wet sump solution 2

Matt is right... HIS sump mounted reed valve does that....

MY dual reed valves are NOT sump mounted valves. One is mounted on the back side of the timing chest , and my other is mounted on the end of the camshaft because early bikes had a hollow cam and a port on the primary side of the crankcase half at the end of the cam..


Here's where one of my breather's is mounted... on the camshaft port


Here's where my other breather is mounted on the timing side



Here's what my case looks like behind the timing cover
green arrow - breather reed hole
red arrows - 3/8" holes into crancase to allow air to move easily way above any potential oil height in the sump
yellow arrow- 1/4" hole drilled to lower the oil level in the timing chest so the breather blows mostly air


I did these modifications before the sump breather that Jim Comstock developed was invented... and you should just buy one rather than copy my madness...

o0norton0o said:

Matt is right... HIS sump mounted reed valve does that....

MY dual reed valves are NOT sump mounted valves. One is mounted on the back side of the timing chest , and my other is mounted on the end of the camshaft because early bikes had a hollow cam and a port on the primary side of the crankcase half at the end of the cam..


Here's where one of my breather's is mounted... on the camshaft port
View attachment 125109

Here's where my other breather is mounted on the timing side

View attachment 125110

Here's what my case looks like behind the timing cover
green arrow - breather reed hole
red arrows - 3/8" holes into crancase to allow air to move easily way above any potential oil height in the sump
yellow arrow- 1/4" hole drilled to lower the oil level in the timing chest so the breather blows mostly air
View attachment 125111

I did these modifications before the sump breather that Jim Comstock developed was invented... and you should just buy one rather than copy my madness...

Click to expand...

Thanks for the explanation and photos! Very helpful.

swolh said:

Thanks. I may have misunderstood Matt at Colorado Norton Works, but I thought he told me that the reed valve breather returns oil to the tank in addition to the oil pump return line - that it adds a second way oil can return to the tank. I understood him to say that adding a reed valve breather is now the only thing they do to manage wet-sumping. Put another way, that a reed valve breather will return oil to the tank so quickly that it doesn't matter how much oil may have collected in the sump when the bike is sitting, and when it's running, if the oil pump isn't keeping up returning oil to the tank, the reed valve breather picks up the slack. Again, I may have misunderstood him.

Click to expand...

I will disagree with what you said CNW said....if the engine is fully wet sumped, ie ALL oil from the tank is now in the sump, there will be no oil pressure at startup until enough oil has made it back to tank, and worked its way back down the feed line to the pump. This may take several seconds after engine starts up.

My soluton fully prevents wetsumping by closing a tap on feed line btwn rides...and a microswitch in the tap to defeat igitiin saves any potential forgetfulness on my part.

Tornado said:

I will disagree with what you said CNW said....if the engine is fully wet sumped, ie ALL oil from the tank is now in the sump, there will be no oil pressure at startup until enough oil has made it back to tank, and worked its way back down the feed line to the pump. This may take several seconds after engine starts up.

My soluton fully prevents wetsumping by closing a tap on feed line btwn rides...and a microswitch in the tap to defeat igitiin saves any potential forgetfulness on my part.

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I don't disagree - That's why I also installed a Feked anti-wet sumping valve (tap) with the electrical cut out switch to insure that if I forget to open the valve the bike won't start. I have both the Feked and the CNW reed breather. But I defer to Mike at CNW on the subject. I don't recall asking hm what happens if all the oil has seeped out of the tank and into the sump.

The weird thing is that, from what some folks have posted, it seems like some of these bikes wet-sump like crazy (your example of a bike sitting long enough to empty the tank completely - the dipstick level on mine dropped around 1/8 inch every few days even after new MKII timing cover and pump with the AMR modification), while others seem to wet sump minimally or maybe not at all. Maybe that's atrributable to the different deisgns of the crankcases and location of the holes in the cases into the timing cover area. That's above my pay grade.

swolh said:

I don't disagree - That's why I also installed a Feked anti-wet sumping valve (tap) with the electrical cut out switch to insure that if I forget to open the valve the bike won't start. I have both the Feked and the CNW reed breather. But I defer to Mike at CNW on the subject. I don't recall asking hm what happens if all the oil has seeped out of the tank and into the sump.

The weird thing is that, from what some folks have posted, it seems like some of these bikes wet-sump like crazy (your example of a bike sitting long enough to empty the tank completely - the dipstick level on mine dropped around 1/8 inch every few days even after new MKII timing cover and pump with the AMR modificatio), while others seem to wet sump minimally or maybe not at all. Maybe that's atrributable to the different deisgns of the crankcases and location of the holes in the cases into the timing cover area. That's above my pay grade.

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My 850 will loose all tank oil, level below the pickup screen, within 2 to 3 wks sitting...before I fitted the tap amd microswitch. Cheap (esp if you cobble it together yourself like I did..$15 & an hour or two work), easy, sorts the problem entirely.

I run the same crank case the way it come from the factory without any holes drilled or modified, my oil pump is the original oil pump that has never been touched/pulled apart in the 50 years of ownership, had the seal replaced every time the motor has had bottom end work and reprimed after any work done, I don't run any oil pressure gauge or oil light, and I never worry about the oil pump doing its job, but will check the oil return in the tank every so often, I just start it and ride it without even thinking about the oil pump and as I say it only wet sumps if I let it sit for over 4 month, but once I forgot to turn off my fuel taps and one float stuck, not knowing this I fired up the bike and oil and fuel pumped out of my breather hose and filled up my catch bottle, that was about 35 years ago, I now run a yammy reed valve on my breather hose beside the crank where the breather comes out of the crank case, that was the first time it wet sumped and has only wet sump 2 x after that.
My Norton has been sitting now for 5 1/2 months since my accident still have oil in the oil tank but its down from its normal level so the rest be in the crank, my round oil tank only holds 2 1/2 ltr of oil, I also run a Lochead oil cooler all year round and also mix STP in my oil since 1982.
My 850 has been a everyday ride most of its life only semi retired in 2013 but ridden regularly when I brought a new Thruxton, has well over 160k miles on it and average between 6k to 10k miles a year when it was an everyday rider, if it did wet sump from sitting to long I just drain the oil but as I said have only done that3 times in 50 years, no big deal for me.

Ashley