Chinese Skyjet based on Honda CG125 engine

I have just bought a new Chinese motorcycle which is based on a Honda CG125. Sometimes it starts on the button, runs for about 2 kilometers then cuts out and won't start. Other times it starts and suddenly goes from
1000 rev tick over to 4000 revs and stays there until either the machine is put in gear and the clutch let out or the front hand brake is applied and the reves come down to 1000 when the brake is realeased it goes back up to 4000 revs.

Can anyone offer any advice on what is making it do this?

 

Since no-one else had the basic sense to let you know... you should put this into the forum for tech discussion of non-xj bikes.

Sorry I can't answer the question, but good luck with it.

 

My buddy bought a chinese quad, it would start and run but crap out at higher rpm, eventually it died and wouldn't start. After we got it home and had a bite to eat it started right up. Due to engine noises that he could hear, I could on occaision, he decided to purchase a replacement motor. He only replaced the motor, not the coils or tci unit, and the quad runs great. Soooo, we think the problem in this case was the pick up coil ? I've been itching to tear into the old motor to have a look, but haven't yet.

He also had a problem with idle rpm not staying put, found out they didn't put a gasket between the engine and carb. This helped a lot but didn't solve the problem

 

To be brutally honest, when you buy a chinese bike you should basically strip it down and put it together properly before you use it.

A bloke in the workshop next to me imports then and to be honest, the workmanship on them is nothing short of crap.

Cross threaded bolts, brackets welded on crooked, missing bolts and poor fitting parts.

Carbs are built and slapped on without any standard setting. Almost every bike I have helped him with, required a little tuning just to get it to run and idle.

Biggest problem is the carbs. Mixture has no standard setting and the float levels are not set to any particular height.

While they are cheap and can be fun, they seem to be built with no quality control at all.

And don't be fooled by the based on Honda engine sales gimmick. Nothing in the Honda shop will fit on there.

As for your problem, I would check around the carbs for air leaks. Sounds like it is getting too much air in there. Don't be scared to play with the mixture screw either. Most of them need to be turned out a turn or two anyway. And also check the fuel tap. You'd be surprised at the number of people who can't work out off/on/reserve from those silly chinese pictures stamped on the tap. :wink:

 

I must throw in with HG. Several buddies have made the poor choice of purchasing cheap Chinese motor vehicles and each has been a nightmare of support problems and running issues. I wouldn't touch one with a ten foot pole. I don't suppose anyone would be able to give them away either. I think you said it all in your post HG, even new one should tear it down and rebuild it to make it safe.

 

LIFAN is the company i believe you speak of here.

They are being sued by honda for patent infringement.

http://www.china.org.cn/english/BAT/42162.htm

 

82Max - The link you posted is to an article written 5 years ago and only mentions the fact that Lifan formed their own IP group and is working to develop their own technology. Can you post the link to the article about them being sued by Honda?