Emissions control

[FastDoc]

I have an '08 HSUN/Lifan GY 200 and an '08 QLink XF 200.

Both have some weird plumbing on the cylinder head with some sort of a valve and metal lines. What's that all about, and is it hurting my performance (such as it is :roll: ), and can it be removed?

TIA,

Bill The Fast Doc

[SpudRider]

Originally Posted by FastDoc

I have an '08 HSUN/Lifan GY 200 and an '08 QLink XF 200.

Both have some weird plumbing on the cylinder head with some sort of a valve and metal lines. What's that all about, and is it hurting my performance (such as it is :roll: ), and can it be removed?

TIA,

Bill The Fast Doc

Hi, Doc. China Riders member Forchetto has posted a lot of great information on the Qlink at the mychinamoto.com forums. I am sure he will soon reply to you here, as well.

Spud

[forchetto]

On the Qlink at least, the items you can see attached to the cylinder head are the air injection gear for the SAI (Secondary Air Injection) system.

This System comprises a vacuum valve, a one-way reed valve block, and an oxidation catalyser element. This last item is inserted into the exhaust silencer during manufacture.

The idea is that fresh air is injected by the reed one-way valve on positive exhaust pulses inside the exhaust system. This air helps to burn off any hydrocarbons left after the combustion process and together with the catalyser converts CO into CO2. The vacuum valve is meant to shut off the air supply during high deceleration rates (and therefore a high vacuum) to stop popping and banging in the silencer.

This system is a bit rough and ready and nowhere as sophisticated as the latest 3-way catalysers with Lambda probes and electronic management found on the latest bikes and cars but is the best and cheapest way for the Chinese to comply with Euro emissions laws.

They also under-jet the engines for the leanest mixtures possible regardless of what it does for driveability and performance. You'll find that a lot of the running problems with lots of Chinese bikes can be solved by jetting up, both the slow-running and main jets, raising slide needles, or at least by tweaking the mixture screw a bit richer.

The downsides are a loss of performance mainly due to the small catalyser element that literally blocks the exhaust pipe, (losing something like 2 HP on the XF200), a high downpipe temperature due to the combustion of waste gases that takes place there, (this extra heat makes the catalyser work better though), and lastly there are some that believe that the constant blasting of the hot exhaust valve with cold air doesn't do it any favours.

Although the systems work well enough to pass homologation tests, in my experience the Chinese components themselves, like under-tempered reeds, fast perishing hoses, etc are badly made and sometimes badly assembled and not very durable. But that's OK, once the tests have been passed, the Chinese dont give a fuck...

This is a diagram of the system attached to the cylinder head:



Some models do away with the vacuum valve control refinement and just stick the one-way reed valve directly on to the downpipe just after it exits the exhaust port:



This is the catalyser insert inside the silencer:



Other makes put the catalyser element in a widened portion of the downpipe like this:

[SpudRider]

Forchetto,

Thank you for another superb post! Your knowledge of the Qlink/Qingqi motorcycle is impressive, and I have personally learned a great deal from you. Once again, thank you for all your frequent, excellent contributions to these forums.

Spud

[forchetto]

Thanks spud. I've done a lot of research for that bike, had to, as the factory hasn't issued a service manual to anybody as they don't have one in English.

I have managed to get by using the Suzuki DR200 one, but there are many differences in detail.

Qingqi have a manufacturing partner in Brazil called STX Sundown that produces Qingqi bikes for the South American market and they have produced a truly magnificent service or workshop manual for the GY bikes, both the cross and the supermoto types. Unfortunately it's in Portuguese, but being Spanish I can manage to understand most of what's it's written in Portuguese.

This will enable me to become even more pedantic and bore a greater number of people...

Thanks to LuisCarlos for providing it to mychinamoto.com and Crazycarl has put it on the forum as a sticky. Even if you can't understand the words, there are nearly 500 pages, good photos, lots of data and even circuit diagrams in full colour:

http://www.mychinamoto.com/forums/showthread.php?t=725

[SpudRider]

Originally Posted by forchetto

...This will enable me to become even more pedantic and bore a greater number of people... ...

Not true! You posts are a wonderful resource to all Qlink/Qingqi owners, and I always learn much by reading them.

Originally Posted by forchetto

...Thanks to LuisCarlos for providing it to mychinamoto.com and Crazycarl has put it on the forum as a sticky. Even if you can't understand the words, there are nearly 500 pages, good photos, lots of data and even circuit diagrams in full colour:

http://www.mychinamoto.com/forums/showthread.php?t=725

Thank you for notifying us of this superb resource! I am going to visit Crazy Carl's web site and check it out, immediately!

Spud