Reed valves

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crusadersports

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Hello Gents,

I always thought a reed valve was something to do with Yamaha 2 strokes...

Yet reading various threads suggests they are something to do with reducing crankcase pressure and combating oil leaks. Can anybody enlighten me? Do they work- should I buy one?
 
Uh uh crusader you jumped in too deep to quick for a straight answer on this pressure subject. First you must get up to speed on the oil threads before you might even understand what you just asked so seemingly innocently.
 
"The Mystery Man got nervous
An' he fidget around a bit
He reached in the pocket of his Mystery Robe
An' he whipped out a reed valve kit
Now, I thought it was a razor
An' a can of foamin' goo
But he told me right then when the top popped open
There was nothin' his box won't do
With the oil of Afro-dytee
An' the dust of the Grand Wazoo
He said:
"You might not believe this, little fella, but it'll cure your Asthma too!"


There are two kinds of Nortons out there...those that have breather valves and those that will! Sort of like adding fiber to your diet, the exact benefits can be argued, but everybody seems to agree it is a good idea.

Here is some reading for you:

inline-breather-valves-revisited-t7637.html?hilit=breather
breather-valve-problem-t7562.html?hilit=breather
xs650-breather-exposed-t7345.html?hilit=breather
one-way-breather-valve-differences-t5929.html?hilit=breather
xs650-mount-near-tank-breather-t5866.html?hilit=breather
crank-case-breather-t3680.html?hilit=breather

I have the XS650 valve on my 750. My current project is getting the CNW/Jim Comstock valve.

Russ
 
rvich said:
"The Mystery Man got nervous
An' he fidget around a bit
He reached in the pocket of his Mystery Robe
An' he whipped out a reed valve kit
Now, I thought it was a razor
An' a can of foamin' goo
But he told me right then when the top popped open
There was nothin' his box won't do
With the oil of Afro-dytee
An' the dust of the Grand Wazoo
He said:
"You might not believe this, little fella, but it'll cure your Asthma too!"



...
Russ
Click to expand...
Zappa :lol: :lol: 8)
 
Crusadersports,

There are many, many posts here explaining the reasons for a reed valve crankcase breather, how well they work, where to mount them and where to get them.
 
G'day crusader,
You are partly right, they are something to do with Yamaha 2 strokes, and any other post, early 70s 2 stroke.
They are a one way valve, flapper valve, for want of a better explanation, made from some sort of "modern nylon" or such.
Simply, they are a flat piece of "nylon" fixed at one end to a solid (alloy) block and over lapping, that can inturn be fixed to something else,
(in the case of a Yamaha, the barrel) to allow something to go in (fuel mixture), but not get pushed back out by the rotation of the engine.
The "flat pieces of nylon" are refered to as "Reeds" hence a Reed Valve.
They are a light and simple way to allow excessive Crankcase pressure to escape your Norton engine, thus helping to
reduce oil leaks.
That's my simple explanation.
Now I don't profess to know what they are made of, nore do I profess to be an expert.
Some one here will.
Hope this helps.
AC.
P.S. I had a pre reed valve 360 Yammy that would run backwoods. Interesting to say the least.
 
One way breather valves work well on Commandos (and big singles too). They reduce crankcase pressure which causes oil leaks and which can blow drive side crankcase seals. The after-market reed valve breather for the Yamaha XS650 does the job and is quite cheap. Just buy one and if you need some tips on plumbing it in, ask the forum. I got mine from a shop in Germany (cheaper postage than from the US), See here: http://shop.xs650shop.de/front_content.php?idcat=3

Dave
 
I just installed one of Jim's new valves. I had been using an automotive AV reed valve in the breather line off the timing case for years. I've had a leak at the main seal that amounted to less than a teaspoonful per 100 miles. I'm running a dry belt so it created a mess. The new valve cured the leak. I capped the breather line at the timing case but haven't sealed the holes between the crankcase and the timing case yet. I understand the volume of the timing case buffers the pressure pulses that make the reed valve work, so it'll work even better if the 'breathing holes' to the timing case are closed up. If I can seal those holes without splitting the cases I'll probably do that this winter. But, as it is I'm happy it's one more base that's covered so I can fret about other things.
 
Bob,
You can just machine some aluminum plugs with a little bit of taper to them. Tap them into the holes with a bit of JB weld on them and they will stay put. The messy part is drilling the new oil return hole next to the oil pump. If you create a paper mask to catch the chips it can be drilled on the bike. Jim
 
on my mk3 i cut the breather tube flush then put a bolt in the breather tube and filled it with jb weld to seal it then I screwed it back in. That way it's not a permanent seal and can revert to stock if needed.
 
pelican said:
on my mk3 i cut the breather tube flush then put a bolt in the breather tube and filled it with jb weld to seal it then I screwed it back in. That way it's not a permanent seal and can revert to stock if needed.
Click to expand...

Bob was refering to the holes between the crankcase and the timing chain area. If you plug those holes and drill a new small oil return hole the reed breather will work more effeciantly. Jim
 
The photo below shows all I believe! Photo courtesy of clever bike builder Jeandr!
Reed valves

Also asking, what size is the new bottom hole size?

Foxy
 
Hi,

Looking at the picture that shows all the holes that need to be plugged, there is one that we dont consider when doing the breather modification. Its the forward hole that is there to run the leads into the ignition cavity. This is not part of the pressurized timing chest and if you plug that hole, then I am not sure how you would run the wires to hook up the ignition.


Matt / Colorado Norton Works
 
Jean obviously had an alternate ignition in mind. I think he was doing a crank trigger. Jim
 
pelican said:
on my mk3 i cut the breather tube flush then put a bolt in the breather tube and filled it with jb weld to seal it then I screwed it back in. That way it's not a permanent seal and can revert to stock if needed.
Click to expand...

That's basically what I did too. I can't wait till some Norton wonk starts picking my bike apart and comes across the blocked breather... :D
 
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