carrier, if not I'll modify my existing one. Hope to get to the city tomorrow and check on the Suzuki DR200, see if I can get it local.

I'll also look up that other Zong carrier on Taobao.

When I ordered the 13 C/S I ordered two so I can have my own back up stock, will do the same with the 46, get two.

For me the delay with Taobao is shorter than the delay from my dealer. Ordering from CSC or eBay could work for some small parts and have sent to family in Las Vegas and they can put together a small box send other cool stuff we can't get here, that reduces my overall shipping cost, still expensive so I only do it three times a year.

I will build my small parts supply stash.

Again thanks SpudRider and everyone else that has contributed to all this great info,

[SpudRider]

Originally Posted by rjmorel

...If you turn the carrier like Spud did, then your good to go except for using the standard sprocket again if I understand him right...

Actually, the Zongshen sprocket will fit on the sprocket carrier after the modification. However, there will be a 2 mm gap between the inside bore of the sprocket, and the core of the sprocket carrier. This gap might allow the Zongshen sprocket to shift on the carrier, since only the six bolts are available to prevent lateral movement.

A machinist could easily fabricate a ring with a thickness of 6 mm, an inside diameter (i.d.) of 64 mm, and an outside diameter (o.d.) of 68 mm. Six millimeters is the thickness of a size 520 sprocket. This adapter ring could be installed around the core of the sprocket carrier when using the stock sprocket, and would prevent lateral movement of the sprocket. The adapter ring could be removed from the modified sprocket carrier when using JT sprockets.

To prevent this adapter ring from popping off the sprocket carrier, you would only need to add 6 fender washers under the nuts which attach the sprocket to the sprocket carrier. The stock bolts are long enough to accommodate washers underneath the nuts, and the washers would be much stronger than necessary to prevent the adapter ring from popping off the sprocket carrier.

This inexpensive adapter ring would allow an RX3 owner to easily, and quickly switch between Zongshen sprockets, and JT sprockets as desired.

[SpudRider]

Does anyone know of any tube, gasket, et cetera, which has an i.d. of 64 mm, and an o.d. of 68 mm? A tube with the proper dimensions could easily be cut into rings with a thickness of 6 mm.

Here is some tubing with the proper dimensions sold by Spahr Metric, Inc., of Winchester, VA.

http://metric-steel.spahrmetric.com/...08-68-02-064-0

[rjmorel]

Just to be a wise @$$ I remember back a few years somebody came up with oblong chain ring sprockets for bicycles. They were suppose to add power by multiplying the power on the pedal down stroke when the oblong part came around. Or something like that.
Ergo if you put the OEM sprocket on Spuds modified carrier and let it be off center and adjust it so it is timed with the piston power stroke I'm sure you would gain a good amount of free horsepower.
While this theory dizzies the mind with calculations for various tire sizes, and how many times the engine revolution actually matches up with the rear sprocket oblong thingy ,it does sound solid. But then my doctor says I'm do in for a few more shock treatments so what do I know? rj

[SpudRider]

Perhaps a hub centric ring, 67x 64.15 mm, will fill the space properly.

http://www.automotivepartsfactory.co...-50983840.html



http://www.ebay.com/itm/like/1712315...chn=ps&lpid=82

[SpudRider]

Originally Posted by rjmorel

Just to be a wise @$$ I remember back a few years somebody came up with oblong chain ring sprockets for bicycles. They were suppose to add power by multiplying the power on the pedal down stroke when the oblong part came around. Or something like that.
Ergo if you put the OEM sprocket on Spuds modified carrier and let it be off center and adjust it so it is timed with the piston power stroke I'm sure you would gain a good amount of free horsepower.
While this theory dizzies the mind with calculations for various tire sizes, and how many times the engine revolution actually matches up with the rear sprocket oblong thingy ,it does sound solid. But then my doctor says I'm do in for a few more shock treatments so what do I know? rj

[SpudRider]

One could also trim, or machine, depending on the material, a slightly large, 69mm OD x 64.15mm ID, hub centric ring.

http://www.brandsport.com/grla-69-64...FQ9rfgod6q0CyA

[SpudRider]

However, I'm happy to have a spare, modified sprocket carrier. I can easily switch between the two sprocket carriers, whenever I like.

[Riceburner]

Spud, RJ and Jay in Milipitas, you guy's crack me up (LMAO)

Originally Posted by rjmorel

Just to be a wise @$$ I remember back a few years somebody came up with oblong chain ring sprockets for bicycles. They were suppose to add power by multiplying the power on the pedal down stroke when the oblong part came around. Or something like that.
Ergo if you put the OEM sprocket on Spuds modified carrier and let it be off center and adjust it so it is timed with the piston power stroke I'm sure you would gain a good amount of free horsepower.
While this theory dizzies the mind with calculations for various tire sizes, and how many times the engine revolution actually matches up with the rear sprocket oblong thingy ,it does sound solid. But then my doctor says I'm do in for a few more shock treatments so what do I know? rj

Having a back up OEM carrier seems like a good idea. As I said, I don't really expect to run a 44, a 45 or 46 is more what I need for the trips into the back country, some of the roads and hills are very steep. I've killed three clutch sets on my little YBR125G going where I don't belong and I had to do that "coast" down hill, "push up" to get back to a semi main road so I could be towed to the town square and transported by truck home. Don't want to be pushing that heavy Zong up any hills.

I need to be able to go back to Brgy. Victoria, Tubungan, Iloilo (http://www.panoramio.com/photo/80527698) and see if I can get Dennis's parents to allow him to have surgery and that road, trail is one of the worst, probably the "WORST" trip I've ever done (the coast/push trip) and from all the comments I'm sure the stock 14/44 isn't going to make; 13/44 maybe but 13/45 or 46 I'm going for it.

And there is Brgy. Dao, Seven Cities, Alimodian and three kids I need to go get for the next mission and those are some nasty roads, hills, river crossing, mud, sand rocks.... FUN, FUN, FUN

Spub, I'm taking a print out of those sprockets you've shared and going to see if I can get them in the city this morning, thanks man.

[SpudRider]

You're welcome.

JTR811

http://www.jtsprockets.com/catalogue/sprocket/JTR811-48



This sprocket fits the Suzuki DR200SE motorcycle, and is available for sale in the United States in 39T, 45T and 46T configurations.