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Wet Sumping. An effective repair. (2015)

Discussion in 'Norton Commando Motorcycles (Classic)' started by kerinorton, Jul 27, 2015.

  1. Brithit


    Feb 22, 2005
    I know some of our members refer to the Velo check valve as a bodge, but as someone who has owed three Velos ('53 MAC, '66MSS, and '59 Venom) they all had check valves and they all worked. That is, they slowed down or stopped wet-sumping. The spring is a tiny conical thing, and is extremely light. A wisp of a thing. From my point of view, another thing that makes the Velo ball valve different is that it is mounted in a housing directly under the oil tank. Not an aftermarket part mounted downstream in an oil line. I have never heard of one sticking shut and destroying an engine. The biggest problem with them is they don't hold the oil. A Nitrile covered ball is one of the mods people do to Velos. Never tried one. And yes, you have to make sure that your oil lines are very tight and have no air leaks. All of the Nortons I've owned wet-sump a bit - even my MKIII. Never been a problem. I've heard "stories" of wet-sumping causing anything from bent rods (!) to blown out drive side seals. But, never first hand stories! The worst I've done is a little minor fogging for mosquitoes.
  2. Bernhard


    Apr 20, 2011
  3. Johnnymac

    Johnnymac VIP MEMBER

    Oct 8, 2011
    Re: iiRe: Wet Sumping. An effective repair.

    I have the AMR mod on both of my Nortons. My Atlas used to lose the entire oil tank in a week then manage to weep out anywhere it could. Now I don't have a drop under the bike and no wet sump issues.
  4. Brithit


    Feb 22, 2005
    I may have the nitrile ball thing wrong - it may be a solid nitrile ball. The Velo owner's club sell them.
  5. N0rt0nelectr@

    N0rt0nelectr@ VIP MEMBER

    Sep 15, 2014
    Just did the oil pump rebuild yesterday. Had an extra oil pump that I reduced the end float on, swapped it out for the original one.
    Need to retime the bike and start it up.
    John in Texas

    "]I recently rebuilt my 850 engine which used to drain nearly all the oil from the tank in a week. Part of the rebuild was to reduce the end float on the oil pump gears. Since the rebuild, I rode the bike once before going on holiday. 3 weeks later, the full tank had only gone down to the lower mark on the dipstick. Bike started up ok and didn't smoke. I did another 50 k ride and the oil level was at the top dip stick mark when I got back. I had installed a manual shut off valve in the supply line coupled with a micro switch to prevent starting when the valve was off. Looks like so long as I ride once a month, then that valve will never be needed again.

    I can only recommend guys with wet sumping problems to remove the oil pump and using wet and dry and a granite block, to rub the sides of the pump down to get closer clearances on the gears. Takes some time and effort but looks like it is worth it. My 14,000 mile 750 only wet sumps if you leave it for a year.

  6. Tristan Gallagher

    Tristan Gallagher

    Aug 3, 2019
    Hi Gents, sorry about the late arrival.
    (Luvly vinnie, btw, well played sir!)
    I have a 650ss just finished the restoration from a barn find ruin. It wet sumps like a beast. Very bored with removing the plug and draining every weekend.
    You mention an AMR device. Can you please direct me to where I can purchase said wondrous contraption?
  7. kommando


    May 7, 2005
  8. L.A.B.

    L.A.B. Moderator VIP MEMBER

    Nov 20, 2004
  9. jseng1


    Nov 26, 2009
    My solution was unexpected and unplanned. I have a small aftermarket car oil filter located in the supply line feed between the oil tank and the motor. I did this long ago when I built a racing frame and ran the oil through the frame as an oil cooler. I was worried about abrasive brazing flux contaminants in the oil. The only thing is that you absolutely have to prime the oil line feed through the filter - use a temporary short piece of clear rubber hose connected to the feed hose by a short piece of metal tube), pull on it by applying vacuum via the clear piece of tubing in your mouth - pull then plug the hole with your tongue, repeat, takes about one minute till you see the oil come through). Once primed you quickly remove the clear hose (check that each end is topped up), re-connect the black rubber oil line and you're done with any contaminants getting to your motor. It works great, my motors last forever and on top of everything the added resistance prevents wet sumping. I also did the oil pump lapping trick. The oil level may drop a little in the tank but not much and then it stays there (it never empties). I always peek inside the oil tank to make sure oil is pumping the 1st time I start it after changing oil. I've been doing this for 30+ years with no mishaps.

    You can forgo the vacuum trick and wait about 1/2 hour for the oil to work its way through the filter and oil line (hang the hose over a container).
    Last edited: Aug 24, 2019

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