Low tech reed valve idea...

ferball

ferball

New Member
I know one of the holy grails that some here are looking for is a cheap reed valve for this high tech, high performance engine....

So I had a thought yesterday, why not use an inline check valve on the intake between the carb and the engine. There are plenty of posts of people lengthening their intake or altering the angle with cheap tubing/hose. So why not add a check valve in the same manner? Has any one tried this? I was thinking that you would need to use a swing type valve as opposed to the spring type, but I also found cheap 1/2 diameter vacuum check valves that would probably work. My concern is that the constant open close would eventually cause the valve to fail, and that would get sucked into the engine, so I was looking for an all plastic valve that would minimize damage in such an event.... Has any one tried this? Can you gear heads tell me why a reed only would work and not a check valve?
 
I like your idea.
I am in the process of making one from a steel chainsaw reed valve (just the flapper) and bolting together pieces of aluminum stock to form a housing.
Fairracing posted pics of the reed valve he built.
Can you post a pic of the 1/2" vacuum check valve? That sounds much easier than carving a housing from aluminum.
 
Here is the Home Depot link Check Valve

But if you do a google search, you can find some different options. My concern with the brass swing valve is that if/when it falls apart from the constant abuse, all that stuff ends up getting sucked into your engine.
 
I don't think that thing will work for this application. Seems like it won't have near the flexibility you're looking for out of a reed intake. After all, the check valve will have a tendency to just open up all the way under almost any throttle input. Reeds move open progressively allowing for smooth airflow, and flex back partially with the slightest of reductions in throttle twist. At best, I think you'd notice little difference, at worst, it will screw up your venturi so much that you'll have noticeable power loss..

Of course, what do I know? Try it and prove me wrong.
 
If I can get my hands on a plastic check valve I will try it, that way if it implodes the plastic won't tear up the engine to bad....
 
I've actually taken one of those check valves apart and I can tell you it won't work. For one the valve is very restrictive inside, the airflow would have to make two 90º turns inside and the main problem is the actual check flapper is way too heavy to be actuated like a reed valve needs to be. There's no way a 2 oz. piece of brass is going to move that quickly.

What someone needs to come up with is a bolt on reed box (something similar to a Puch reed) that just takes the place of the intake. It should be pretty simple, just an an aluminum box that bolts onto the jug and the cover has a tube to mount the carb onto.
 
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