Bored with wet sumping

If you are only leaving the bike a week between rides I would give it a go without draining the sump.I would take a reading on the dip stick before hand to give me an idea as to how much has drained down as starting point for assessment later. Meanwhile just let the bike tick over for a minute or so and see how much oil has returned to the tank. It would be a good exercise to do the above to give you reassurance as to the amount of oil your system is wet sumping and how long tick over needs to be before you take to the roads. I get away with this regime on my Matchless twin to a point until I think the wet sumping has had a while to fill the chaincase as there is no effective way of preventing it filling up with oil due to the thrust washer with its scroll oil thrower not working when the bike is laid up. Having a crankshaft seal on your Commando you should not have this problem and chaincase will not be affected in this way.  

"Many years ago .." of course, we used to ride the bike a couple of times a day, every day.

But I never bother so long as I can't see the outlet filter gauze in the tank.

When we were young and careless, our crankcases was so mistreated that excessive oil leaked out. Our oil pumps was not so worn out and it was a daily ride. We used straight 50 oil which don't leak through the pump as fast as a 20/50 oil. No knowledge of the wet sump problem. If there was no puddle under the bike it was serious because there was no oil left in the bike. I've witnessed  when a 650SS with too much oil in the crankcase blew the crank seal, filling the primary. I know that a roller cranked bike with a closed tap in the oil line can go ten miles before seizing. A plain bearing crank as a Commando will go much shorter.

How about running the engine for 10 minutes mid week?

https://www.feked.com/anti-wet-sump-oil-pipe-tap-with-switch-magneto-or-coil-ignition-systems.html  

All i use is a brake pipe clamp . Yes it a pain to drain th sump , pour it into the tank and mop up . I got a pair that look like surgical clamp. 7 inch long. .Position so it lies over the foot rest. First thing to take off . Then go through  the start ritual .petrol on tickle carbs . and kick over. Ride off with clamp in Belstaff pocket   

I too fitted a tap with electric cut-out to cut-off the electrics if left turned off and it worked well. I'm personally not too keen on the idea of squeezing the oil pipe with clamps as it might damage the tube or constrain the flow (particularly if it's braided) over the long-term (I am aware of quite a few folk doing this though).

If you cannot go at least 2 weeks without your bike's oil tank draining most of its contents then it is time to look for the cause(s). Generally with Commando engines the problem is down to a worn oil pump. The 6-start gearing means that it is turning twice as fast as its design speed so therefore is wearing out at least twice as fast. If you have to got to 50,000 miles of use in a Commando, then you have got to the point where a refurbishment or replacement is due. Get a replacement from Andover N. Their offering has been redesigned to eliminate all the flaws of the AMC rubbish and for the money could save an expensive engine failure. Next check the timing cover oil seal. Like all similar seals within a Norton engine/gearbox age and usage will take their toll. Replace it with a good quality dealer supplied item. Always fit a gasket between the respective oil pump and crankcase faces. Again heat and ageing can distort either or both. The gasket will help sort this. Below is the mating face of a Commando oil pump. This is the finish from new.

Refurbishment is the best solution, as above. In addition, replace the gears and machine them to the exact tolerance by building a rig to measure the  least oil passing through., so a bit at a time. Who is to say a new unit will be properly machined! 

Hello, I've been using grade 20/60 for 6 years because I only do long trips with luggage and the oil no longer goes down into the crankcase. My pump has 20,000 kms.

A local (to me) oil specialist motorspirit.co.uk at Bicester Heritage promote Penrite Enduro 25w-70 as the oil to use in place of straight 40 or 50 grade oil in classic bikes. It has a very high zinc content. I've used this in previous bikes but the oil in my 99 seems quite fresh so I have yet to change it out.

The most important thing with oil in a Commando other than the ZDDP content, is its ability to flow when cold, you want maximum lubrication in a rapid timescale and also maximum heat removal. I have used 5w40 for over 12 years and 10w50 as this gets around the engine ie over the cam and followers quicker. The downside is that it will wet sump quicker. The upper working end of the oil is irrelevant - believe it or not your Commando engine in the UK will not even warm the oil to the designed operating temperature where the oil is specified as XXw40 / 50 / 60 / 70 etc on our hottest of days. You can check this with a thermometer on the hottest of days on the banjo bolt on the back of the oil tank, I doubt it will be anywhere near 100 C.  The oil pump, the procedure for refurbishing is it the manuals, but it is not correct. It is critical to keep the wear faces in the exact same relationship when doing it, ie 'butterfly' the pump as you dismantle it and make sure it goes back together the same way. If you are going to replace or re-furbish your oil pump do it just prior to an engine build and use it, this will mean that any wear particles from the pump refurbishment will be removed form the bearings and the engine when the engine is stripped and cleaned the, the recently replaced or refurbished run oil oil pump can be bagged and put aside.  Wet sumping, I know of many engine failures due to the anti wet sumping valves, some the valve itself and some the operator. The latest version that is on sale in the UK must be wired correctly, but we have also noted that even when wired correctly they will not brake the circuit until the valve is half shut.  For those that wonder about the tappets and cam interface then measure the temp next to the spark plug and then measure the temp on the tappet tunnel - it gets hot, very hot, and thus the need for a decent supply of oil over the tappets and cam.  The Commando oil pump, will wear but even when well worn will deliver more than enough oil to the engine, by the time the pump is worn to the point it doesn't work you would have to have covered some serious 6 figure miles.  

I've heard it mentioned that starting a wet sumped engine can blow the crank drive side oil seal out. Not happened to me yet, I normally check to make sure the oil tank level is not below the strainer gauze before starting.

hello,  wonder what the effect of to much oil in the primary cover in the area of the alternator would be. with it slowly filling up the fine gap between the rotor and stator. would it have an hydraulic effect on starting. barry

I used mineral 20W50 in my Dommie 650 and generally had to add 500ml every 1000 miles. I then came across Pemco 20W50 Fully Synthetic.  5L for just £20 post free. On the container the label informs product of Germany. Last month I rode 1000 miles and only added a mere 200ml to top up the oil tank level. A smokey cold start is now a memory of the past. I am most impressed.

Philip, it's not fully synthetic though, the cannister reads ' synthetic blend', which is similar to semi synthetic I believe. Good price for an economy oil though.

Fitted a Mick Hemings Velo type anti-drain valve to my Mk 3 850 several years ago. Has worked just fine , maintaining a full oil tank up to the mark even with a 3 or 4 month lay up. Fitted as standard by Velocette on their bikes at the factory back in the day. Always check oil returning to tank on every start up letting it tick over for a couple of minutes while observing. When changing oil essential to prime valve using a clear plastic tube to suck new oil through before reconnecting valve.

Thousands of Velo owners have covered hundreds of thousands of miles without problems. All I would add (as a past and current owner of both a Venom and a Fastback) is

1. if you fit a Hemmings valve -- which uses actual Velo internals, as I understand it -- you might want to avoid the aftermarket nitrile ball offered by the VOC spares scheme: there have been claims that a backfire on starting can impale it on the knife-edge of the seat, with obvious consequences
2. The Holland Norton Works version uses a steel ball and nitrile seat, which should obviate the impalement issue;

The Holland Norton Works anti wet sump valve is here: https://www.hollandnortonworks.eu/en/exclusive-commando-parts Look for item #H08

Hi Mark  i like the idea of fitting a isolation valve with a switch which isolates the electric when valve is shut. Please could you tell me where you got it from. much appreciated   Regards Neal

A quick search found this https://www.feked.com/anti-wet-sump-oil-pipe-tap-with-switch-magneto-or-coil-ignition-systems.html I think there is other suppliers and don't know quality of this one.

I find that starting a wet sumped  motor  (Dommy) leads to oily plugs that will usually clean up if the motor is worked . But can give trouble if just bimbling about. I am fortunate that I can just rumble along for a mile at very  low revs while the sump clears . The motor runs ok on 10/40 fully synth but it uses more and can be a bit clattery. I am now back on 40 and its definately quieter. A 20/60 sounds a good compromise and will be tried  next. If PH says its good then , its good !. I have re-calibrated the low pressure head feed to give a little more oil, but this is tricky as there are no oil seals on Dommy valves and oily plugs can  become an issue with some plug  makes that absorb carbon into the insulator and dont self clean very well. At a recent group startup it was noticeable that my motor was easily the most quiet , (could not be heard above the racket !) ,so perhaps 40 was specified to cut the cacophony  !!.