Norton Mk3 crankcase reed valve -June 2019

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p400

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Owner was having issues with crankcase oil blowing from primary while also weeping from various location.
I fitted a Chris Greenbacker crankcase reed valve today on a Mk3 stock Norton.
Here's photos!!

I reused the 1975 OEM breather hose and 1975 OEM clamp.

We have been unable to test for notable improvements due to weather conditions.



Norton Mk3 crankcase reed valve -June 2019
Norton Mk3 crankcase reed valve -June 2019
Norton Mk3 crankcase reed valve -June 2019
Norton Mk3 crankcase reed valve -June 2019
 
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I like the way it routes the breather line back to the tank. Where do you get one like that?
 
Considering a reed valve breather mod but they seem tricky to source in UK. Suggestions appreciated.
 
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They are an EGR valve, search on ebay for egr valve in motorcycle parts. They will come with various pipe configurations to suit your intended pipe run.
 
It is an EGR valve from a Yamaha 125 (not sure which model - some have inlet/outlet differently orientated to the one shown in this thread.)
Often available on Ebay used but working perfectly for about £10 - £15.
 
It is an EGR valve from a Yamaha 125 (not sure which model - some have inlet/outlet differently orientated to the one shown in this thread.)
Often available on Ebay used but working perfectly for about £10 - £15.
I think it's from a Yamaha majesty
 
Did this installation have any effect on the oil leakage?

Glen
It did on my Mk3, but in addition to this reed valve, I now tighten the oil filler cap extremely tight.
I use a new cap from Andover, have tried silicone oil cap gaskets and found them too thick.
Simply tighten stock cap/gasket and no leaks.
 
Hadn't thought about the cap seal importance.
Makes good sense for the MK3 with its breather system.
I wonder if the reed valve works in the normal way here with carb vacuum pulling on the topside of the reed valve?

Glen
 
Never worried about this install direction and reed config.
Found more recommendations for this install direction tho.
found somewhere on the interweb.


Image1.jpg

This breather system also includes a vented plastic small soda bottle to capture any liquid coming from the oil tank vent hose.
Catch bottle hidden in the air cleaner space after converting big Mk3 plastic airbox to K&N air filter.
I have thought about increasing the diameter of this "catch" hose to reduce back pressure, but not made chg yet.
 
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Never worried about this install direction and reed config.
Found more recommendations for this install direction tho.
found somewhere on the interweb.


View attachment 83120

This breather system also includes a vented plastic small soda bottle to capture any liquid coming from the oil tank vent hose.
Catch bottle hidden in the air cleaner space after converting big Mk3 plastic airbox to K&N air filter.
I have thought about increasing the diameter of this "catch" hose to reduce back pressure, but not made chg yet.
It only works in one direction. If you install it backwards it will block any breathing action.
 
Never worried about this install direction and reed config.
Found more recommendations for this install direction tho.
found somewhere on the interweb.


View attachment 83120

This breather system also includes a vented plastic small soda bottle to capture any liquid coming from the oil tank vent hose.
Catch bottle hidden in the air cleaner space after converting big Mk3 plastic airbox to K&N air filter.
I have thought about increasing the diameter of this "catch" hose to reduce back pressure, but not made chg yet.
I have the HNW reed valve fitted really low down in the cradle to keep it as hot as possible & avoid the build up of emulsified sludge or "snot"
IMHO the position of the valve as indicated on the HNW webpage (High up against the frame) could cause the vapour & moisture to cool; significantly & congeal in the pipe run .... and potentially block it... Well certainly with minimal running & colder climates.
 
I have the HNW reed valve fitted really low down in the cradle to keep it as hot as possible & avoid the build up of emulsified sludge or "snot"
IMHO the position of the valve as indicated on the HNW webpage (High up against the frame) could cause the vapour & moisture to cool; significantly & congeal in the pipe run .... and potentially block it... Well certainly with minimal running & colder climates.
Yes I want to mount mine as close to the case as possible. I will probably have my timing side case sent out for the anti wet sump check valve and may investigate adding a pipe nipple to the reed valve to screw directly into the case. I can also add a 90 degree elbow to the outlet side if need be. 18 years as a pipefitter will perhaps allow me to make a nice tidy installation .
 
My reed valve is mounted low as I was using the stock Mk3 airbox at first....and still is mounted low.

Mounting the reed valve high allows both hoses in/out to drain appropriate directions and stay sludge free.
 
Mine is up under the seat behind the air cleaner plate. My cNw e-starter won't allow mounting it low.
 
I have the HNW reed valve fitted really low down in the cradle to keep it as hot as possible & avoid the build up of emulsified sludge or "snot"
IMHO the position of the valve as indicated on the HNW webpage (High up against the frame) could cause the vapour & moisture to cool; significantly & congeal in the pipe run .... and potentially block it... Well certainly with minimal running & colder climates.
+1

The valve needs to be close or attached to the engine for best efficiency and avoid that white sludge.

The Comnoz / NYC sump breather is pricey, but undoubtedly the best.
 
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