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.

Click to expand...

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.

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.

Click to expand...

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.