wet sump solution 2

o0norton0o · Jun 7, 2026

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...

swolh · Jun 7, 2026

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...

Thanks for the explanation and photos! Very helpful.

Tornado · Jun 7, 2026

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.

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.

swolh · Jun 7, 2026

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.

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.

Tornado · Jun 7, 2026

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.

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.

ashman · Jun 7, 2026

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

MexicoMike · Jun 8, 2026

FWIW, back in the day my '71 Commando regularly sat over the winter for 2-3 months and in the spring I just re-connected the battery and kicked the bike to life. I never heard of wet sumping, never checked to see if oil was flowing into the tank, never thought about oil pressure.

I will admit that nowadays I do look in the tank after layup and if the oil level is below the feed line, I drain oil/add it back to the tank. Frankly, I don't know why I do this now; I never did it back then and I put a bit over 70,000 miles on that Commando. Must be the bad influence of the internet!

swolh · Jun 8, 2026

MexicoMike said:
FWIW, back in the day my '71 Commando regularly sat over the winter for 2-3 months and in the spring I just re-connected the battery and kicked the bike to life. I never heard of wet sumping, never checked to see if oil was flowing into the tank, never thought about oil pressure.

I will admit that nowadays I do look in the tank after layup and if the oil level is below the feed line, I drain oil/add it back to the tank. Frankly, I don't know why I do this now; I never did it back then and I put a bit over 70,000 miles on that Commando. Must be the bad influence of the internet!

If you've started the bike when the oil level in the tank is low, but not below the feed line, it's possible that excess pressure from the oil that did seep into the sump has blown your primary (left) side main crankshaft seal. The way to check is to see how much oil is in the primary case. It should have 200cc. (unless you've replace your primary chain with a notched belt). There's a small bolt/plug in bottom center of the primary cover. If you take that out and more than a trickle of oil comes out of the Primary, you've probably got a blown left side crankshaft oil seal caused by excess pressure in the crankcase from running it with too much oil in the sump. (Some folks report that the excess pressure didn't blow the main seal, but forced engine oil past the threads of the stud that holds the alternator into the primary.)

Ron L · Jun 8, 2026

swolh said:
I've read zillions of posts about anti-wet sumping and researched it a lot. Mine is a 1973 750 Roadster (which has a '72 Combat crankcase from the factory - apparently they had the Combat cases left over and used them on '73 Roadsters).

All 1973 750 (MkV) used the same cases as the 1972. Front sump and rear crankcase vent.

jseng1 · Jun 9, 2026

The only problem I had with wetsumping was long ago when I went to start my bike after winter storage. I was in a hurry when I checked the oil level and it was way down so I filled the oil tank and started it. Then the oil in the sump overflowed the oil tank to the point where it blew oil out the oil tank vent and all over my rear tire. I'll never make that mistake again. If the tank is empty - Just add a cup or so of oil and recheck the level after warmup.

swolh · Jun 24, 2026

FEKED FOLLOW UP

I ordered, received and installed the Feked anti-wet sumping device. It is two parts wedded together: a mechanical ball valve (tap body) that closes and opens the flow of oil from the tank to the engine, and an electrical cut out switch that disconnects electricity to the engine so it will not start unless the oil tap is open. It installs in the oil hose supply line to the engine.

The mechanical ball valve (tap) was defective.

After installing it, I accidentally slightly over filled the tank. So I figured, with the Feked ball valve closed, I'd drain the excess by removing the hose from the engine side of the Feked ball valve and slide a longer hose on it that routed the excess oil into a can. No mess.

But when I pulled off the engine side of the ball valve (tap), it was drip, drip, dripping oil. The ball valve (tap) was not completely shutting off the oil!

I sent Feked a short video of this, and they first replied that the handle was at around 70 degrees, not at 90 degrees, from the body of the valve unit, and it should be 90 degrees to completely shut off the oil flow (implying reasonably that I had simply failed to completely turn the handle to full off position). Here's the rub: When it arrived, I noticed that the handle would not move beyond around 70 degrees. I thought that was odd, but assumed that was just how it was designed.

In several emails with the Feked people (details omitted here for brevity), they (again reasonably) suggested that some debris might have flowed into the ball valve and was blocking it from closing all the way. I've previously thoroughly cleaned the oil tank and hoses and the bike has fresh oil, so I thought that was highly unlikely - but I disassembled the unit to check. It was clean. No foreign matter obstructing it.

Disassembly is unscrewing the two brass ends that the hoses go on, then unscrewing the removable end of the tap body itself. That end has the tapered nylon seat that fits the curve of the ball and seals against the ball when the ball is in the closed position. With that end removed that ball handle moved freely and easily the full 90 degree range. But as I screwed that end back on and it was finger tight (not wrenched) the handle stopped moving 90 degrees and got stuck at 70 degrees. The nylon seat was catching on the edge of the opening in the ball as the ball rotated to be fully closed. Defective ball valve (tap) unit.

I sent pictures of this to Feked, and offered to do a quick zoom video call to show them. They told me they could not do zoom (which is weird for anyone with an internet connection), but they'd reviewd my "case" and would post (aka ship) a new ball valve (tap) unit. That was last Friday. It's now Wednesday, and despite sending them follow up emails, they've gone radio silent and I've received no word from them (or royalmail.com) when this will ship. Feked doesn't manufacture the ball valve unit. But they're responsible to their customer for a defect in it, and their supplier is responsible to them. It is now 9 days since I first emailed them to notify them of this product failure, and I have no word of when the promised replacement unit will ship.

My conclusion is that the Feked unit itself is a good design, but the company is not responsive if there's a problem. Because of this, I would steer people away from Feked and go with one of the other options for a mechanical oil shut off valve coupled with an electrical cut out switch (links earlier in this thread). It is worth noting that had Inot accidentally slightly over filled the tank, I would not have pulled the engine side hose off to see it drip, drip, dripping - and the bike would have continued to wet sump (perhaps mor slowly).

For what it's worth, the mechanical ball valve (tap) unit itself is a 3/8 inch DN10 that is very common, inexpensive and easy to source. Feked has replaced the handle with one that will also actuate the electrical switch, and they've added that electrical switch (mounted to the ball valve unit as a collar that slides over it).

Onder · Jun 24, 2026

My 74 850 sumps quickly. A few years ago I put in a new AN pump. No change. It has the Comstock sump breather.
This will puke out the sump quickly but if the bike has sat I put a torch down into the oil tank and check to see if I can spot the oil level below the pickup screen. If so the little drain plug in the crankcase gets pulled and oil that issues forth placed back in the tank and the bike fired up.
It isn't worth the worry of having some sort of anti drain tap installed. Anti Drain Device Fear mongering on this list has done its job!

ashman · Jun 24, 2026

It's been 7 months since my Norton has fired up since my accident, most of the oil in the tanks has filled the crank and keeping everything nice and lubed, cam, lifters and bearings, when it's time to fire it up again after recovery I just pull the drain plug and drain the access oil out and everything be nice and lube for a start after putting the oil back in the tank and add some fresh fuel, only takes a few minutes to drain the oil, no shut off valve for me, shut off valves are for lazy people who think it's so hard to undo a drain plug, even with one leg it's not a hard task.
But then my old Norton only wet sump if it has sat for over 4 months, this is the longest time it has sat of no fault of my own and everything is covered in oil down below.
Drain the oil while you check everything else on the bike before a ride, check the tyres/pressures, check if battery is fully charged, chain adjustment/lubed, brakes fluid/rear brake adjustment, the usual things you should check before any day out on the bike, the oil be fully drained before you go through the check list, unless you don't do that at all.

Ashley

MexicoMike · Jun 24, 2026

It's funny, back in the day we typically checked tire pressure and oil level very frequently. Nowadays it seems folks seldom check it at all.
Recently on another website, an owner of a new bike complained that his engine had siezed and that upon checking the dealer found no oil in the engine. The bike had had its first service some months earlier. When asked by the dealer when he had last checked the oil level his response was that he never checked it, the oil change wasn't due for another several hundred miles. This despite the fact that the owners manual said to check the oil at each gas fillup...

Further funny... few years ago I attempted to check the oil level on our '19 Mini Cooper and discovered there's no physical way to do it! But there is a warning light (hopefully) if the level drops too low.

DennisMo · Jun 24, 2026

I also have a Feked and it has worked fine. Thanks for telling us about this defect.

grandpaul · Jun 24, 2026

I'll spare everyone the back-and-forth, mind-numbing explanations and "yours is cr@p, mine's the best", and cut right down to it:

I tried a ball valve, immediately realized I could forget.

I didn't want an electrical gizmo.

I tried the in-line ball with spring, it was cr@p from day 1 and leaked down.

Since I figured out these reeds, I have NEVER had a wet sump issue on 4 personal Commandos that I installed them on.

I have sold more than 20 of them, with ZERO negative feedback (as it should be, they are fool-proof).

No additional drilling or modifying, ZERO.

They work perfectly, don't blow out any seals, and don't "leak back" since they are not in the feed line.

I'm NOT saying they are "the best" solution. I AM saying they've worked PERFECTLY for me.

At $25, there is no downside.

swolh · Jun 24, 2026

DennisMo said:
I also have a Feked and it has worked fine. Thanks for telling us about this defect.

grandpaul said:
I tried a ball valve, immediately realized I could forget.

The whole point of the Feked and similar designs that integrate an electric cut off switch with the ball valve is that you don't have remember to open the valve - the engine won't start until you open the valve, which allows electricity to the coil. Magnetos are wired differently from coil ignitions, but to the same effect of electrically preventing the engine from starting when the valve is closed. So no risk of forgetting to open the ball valve and starting the engine.

grandpaul · Jun 24, 2026

swolh said:
The whole point of the Feked and similar designs that integrate an electric cut off switch with the ball valve is that you don't have remember to open the valve - the engine won't start until you open the valve, which allows electricity to the coil. Magnetos are wired differently from coil ignitions, but to the same effect of electrically preventing the engine from starting when the valve is closed. So no risk of forgetting to open the ball valve and starting the engine.

You didn't see my next comment after the ball valve line?

Tornado · Jun 24, 2026

swolh said:
FEKED FOLLOW UP

I ordered, received and installed the Feked anti-wet sumping device. It is two parts wedded together: a mechanical ball valve (tap body) that closes and opens the flow of oil from the tank to the engine, and an electrical cut out switch that disconnects electricity to the engine so it will not start unless the oil tap is open. It installs in the oil hose supply line to the engine.

The mechanical ball valve (tap) was defective.

After installing it, I accidentally slightly over filled the tank. So I figured, with the Feked ball valve closed, I'd drain the excess by removing the hose from the engine side of the Feked ball valve and slide a longer hose on it that routed the excess oil into a can. No mess.

But when I pulled off the engine side of the ball valve (tap), it was drip, drip, dripping oil. The ball valve (tap) was not completely shutting off the oil!

I sent Feked a short video of this, and they first replied that the handle was at around 70 degrees, not at 90 degrees, from the body of the valve unit, and it should be 90 degrees to completely shut off the oil flow (implying reasonably that I had simply failed to completely turn the handle to full off position). Here's the rub: When it arrived, I noticed that the handle would not move beyond around 70 degrees. I thought that was odd, but assumed that was just how it was designed.View attachment 125317

In several emails with the Feked people (details omitted here for brevity), they (again reasonably) suggested that some debris might have flowed into the ball valve and was blocking it from closing all the way. I've previously thoroughly cleaned the oil tank and hoses and the bike has fresh oil, so I thought that was highly unlikely - but I disassembled the unit to check. It was clean. No foreign matter obstructing it.

Disassembly is unscrewing the two brass ends that the hoses go on, then unscrewing the removable end of the tap body itself. That end has the tapered nylon seat that fits the curve of the ball and seals against the ball when the ball is in the closed position. With that end removed that ball handle moved freely and easily the full 90 degree range. But as I screwed that end back on and it was finger tight (not wrenched) the handle stopped moving 90 degrees and got stuck at 70 degrees. The nylon seat was catching on the edge of the opening in the ball as the ball rotated to be fully closed. Defective ball valve (tap) unit.
View attachment 125318 View attachment 125319
I sent pictures of this to Feked, and offered to do a quick zoom video call to show them. They told me they could not do zoom (which is weird for anyone with an internet connection), but they'd reviewd my "case" and would post (aka ship) a new ball valve (tap) unit. That was last Friday. It's now Wednesday, and despite sending them follow up emails, they've gone radio silent and I've received no word from them (or royalmail.com) when this will ship. Feked doesn't manufacture the ball valve unit. But they're responsible to their customer for a defect in it, and their supplier is responsible to them. It is now 9 days since I first emailed them to notify them of this product failure, and I have no word of when the promised replacement unit will ship.

My conclusion is that the Feked unit itself is a good design, but the company is not responsive if there's a problem. Because of this, I would steer people away from Feked and go with one of the other options for a mechanical oil shut off valve coupled with an electrical cut out switch (links earlier in this thread). It is worth noting that had Inot accidentally slightly over filled the tank, I would not have pulled the engine side hose off to see it drip, drip, dripping - and the bike would have continued to wet sump (perhaps mor slowly).

For what it's worth, the mechanical ball valve (tap) unit itself is a 3/8 inch DN10 that is very common, inexpensive and easy to source. Feked has replaced the handle with one that will also actuate the electrical switch, and they've added that electrical switch (mounted to the ball valve unit as a collar that slides over it).

View attachment 125317
View attachment 125318 View attachment 125319

Not sure how you reckon Feked are not being responsive...seems they have worked a lot of contact back and forth with you and habe agreed to send a replacememt unit. 9+ days to ship from UK is not out of bounds these days, esp if they are using a lower price point shipping option for a warranty replacement. Poor response on subsequent communications may be due to any number of issues (perhaps the individuals is on summer va-ka etc). Cut them some slack.

Seems like you ball valve may just need a litte deburring or shaping of the seal area to get it fully closing.

Dedubyah · Jun 24, 2026

swolh said:
The whole point of the Feked and similar designs that integrate an electric cut off switch with the ball valve is that you don't have remember to open the valve - the engine won't start until you open the valve, which allows electricity to the coil. Magnetos are wired differently from coil ignitions, but to the same effect of electrically preventing the engine from starting when the valve is closed. So no risk of forgetting to open the ball valve and starting the engine.

Well, you kind of do have to remember, otherwise you can kick your heart out, it's not starting...hmmmm, did I screw up my starting proceedure? How long do I have to kick it now I forgot to turn it on? Ask me how I know.

wet sump solution 2

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