rjd-200x sputtering
 

My rjd-200x does fine when I'm just cruising but when I give it alot of gas it starts to sputter.What do you think the problem is?

My guess would be not enough fuel to the carb. My kids 125's did this as well. I moved the needle in the carb up a notch and they run great now. There's a short tutorial in the content section. Hope this helps.

http://www.chinariders.net/modules.p...showpage&pid=3

sputtering
 

I tried all of the slots but it still sputterd so I put it back to the stock position and went for a ride.It backfired and sputterd when i was going on bumpy trails but when I went down a patch of pavement where it was smooth it ran fine.Does anybody know what the problem could be?

What's the plug colour like? Is it running rich/lean?

Have you checked valve clearances?

How about the air filter, it may be dirty.

spark plug
 

I cheked the spark plug and it is a whitish gray color so I guess it is running lean.How do you check the valve clearance?I dont think the air filter is dirty because I have not rode it very much.

Re: rjd-200x sputtering
 

same bike, same problem... You can adjust fuel screw on lower side of carb float bowl, this will help with idle to 1/4 throttle. Also, open top of carb, pull out slide, move clip on jet needle down one position to richen fuel mix for 1/4 to half throttle... If you lose the clip dont worry because you can get them at auto parts stores like napa, hope that helps you out. It cured my problem. If that doesnt fix it, you may need a larger main jet or needle jet, etc.

Hawk

The clip move should help some.
I experienced a similar problem when putting on a freeer flowing air filter on my GY-5 200.
There is also a fuel screw on my carb. In most cases people don't need to mess with them. (Although RPM said he does adjust them when setting up new bikes for customers).
Here is a picture of it on a Lifan:
http://www.chinariders.net/gallery2/...g2_itemId=1092
(I don't know what engine you have so the screw may be in a different location)
To get it to run richer start backing out the screw. (counter-clockwise if you are looking directly at the head). If there isn't a factory marker line then you may want to use a sharpie and mark the original setting.
Start backing it out about a quarter turn at a time. Go ride around the block and then adjust again if needed. I had to go about 1and a quarter turns out to smooth out the sputtering.

same problem my mech says its my crappy ass flyweel. Never buying a jianshe again. Thats why i bought myself a nice cr125

Dlunt, do you have another picture of that carb screw. My Lifan 100 sputters a little when taking off, stops once it is revving. I think that adjustment might work for me. I just can't tell, from the photo, which screw it is.
Thanks in advance.

I don't have another picture but If you stand on the left side of your bike (where the shifter is :wink: ) and look behind the engine at the carb, the screw is on on the front side bottom. Just use a sharpy and mark the starting point. Unscrew a quarter turn and try it.

The clip change will help more than anything if you still have the stock air filter.

It is just as you start to open the throttle. I think the carb ajustment will work. I found the screw you are talking about, will try it tomorow. Thanks again.