Severe Oil Leak

Hello all. New Norton 1974 850 Commando owner. Drove it around today had no problems, kind of weird noises, but no major leaks. I get on the highway to go to work and as I pull in to park I notice my right leg is drenched in oil as well as the bottom of the bike. Didn't have time to locate the leak but my pod filter was soaked. Any suggestions or theories are welcome. Will add image as soon as I learn how.

Was the tank low and you added oil before you started out? Is the source of the oil the hose that is from the top of the oil tank and going into the airfilter housing. That is the engine breather.
Chances are that the engine has "wet sumped" if it has been sitting awhile (on some bikes only a couple of days is enough). Not sure if you are familiar with the term but basically in old Brit bikes, if they sit for awhile the oil in the tank(sometimes about all of it) leaks past the oil pump and ends up in the sump. When you start the bike the excess oil in the system often comes out the engine breather pipe, often with a fair amount of smoke out of the exhaust.
First thing to do is drain the sump. That way when you fill the tank you won't have excess oil in the system. An engine that isn't wet sumping will only have about a cup or so of oil in the sump. Once you get the oil out of the sump (okay to use again if you use a clean container) fill the tank so that it reads about halfway between add and full. Get the bike running and check for return of oil back into the top of the tank. Ride it for a few miles to get it warmed up, then check again while the engine is still hot and top off if necessary if not up to the halfway mark. I always run my Commando at the half way mark as it tends to puke anything else more than that out the breather.
Checking the oil on these is kind of a two step process. Always check it right after a ride and top off if necessary. Then before you start it the next time check the level again. If its low, the oil is going to be in the engine sump and if you top it up with more oil, when you start it you will blow oil everywhere. Drain the sump if the level is below the bottom of the dip stick and put that oil back in the tank. If its just at the bottom of the dipstick the pump can clear the sump of that amount in a about a minute. Just don't add more oil without draining the sump.

Thanks for the information. If I'm understanding you right this means that I need to drain the sump and then add that oil back to it, which will prevent the large amount of leaking, which is a temporary fix, that has occured. After doing so check the oil and add more as needed? I'm struggling with understanding how it drains to the bottom or how adding more will prevent this from happening. There's a great possibility that I'm misunderstanding the part that prevents the problem. Thanks again for the help by the way.

The oil you drain out of the sump needs to go back into the oil tank.
Let me try to be a little clearer. These are dry sump engines. One side of a two chamber rotary pump inside the engine draws oil from a hose on the bottom of the oil tank and pumps it through the crankshaft to lube the rod bearings. The excess oil also splash lubricates the cylinder walls, main bearings and cam bushings. If also pumps some oil up a small hose to the rocker arms. The oil all drops to the bottom of the engine sump where the other chamber of the pump scavenges it and returns it through a hose to the top of the oil tank. When the engine is running there is not a lot of oil in the sump, maybe a cup or so. The rest is in the oil tank. When you start the engine it's always a good idea to remove the oil cap and look for the return flow. It's a good indication the oil pump is functioning correctly.
Okay so now we shut the bike off. It has a full oil tank and a cup of oil in the sump. The oil tank is higher than the oil pump and sump and oil from the tank wants to drain through the pump into the sump by gravity.
When the bikes were new the close tolerances of the gears in the oil pump wouldn't allow much oil to get past. However, with miles and wear the pump clearances increase and oil starts to leak past the pump and fill up the sump and drain the tank when the bike sits awhile (some bikes only a couple of days). Now we have a problem. While the scavenge pump can handle some excess oil in the sump a whole tanks worth overwhelms it. This excess oil is going to exit the engine in three ways, sucked up passed the rings and burned (exhaust smoke) or the pressure of the pistons on the downstroke will force it out the engine breather back to the oil tank or it will blow the crankseal and end up in the primary.
To make matters worse if you are not familiar with this problem, you look in the oil tank before starting the bike and see the tank is low. Not realizing that the oil has leaked from the tank and is in the sump, you dump another quart in. Now the system has more oil than it can hold and it will come out the tank breather line which I believe on your bike goes to the aircleaner.
The key is to have correct amount of oil in the system based on the recommended amount in the shop manual. If the bike has been sitting and you look in the tank and it is really low, pull the sump drain and check to see if that is where it's hiding. Then always check your oil level hot right when shut off before any of it has a chance to leak to the sump. If you haven't got a shop manual and parts book yet pick one up and study the lube sections to get a picture of what I'm talking about. This also might help.
http://www.oldbritts.com/oillines.html

Check your oil lines to the head, usually right where they connect to the fitting at the head. You generally wont see them leaking at idle but when you run the throttle up, they'll start to spirt.

+1 on what Pete V said. My bike had a gasket fail on the end cover on the right hand front rocker shaft. Oiled down right boot.
My rant on wet sumping may not be the cause of this leak. Still worth understanding the wet sumping problem though. It's a rare Commando that doesn't do it to some extent.

Thanks all for the help. Going to shake your head but again bear with me as I have zero experience. I've been reading up on the rocker feeders. my tubes are non existent. There's nothing there but two nipples on the right side and one on the left without tubes. There is however a melted tube that appears to be a banjo bolt headed to the gear box? Could this be where all the oil has come from? Since it only leaked this way at high RPMs, such as highway travel.

Look at this link again.
http://www.oldbritts.com/oillines.html
You will see the line going from the back of the engine up to the right hand side of the head and then a cross over line to the left. Don't mess with the plastic replacement lines,get one of these or similar unless you are an originality purist.
http://www.ebay.com/itm/Norton-750-850- ... 60&vxp=mtr
You have to replace these lines before you ride the bike again. Your rocker shafts are getting no oil and you are dumping your engine's life blood on the road. Did you just buy this bike? I think a visit with the seller would be in order.

Here's the damage.




I was right in suspecting there being a problem for these not to have lines on them, I just didn't understand why they weren't leaking before when I had road the bike. In theory I can just get any type of heat resistant hoses and place on those nipples as a temporary measure correct? I'll definitely be investing in the stainless ones.

OMG :shock:
Well, you found the leak.

No temporary fixes, get the right parts and do the job correctly. Those hoses see full oil pressure, as high as 80 psi when the oil is cold. Make shift hoses fitted over the nipples are likely to blow off. You risk serious engine damage if they do.

So I purchased the ones you recommended htown. Be a week before there here. Guess that gives me time to clean the mess that the oil left.

Once these lines sprung a leak the oil pressure feeding the crank would have dropped to nearly nil, as luckily you did not run out of oil there would have still oil available to the crank and the centripetal forces would have kept some oil pressure at the big ends. But you need when the lines are fully back in place and riding just be aware your big end shells may be worn so do an oil pressure check to give you an idea of any wear. Note there is an oil pressure relief valve in the system which should be set to 50psi, only when cold should you get over 50 psi and if its set wrong then you may get lower so that will need checking too. Replace the lines with Stainless as previously recommended, even the factory nylon lines were prone to hardening with age and then cracking.

Hi

My right leg was full of oil, once.
The oil came from tachometer driven....

Vidar

As posted above it would be a very good idea to check the oil pressure at this point to see if the rod bearings suffered undue wear when you rode the bike with low oil pressure due to the missing hoses. You can use a standard automotive type pressure gauge with a 1/8npt connection. You need some adapters. The line is plumbed off of the banjo bolt on the left hand side of head. You replace the single bolt on that side with a double banjo bolt, the existing banjo from the cross over feed line goes against the head and a second banjo with an adapter to the hose line on the gauge goes on top of it. Here's some links for the hardware.

You need a double long banjo bolt, banjo fitting, suitable hose, and adapter from the hose to 1/8npt.
The double banjo bolt is available from:
http://www.ebay.com/itm/Banjo-Bolt-Doub ... a4&vxp=mtr

The banjo fitting, already attached to a hose, and AN to NPT adapters are available here: https://www.pegasusautoracing.com/group ... BRAKELINES

Pegasus also has the copper washers as well.


This link at the bottom shows the concept for a permanent guage. Principle is the same for a temporary test guage.
http://www.oldbritts.com/38_240010.html

sturrubiarte said:

I was right in suspecting there being a problem for these not to have lines on them, I just didn't understand why they weren't leaking before when I had road the bike.

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That's a good question. Actually, the question really should be " why wasn't there oil leaking (being pumped) from the rocker feed banjo at the back of the timing case?"
If the oil pump is working properly, that should happen even at low revs. Unless it's been plugged somehow. If it wasn't plugged and yet didn't leak until high revs, the oil pump is then in question.
+1 on htown's suggestion about a visit to the seller.

Spoke with the previous owner. He's a good guy IMO just overlooked that the lines he placed would melt, admittedly. The temporary ones I've placed have better routing and higher heat protection. Will post some pictures when I place my new stainless ones. The pressure idea is a good one, heard and seen it before, should probably have done that before but I'll need a little more capital to complete that project. The wife and I are a young couple so it looks like we'll start the eye rolling on her part early in our marriage :lol:

The question is were the rod bearings compromised from riding at highway speeds with very low oil pressure. You said in the intial post the engine was making weird noises. Knocking? There's only 3 ways to find out if the bearings are okay. One, relatively inexpensive, put an oil pressure gauge on it. If you have decent oil pressure, chances are they are okay. Two, costly but answers the question definitively, tear the engine down and physically inspect them. Three, either free or very expensive, ride the bike and hope for the best. If no rod lets go and pokes through the cases they were fine if it does you could be looking at 2-3K$ for a complete engine rebuild and possibly end up with non matching or welded cases. It looks like you are ignoring the advice to not cobble on makeshift oil lines and wait on the proper parts. Now you think checking the oil pressure is something you might do in the future. You have a nice looking bike there based on the pictures. These old things aren't complex but they don't respond well to heavy handed treatment. Good luck with it but I'm outa here!

I sincerely appreciate the help but if the motorcycle I bought is that delicate then it's my fault for making a poor choice to purchase and should have stayed with my bullet proof xs11 and just been happy. Guess time will tell the mistake this will amount to.

sturrubiarte said:

I sincerely appreciate the help but if the motorcycle I bought is that delicate then it's my fault for making a poor choice to purchase and should have stayed with my bullet proof xs11 and just been happy. Guess time will tell the mistake this will amount to.

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Interesting comment. So you didn't realize you were buying a 41 year old motorcycle? They aren't fragile, but require some mechanical ability at least basic knowledge. This is older technology...not plug and play.