Wet Sumping Poll

The dangers of wet sumping or lack of continues to be debated. So in the interest of science:

  • I never knew about it until recently.

    Votes: 3 2.4%

  • I never worried about it, and never had a problem.

    Votes: 55 44.0%

  • I worried about it but never had a problem, installed a new seal on my lapped (or new) oil pump .

    Votes: 11 8.8%

  • I worried about it , never had a problem, installed a shut off or check valve.

    Votes: 5 4.0%

  • I worried about it, installed a modified breather system, no valve.

    Votes: 25 20.0%

  • I had a slight problem, like hard starting, installed a shut off or check valve.

    Votes: 19 15.2%

  • I had a problem, like a failed main seal, installed a shut off or check valve.

    Votes: 4 3.2%

  • I will always build a Norton with a shut off or check valve.

    Votes: 3 2.4%
  • Total voters
    125
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I just checked my 73 850 yesterday, the oil tank level is still good after sitting 2 months now for its winter storage. In April I will drain the sump and tank, install new oil filter and refill with 20-50 as I do every spring. Then again after 2000 miles.
 
If the bike has sat for a month or more then I just kick it through about ten times. I used to look into the oil tank and watch the oil squirt out of the breather pipe which - due to a home made reed valve - very effectively pumps any wet sumped oil out. I don’t look any more because post reed valve it spits oil all over
 
Few years ago I recall those forum members who declined to install a reed valve breather. Instead, they were convinced a crankcase seal made of unobtainium was the answer for stopping engine oil migrating into the primary case. Guess they’ve finally decided to go with a reed valve, or they quit posting flat earth illogic. Are they the same folks who put an obstruction between the oil tank and pump, maybe?
 
JimC said:
Few years ago I recall those forum members who declined to install a reed valve breather. Instead, they were convinced a crankcase seal made of unobtainium was the answer for stopping engine oil migrating into the primary case. Guess they’ve finally decided to go with a reed valve, or they quit posting flat earth illogic. Are they the same folks who put an obstruction between the oil tank and pump, maybe?
Click to expand...

Not just one snap but a double snap. Ouch.
 
Hi
Correct me if I'm wrong, but the yellow Commando in the video seems to have a MK3 timing cover. I thought these contained an anti-sumping ball (?) valve, but the video infers it has wet sumped?
(Starting a Commando in flip flops is rather cool!)
 
Staytite said:
Hi
Correct me if I'm wrong, but the yellow Commando in the video seems to have a MK3 timing cover. I thought these contained an anti-sumping ball (?) valve, but the video infers it has wet sumped?
(Starting a Commando in flip flops is rather cool!)
Click to expand...

You may be right, but I had one of those MkIII covers in '75 to '80, it never worked then! The valve just stuck open.....
 
SteveA said:
You may be right, but I had one of those MkIII covers in '75 to '80, it never worked then! The valve just stuck open.....
Click to expand...

If they stick open, can they also stick closed? Or at least partially closed?
 
MexicoMike said:
If I haven't ridden or started the bike in quite a while, I check the oil tank level with a flashlight. If the oil level is still above the feed line screen, I start the bike. If it's below the screen I drain the sump and dump the oil back into the tank.
Click to expand...

Same here. Mine has to be left a long time before the oil level drops enough to expose the filter screen though.

With the Comnoz breather the sump is emptied to normal operational level in seconds upon start up.

In my book, this just ain’t a problem.

I’ve nothing fancy or controversial in my oil feed. I just fitted a new ANIL pump when I built the motor. Seems to me that if the wet sumping ever does become a problem, it’ll just be an indication that a new (or refurbished) pump is in order.
 
I have a MKIII- wet sumps badly. It sat for a month (with fresh oil) before I was able to start it for the first time. I removed 400cc of oil from the sump before starting it. I had the updated check valve installed and the pump checked out (fine) by AMR. The old check valve was not stuck. I have several street bikes so the Norton will sit at times and I do not want to deal with draining the sump to go for a ride.
 
If you are contemplating an in-line shutoff valve I would advise you not to go that route, Gyro Gearloose contraptions included. I would double check the things you mentioned. The spring loaded shutoff valve at the output warrants a closer look.
 
Last edited:
One more: I had the AMR mod done and no longer have a wet sump problem.
 
As a Mark III owner I've often wondered if there would be any harm in "pumping" the wet sumped oil out by pushing the kill switch and letting the starter motor crank for 30 seconds or so to return most of the oil to the tank. Personally, if it's been sitting for a while and wet sumped, I drain and pour it back in the tank.
 
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