Zongshen 161FMJ 150cc carb jets

[Fuzzynights]

Hi guys,

Because my bike isn't running so fine on half throttle, i checked the carb today. I have to turn the airscrew several rounds open to get it to work at its best.

I looked at the jets:

Main jet: 125KB
Pilot jet: K40

The motor is a Zongshen 161FMJ 150CC.
Carb is a Sheng Wey.

Anyone has suggestions ? What do you think about the jet sizes ?

[Weldangrind]

The air screw (or pilot screw) should only affect idle and the transition off of idle. If your bike does not run well at half throttle, first try dropping the clip another notch on the jet needle and see if there is an improvement.

[humanbeing]

De facto carb for chinese 150 is PZ27 http://www.dekni.com/production/produ_moto2.php
Stock carb in Loncin engine that made by above Keihin jv http://item.taobao.com/item.htm?id=1902950047
Engine is same bore & stroke as GL PRO (Indonesian model) / Good old ancestor http://page12.auctions.yahoo.co.jp/jp/auction/p248320666 :lol:
Picture will talks what a REAL thingy should looks like
http://a.imageshack.us/img844/8862/001ky.gif
http://a.imageshack.us/img29/6233/002hp.gif

[Fuzzynights]

Whoops, got a problem here. :(
After opening and cleaning the carb, i put everything back like it was, but when starting the engine sputters and i have to turn my idle screw to its highest position to avoid the motor to shuts off.

the spark plug is really black and wet, and i have to remove the air filter to keep the engine running...

Suggestions anyone ? I cleaned the carb with pressured air, and cleaned both jets througly. I have no clue what's going on now :evil:

greetz,

Fred

[FastDoc]

Float level may be wrong or stuck on.

[Fuzzynights]

thanks, will check this in tommorow morning; I remember i stuck my air-pressure pistol under the floats; so maybe i bent it a little bit.

http://www.allthingsmoto.com/forums/f-15/how-set-your-motorcycle-carburetor-float-level-more-commentary-13608/

[humanbeing]

The chinese (http://translate.google.com/translate?sl=auto&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.motorfans.com.cn%2Fbbs%2Ft_4614 89_1.htm) thread about these type of carb

[Fuzzynights]

Opened the carb today and tried to set the float level to its good position. now i can start the engine and it runs nice, but the spark is a little black.
But as soon as i mount the airfilter or put some kind of cotton fabric before the inlet, the engine shuts down immediately :?

[humanbeing]

Valve clearence OK? http://www.kiwibiker.co.nz/forums/showthread.php/57500