Reed valves

[strathroy]

Has anyone figured out what the reed valves in our engines do?

[Papermaker]

Strathroy--

I've seen them used by motorcycle and other manufacturers as part of their emission control systems.  On those bikes they lower emissions by allowing air (oxygen) to enter the exhaust.  The extra oxygen mixes with unburned hydrocarbons allowing them to burn completely.

--John

[Coconut]

Hi Strathroy,

Are you referring to the Reed Valves in the top of the cylinder head for the Secondary Air Injection system ?

Service Manual 10.147 - Secondary Air Injection :

"The secondary air injection system is an aid to reducing levels of pollutants in the exhaust gases.
It does this by introducing a small amount of air into each exhaust port as the exhaust valve opens.
The introduced air helps promote further combustion of the fuel mixture after it has left the combustion chamber.

At certain specific engine speeds above idle, ( determined by factory programming of engine management system ),
the secondary air injection control valve is opened by the ECM and allows an air feed into the secondary air system where,
each time a pair of exhaust valves open, the exhaust gases in the exhaust port create a depression which causes
reed valves in the secondary air injection system to open. 
When open, the depression in the exhaust port draws air from the control valve, through the open reed valves,
into the exhaust port.  This air promotes combustion of the exhaust gases in the ports and the header system.

At other engine speeds, the system is disabled by closing the control valve in the system."

[strathroy]

Thanks guys

[cropbiker]

And there I was thinking the reed valves meant you could play a better tune on it! 

[john348]

And there was me thinking we sudden;y had a2 stroke   

<edit>
Will have to stop writing while eating a sandwich!!!