Has my Cafe'd bike wet sumped, & what should I do about it?

As some may recall, I've recently acquired two 750 Commandos. One bog stock, & one Cafe'd. The stock one is a fixer upper. It starts easy, but runs rough. The Cafe bike is a looker, which ran well when I bought it, but has been hard to start since it got trucked 4500 Kim's to my place. In fact I've only started it once, & that was after a fair bit of kicking. Though it did start easily for the rest of that day, while the engine was warm. It hasn't ran since. I'm not too concerned right now, as it's just a Lounge Ornament, until I recover from a shoulder replacement I'm getting at the end of July. But a slow oil leak underneath the sump, & an empty oil tank, has me concerned that the bike has wet sumped somehow, on it's long journey north. It does feel like it's got a lot of resistance when I kick it over, like it's turning in treacle. My stock bike turns over much easier.
My questions are 1) Does it sound like a wet sump problem? 2) Will leaving it like that, while the bike's off the road, do any harm? Or could it help to keep the bottom end lubed up? 3) my engine's been heavily modified, with the single Mikuni, belt drive conversion, even a hydraulic clutch! So I'm not sure what breather conversion's been done, but I'd be surprised if it hasn't got something. I'll be contacting the Seller to ask him what's been done, & whether the bike's ever wet sumped before. I strongly suspect that if I looked in the inspection holes on the primary cover, which I won't do while the bike's in my Lounge, I'd see a lot of oil on my belt drive. So is it hurting the belt to sit in an oil bath? In short, considering the bike could spend up to another year as a Lounge Queen, should I fix the wet sump soon, or leave it until I put the bike back on the road?

Re: Has my Cafe'd bike wet sumped, & what should I do about

Old Scratcher said:

Does it sound like a wet sump problem?

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Yes, it sounds like the oil has drained to the sump.

Old Scratcher said:

Will leaving it like that, while the bike's off the road, do any harm?

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Shouldn't do any harm, the only thing to be concerned about would be if the oil is seeping into the primary drive. If it bothers you then the simple answer would be to drain the oil from the sump and store it in a container until you intend to get the bike running again.

Re: Has my Cafe'd bike wet sumped, & what should I do about

Cool. Great idea. The simple solution's usually the best. What do I need to do to stop it happening again?

Re: Has my Cafe'd bike wet sumped, & what should I do about

Sumping is a common issue with the Norton motor. There are endless posts on this subject if you look around this forum. My experience is I don't worry about it and when you go to start it if you look into the oil tank and can see the mesh filter on the oil feed line on the bottom the oil is in the sump. Get a good CLEAN oil pan and drain the oil from the sump and pour it back into the oil tank. Start like normal and enjoy. If you do this more than a couple of times don't forget to add a little more oil to make up for the oil that sticks to the pan and does not get back into the tank.
As for you belt dive primary there should be no oil in the primary. You need to seal that up so no oil can get in there. Again peruse this forum and all you need to know is available.

Re: Has my Cafe'd bike wet sumped, & what should I do about

Old Scratcher said:

What do I need to do to stop it happening again?

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Norton twins tend to drain their oil down to a lesser or greater degree when left unused due to the design of the pump and force of gravity, most owners accept this as a normal occurrence and live with it, however, there are ways to reduce the rate of drainage-such as the Mk3 or AMR timing cover modification, or positioning the crank at TDC, but if you want to stop it completely then the answer would be to fit either a manual or automatic valve in the feed line. Personally, I wouldn't recommend either.

Re: Has my Cafe'd bike wet sumped, & what should I do about

Hi All.
I have a part, but ready to mount on my 750, the 850 ES timing complete with oil non returne valve.
Is a good idea to use or it works without great results?
Thank you.
Piero

Re: Has my Cafe'd bike wet sumped, & what should I do about

pierodn said:

I have a part, but ready to mount on my 750, the 850 ES timing complete with oil non returne valve.
Is a good idea to use or it works without great results?

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Yes, that should slow down the rate of drainage-but don't expect it to stop it completely.

Re: Has my Cafe'd bike wet sumped, & what should I do about

L.A.B. said:

pierodn said:

I have a part, but ready to mount on my 750, the 850 ES timing complete with oil non returne valve.
Is a good idea to use or it works without great results?

Click to expand...

Yes, that should slow down the rate of drainage-but don't expect it to stop it completely.

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Hi Les,
I mean, thank you.
Ciao
Piero

Re: Has my Cafe'd bike wet sumped, & what should I do about

Oil tends to leak past the oil pump gears - faster or slower depending on oil pump condition but even a rather worn out oil pump can still supply enough pressure so a non issue operation wise. Both the Combats I got were both stored long enough to empty oil tank, 1st one over a winter and 2nd one a decade+ but neither of them leaked a drop outside the full of oil crank cases. The upside of wet sump is it can reveal a weakness in seals or fasteners and preoils the cam lobes before combustion speed hits. The down side is harder to kick over if so cold oil is thickened up and if adding oil to tank w/o clearing the wet sump, excess is pumped out oil tank vent to spread on floor. BTW if any type/brand/composition of belt you have is affected by oil then you have a DEFECTIVE Belt brand/make/composition as all the vendors asked and all my oil exposure testing says belts impervious to engine oil same as cam belts so common nowadays. Its possible to flood primary with enough oil it can lift belt off basket teeth to drift off clutch but that is a hydraulic surfing issue not a belt solvent damage one. There are way more horror stories of anti-wet sump devices failing than any other single let down/breakdown issue we hear of, so beware and search up <wet sump + accessnorton> on google for scope of wet sump good and bad to base decision and philosophy on. Btw make sure primary is always adjusted on seemingly Too Slack Cold and Double Check on increasing ride intervals till full heated to make sure its not thermally tensioned to point of bending shafts. I am a black sheep here - by liking some wet sump vs those that want no wet sump becasue they have found weak crank seals and case leaks they blame on wet sump as cause rather than just revealing their Commando faults to fix. Best to check oil level on shut down rather than before start ups.

Re: Has my Cafe'd bike wet sumped, & what should I do about

Thanks for the replies everyone. It's good to hear the variance of opinions on the subject. I think I'm in the it's not that big a deal & can be useful for showing up weaknesses camp. So I'm not too worried, which is a good result in itself. I will drain it today & pour it back in the tank, just to see if it's any easier to start. It's an interesting experience to learn the ins & outs of a 43 year old bike that's had it's faults thoroughly analysed, & fixed where possible, by a dedicated group of owners. & while I could search for a lot of these answers, I'd like to get the current state of thinking about what works & what doesn't. So please bear with me & my dumb newbie questions, as there is a method to my madness. & it really is the quickest way for me to get up to speed with everyone else here. The thousands of years of experience represented here is an amazing resource. But it takes some time to take it all in. So I'll take any short cuts to enlightenment that I can. :mrgreen:

Re: Has my Cafe'd bike wet sumped, & what should I do about

What are the possible negative consequences from running a bike that's wet sumped?

Re: Has my Cafe'd bike wet sumped, & what should I do about

Some will say it's possible to blow the crank seal by the primary. I used to use my bike occasionally when it was relatively new in the early 70's without even knowing about wet sumping and nothing happened. I'm sure there were many times nearly all the oil was in the sump when I started it. Now I'm in the camp where I've got a ball valve in the feed line from the tank with a ignition cut off switch on it. Lots of people will say don't go there too. I only find it helps with the constant dripping of oil when the sump was always full. That's about it. It's really nothing to worry about unless you want to.

Re: Has my Cafe'd bike wet sumped, & what should I do about

I managed to blow a seal on my MK 3 by revving it a bit too high with a full sump. That bike takes a long time to wet sump, so I haven't fitted an antisump valve to it, just try to ride it more often and take it easy if the sump is somewhat full or drain it if really full.
If the sump is really full and the tank is completely dry, the pump might air lock and fail to deliver oil, so not a good idea to start the bike with no oil over the intake screen in the oil tank.
Also, with my 650SS, running that bike with a full sump causes an extreme smoke out which cannot be good for the combustion chamber or valves. I have seen valves from some old oil burning engines heavily encrusted with black crud
and combustion chambers full of the same coke. This must be happening when a wet sumped engine starts up and puts out a smoke cloud for several minutes. So opinions vary, but I don't see the really full sump as a healthy thing for any dry sump engine.
It's one of those things that people might "get away with" for quite awhile, but that doesn't mean it is not harmful to the engine. If it was truly such a wonderful condition, then the makers would not have taken steps to stop the wet sumping (mk3850)

Glen

Re: Has my Cafe'd bike wet sumped, & what should I do about

Ugh Glen these are supposed to be dry sump engines and as you have found excessive wet sump can reveal failing seals of oil pump clearnaces, crank &or rings &or head guidles and or head and other gaskets. Wet sump does not cause these various leaks which if present still tend to over oil and foul plugs even w/o any wet sump. Not saying its a bad idea to empty excessive wet sump but its a messy hassle and many w/o excessive or defective stuff above get away fine with wet sump starts. Usually our Cdos loose enough oil when used often enough theres is little wet sump between uses one can just add some oil to cover the tank out let and start w/o any oil stravation interval - which always exists some anyway as takes a dozen or more sec to develop pressure to crank and head to drain back on cam. MK3 may be excessively prone to wet sump issues though so plan ahead on extra Cdo worship service - before just riding off.

Re: Has my Cafe'd bike wet sumped, & what should I do about

hobot said:

MK3 may be excessively prone to wet sump issues though so plan ahead on extra Cdo worship service - before just riding off.

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Steve, why would the MK3 be excessively prone to wet sumping? Just the opposite is true, the MK3 is the one model which has a built in antisump valve on the pressure side, so wet sumping with the MK3 tends to be less of a problem than with earlier models.
My MK3 must sit for at least two months before all of the oil from the tank makes it's way to the sump. Anything less than a month between rides and I just check for oil cover on the screen then start and ride away, no smoke.
At a month of sitting the oil tank is still about half full.

Glen

Re: Has my Cafe'd bike wet sumped, & what should I do about

Come on, Steve. Dry Sump only mean it has a separate oil tank and is not to be taken literally. I think all dry sump system are prone to wet sump. Is it normal? What's normal? Is it common? Totally!

Re: Has my Cafe'd bike wet sumped, & what should I do about

Ugh I am as conflicted on wet sump side effects as any one but detest being a pre-ride mechanic so will continue to test my appalling practice. Each to his own sense of cold kick off effort, risk of fouling or past bad experience with wet sump and imfamous anti-wet sump devices. There was a brilliant solution photo posted with all kinds of reflex sneering nose down comments on a barn find that had a spigot sticking off the low rear of TS case. I too at first look made a face and shook head then it struck me how clever it was ... to just put a can with spigot valve open and collect excess to dump back in tank. Would set a helpful level of wet sump for cam but not huge splashes for minutes onto bores. I have considered JBW a ring magnet around sump hole then a disc magnet as cap for tooless non thread damaging quick drain w/o taking apart to be a tedious machinist too. Then I remembered how many times hi centered limbs brush roots and of course rescue loading into PUs. My heart goes out to MK3 owners.