Replacing gaskets

[hect75]

Chineros, I am in the process of engine assembling. I need to tight the cylinder hed bolts but I am confused. Zongshen uses cylinder head bolt 8-12 N.m, connecting bolt of cylinder head 10-12 N.m, and cylinder head nut 20-30 N.m. Yamaha TW200 recommends cylinder head bolts 22 N.m, socket head bolts 20 N.m, and bolts 10 N.m. Should I use only tw200 recommendation or zongshen?. By the way, I don´t know what exactly are connecting bolt of cylinder head and cylinder head nut (there is no figure).

Saludos

[SpudRider]

If you post photos of the bolts/nuts, we can help you to determine the torque values.

Since the two engines are virtually identical, I always use the Yamaha torque specifications.

[hect75]

Originally Posted by SpudRider

If you post photos of the bolts/nuts, we can help you to determine the torque values.

Since the two engines are virtually identical, I always use the Yamaha torque specifications.

I google the cylinder bolt and nut and they are the same as tw200. Thus, I will use yamaha specifications.

Gracias y Saludos

[SpudRider]

[hect75]

Hi, I assembled the engine but notice the cam chain tensioner is diferent from Spud´s one and that mentioned in tw200 service manual. I wonder if mine is incomplete since it does not have the bolt that spud´s tensioner has.





Also, I learned that the chain is very tight when installing the tensioner. I am confused since tw200 service manual recommends a 0.5 mm of tensioner rod position. Mine is about 0.11 mm and can´t adjust it ´til 0.5 mm. The next video shows the difference in tension when releasing the spring (tension cam chain) and when the spring is compressed (loose cam chain)

In other words, the tensioner can´t be adjusted.

[SpudRider]

The tensioner is automatic. When you release the screwdriver the tension is set properly. Your tensioner is working as it should.

You are missing the end bolt which keeps oil in the engine, and dirt from entering the engine. Can you find another bolt which fits the hole?

[hect75]

Originally Posted by SpudRider

The tensioner is automatic. When you release the screwdriver the tension is set properly. Your tensioner is working as it should.

You are missing the end bolt which keeps oil in the engine, and dirt from entering the engine. Can you find another bolt which fits the hole?

I did find a bolt for the tensioner. The gas tank is at the shop for painting (red mustang). I checked the plug and is white. The drill bit I used for increasing the size of the hole in the main jet is 1/16" (1.58 mm). When riding at low speeds or 2/4 of throttle the plug is black but at 3/4 o 4/4 of throttle the plug is white. Because I´m out of money these days (I went to the beach), I want to increase the hole´size but I am afraid the drill bit size will be 5/64" (don´t think will find an intermediate size 1/16-5/64"). Also I will cut over 27 cm of exhaust and not sure how this will affect the carb. I mean, will need to increase jet size or decrease?

Saludos Chineros

[SpudRider]

Personally, I would not drill the carburetor jets. Mikuni main jets are very inexpensive, if purchased from the following vendor.

https://www.rockymountainatvmc.com/p...uni%20n102/221



You can learn more about carburetor jets for you Zong by reading the following threads.

http://www.chinariders.net/showthread.php?t=6501
http://www.chinariders.net/showthread.php?t=6528

[Weldangrind]

Jets are even cheaper when purchased directly from China. Shipping is often free.

I drill jets occasionally, but I use a numbered drill bit set that has many sizes in between the typical 64ths.

[jct842]

1/16th is way too big for a main jet. I have drilled jets and you use a oriface drill set and a pin vice to hold the bit. I can't give exact sizes off top of my head, they are out in the garage/shop. You can solder a too big jet completely shut and start over. There are charts on the internet that give the hole size that corilates with jet sizes. John

[Weldangrind]

It's easy with Mikuni jets, because they're Metric. A 100 jet means 1.00mm, a 110 jet means 1.1mm, etc.

[hect75]

Originally Posted by Weldangrind

It's easy with Mikuni jets, because they're Metric. A 100 jet means 1.00mm, a 110 jet means 1.1mm, etc.

I went to the hardware store but did not find a metric drill bit. They have only on 64ths. I will take the mainjet this wed to some motorcycle shops and see if I find something for the carb.

Saludos Chineros

[SpudRider]

You are unlikely to find Teikei carburetor jets at any motorcycle shop. However, I suggest you do as I, and try to find some Mikuni N102/221 jets. The following thread contains all the information you need to understand carburetor jets for your Zongshen ZS200GY-2.

http://www.chinariders.net/showthread.php?t=6501

I quote from the above thread.

Zongshen 200GY-2 With Stock Muffler:

If you are using the stock muffler at sea level, the stock, size 132, Teikei main jet is probably pretty close to ideal. Begin your experiments by raising or lowering the jet needle. If the jet needle adjustments are not adequate, I suggest you experiment with the N102/221 Mikuni main jets. The stock Teikei main jet is roughly equivalent to a size 130, Mikuni main jet. Therefore, to lean out your mixture, start your experiments with a size 127.5, Mikuni main jet. To enrich your mixture, begin experimenting with a size 132.5, Mikuni main jet.

[Weldangrind]

If you were serious about drilling jets, you'd need a numbered drill bit set. It is not Metric, but conversion is easy.

Like this:

[Weldangrind]

BTW, I agree with Spud. Just buy the jets he recommends.