Now where is this oil leak coming from?

Someone had given me the end of a old cylinder , a few mm thick , about the dia. of the round holes ( less than the retaining clip ) Had a bolt thru same as centre , thread . ( clutch diaphram toole )
Sorta thing ( std. or that ) a hillbilly engineer can whip up easy .

Though service tools are a good deal less cost relitive to centuries past .

ONE you do need , is the Timing Cover OIL SEAL GUIDE . again , tuppance , or whip one up .

So you pulled the outer primary cover off? How much oil did you retrieve? More than 7 oz's?

Thanks for all the goodmadvice guys. I havent had a chance to work on it as my wife gave birth to our first 3 weeks ago so things are very hectic around the house at the moment. I hope to be able to get to it soon though. I do not think that its the gearbox...the leaking oil doesnt smell like gear oil so i guess that helps narrow things down a bit. I am going to pull of the entire primary and replace all the gaskets and seals wheni get time. I will let you know what i find. My guess is that its the seal from the motor leaking into the chaincase. I guess i will soon find out. Thanks again for all your help and advice.

Johnnymac said:

Thanks for all the goodmadvice guys. I havent had a chance to work on it as my wife gave birth to our first 3 weeks ago so things are very hectic around the house at the moment. I hope to be able to get to it soon though. I do not think that its the gearbox...the leaking oil doesnt smell like gear oil so i guess that helps narrow things down a bit. I am going to pull of the entire primary and replace all the gaskets and seals wheni get time. I will let you know what i find. My guess is that its the seal from the motor leaking into the chaincase. I guess i will soon find out. Thanks again for all your help and advice.

Click to expand...

Just to be clear, oil blowing by the crank seal doesn't mean the seal is bad. It is more likely due to excessive crank pressure or from wet sumping from the oil tank.

The lower bolt holes that hold the inner primary to the case are notorious for leaking oil into the primary. When the oiltank leaks past the oilpump while sitting, it fills the lower part of the crankcase and runs into the primary from those bolt holes. If the oil level is too high ( not needing to be level with the felt seal) the chain will fling it all around the cavity and will seep out the felt. I suspect bronze clutch plates or clutch issue might be evident also.

The felt is not intended for sealing. Yes, it is a seal but it allows for atmospheric pressures to be equilized. It is basically to guard from dirt.

On the diagram...Which line is the correct line to add the PCV valve to? Line A or B?

An anti sump valve would go on the feed line that comes from the big banjo on the back of the tank. The diagram is a little unclear but the feed line connects to the outboard tube. I think you have this labeled as "Line B".
A reed/PC valve would go on line number 44, the breather line.

Before venturing into these updates, do your homework and study why they are needed or not. Particular attention should be given to anything being attached to the oil feed line. Choose ONLY a proven item for this solution.

Breather valves are a little more straight forward as long as they are connect in the right direction.

pvisseriii said:

An anti sump valve would go on the feed line that comes from the big banjo on the back of the tank. The diagram is a little unclear but the feed line connects to the outboard tube. I think you have this labeled as "Line B".
A reed/PC valve would go on line number 44, the breather line.

Before venturing into these updates, do your homework and study why they are needed or not. Particular attention should be given to anything being attached to the oil feed line. Choose ONLY a proven item for this solution.

Breather valves are a little more straight forward as long as they are connect in the right direction.

Click to expand...

I am confused, my breather line from the Oil Tank (shown as #45 in the diagram) connects to the back of the air filter plate.

Johnnymac said:

I am confused, my breather line from the Oil Tank (shown as #45 in the diagram) connects to the back of the air filter plate.

Click to expand...

[14] on the diagram should connect to the air filter plate.

(Note that the '72 parts book oil tank diagram shows the oil lines incorrectly drawn so that filter assembly appears to be connected to the oil feed pipe-which is wrong! Later parts diagrams show it correctly)

Lines a and b are oil feed and return lines, they have oil in them all the time when it's running. Do not put a pcv in either of those lines. The pcv would go in the line that is coming from your crank to let the pressure in the crank out. Mine is altogether different so someone else will have to tell you which hose that is.

Dave
69S

Johnnymac said:

pvisseriii said:

An anti sump valve would go on the feed line that comes from the big banjo on the back of the tank. The diagram is a little unclear but the feed line connects to the outboard tube. I think you have this labeled as "Line B".
A reed/PC valve would go on line number 44, the breather line.

Before venturing into these updates, do your homework and study why they are needed or not. Particular attention should be given to anything being attached to the oil feed line. Choose ONLY a proven item for this solution.

Breather valves are a little more straight forward as long as they are connect in the right direction.

Click to expand...

I am confused, my breather line from the Oil Tank (shown as #45 in the diagram) connects to the back of the air filter plate.

Click to expand...

Do you see the little reducer at the end of 44 , number 46? That is the connecter for the 2 lines. This is a popular spot to put a reed valve. On "MikesXS units, you simply eliminate the reducer and put in the valve. The input fits on the bigger line and the output fits on the smaller line. Easy peezy lemon squeezy.

Some will argue as to the best position for this valve stating that the closer to the casing the better. It is my contention that if not right against and mounted on the case as many people have, then put it up at the tank to make a natural 90 degree fit. Oil that passes up the line can drain back down. If the valve is mounted too low yet not far enough to heat up to help with condinsation, then oil and white crap will form in the valve and the reed action will be null. Kinda like blowing on a sax. Blowing air is one thing but try playing one with 50w oil in your mouth. The music is not so sweet.

That being said, I do not know what you have there. Pure stock? Unless you give details of your particular setup, I/we can only assume and you are left unclear. Pictures are good. You don't hear of too many Combats with the stock aircleaner box. I assumed that yours was like many others. I think this is because or the crank pressure issue and too much oil being pushed into the aircleaner that many people eliminate the stock system in favor of a K&N unit and vent right to the tank with the number 46 reducer. That little side pipe for the chain oiler also gets capped.

Thanks guys, i must have had a case of the mondays. Mine is set up correctly. I dont know why i though the the lines were switched. I have ordered the pcv valve from mikexs. I have to wonder how much it actually does considering the lines that it attaches to arent exactly high pressure lines. The tube from the breather to oil tank isnt even held on with a clamp....it is just slipped over the end.

The Chain Oil was useually refered to as getting oil everywhere BUT the Chain .

Blocked breather on say a diff or gearbox , on heating up on a long run , pressureises .
Which tends to force things out someplace . Negative pressure's quite the opposite .

Basically PCV valves and other tripe are for loose old things with BLOWBY and fumes , degeneracy , and ailments .
Therefore irrelevant to first class top line contraptions .

Usually subject to the process of erradication .

Looking at the catch bottle on raceing machines , the things at full wellie periodically , so the high flows carry Oil Mist .
This seperates in the catch bottle .Periodically eptied .
possible to set up oil system akin to radiator overflow tank with seperate breather catch tank . HOWEVER ,
ordinarilly the OIL TANK is acting as the Breather Chamber , therefore requires a litre of ' AIR ' volume free.

Overfilling the thing , say one of these suckers that wet sumps on start up where the oil tanks been topped up before start up , the oil in the sump overfills the oil tank . Given a bit of hoof , the air from the breather pipe doesnt have space or time to seperate ,so It Oils the Chain . :mrgreen: which brings us back to where we started . :wink:

Hi Johnnymac,
Do a search on the forum in the upper right hand corner for "wet sumping" and "crankcase pressure" to get a better feel of whats going on. It should take a couple hours to sift through the info but should be done.

Basically PCV valves and other tripe are for loose old things with BLOWBY and fumes , degeneracy , and ailments .
Therefore irrelevant to first class top line contraptions .

Click to expand...

Reed type PCV valves on the Commando are to reduce crankcase pressure. Blowby is another issue. There are a lot of Commandos that no longer leak oil ,not to mention a gain in horsepower, after installing a reed type PCV valve.

Definately . My Blue . PCV meaning the old clack valve in the rocker breather line ( automotive ) to me .

This ' REED ' though , is a Negetive Crancase Pressure device , a NCV ? :lol: :cry:

My Commando , put together useing ' pliobond ' for sealant & std. Gaskets , as they did then ,
got the right case to barrel rear damp spot , after 8000 miles , as they all did , then . Used the
N.O.C. case / breather mods ( 1980 ) .

Is this still a failing ( eventual slow weep , case to barrel , aft right ) on a high milage Commando these days ?

Remarks directed ' The Opposite ' ( Negative Pressure ) were in regard to the reed valve keeping the oil inside .

The old N.O.C. trick was to shift the breather to the magneto position , increaseing the effe ctive working volume.
Same principal was behind Triumps Crankcase to Primary vented set up . Double Volume = Half pressure fluctuation .

Matt,

I think the problem of leaking crankcases became more apparent when the primary belt drive arrived. Once the belt was installed, I noticed the crankcase seal was leaking. I know I changed many a crankcase seal on my belt drive 72 Commando only to have oil in the primary case a short while later. Finally, I installed a XS 650 PCV valve. Viola! Dry primary, as well no more leaking tach drive.

Thank you guys. One item that i keep hearing frequently is that over filling with oil is very bad. I did recently change the oil with mobile 1 15/w50. I filled it slowly to the "L" on the dipstick. Then i ran the engine for a while, then rested, restarting and checking again adding oil until it reached the H on the dipstick..... I am now thinking that could have contributed to my oil leak issue as I have read that some only fill to "L" at the max.

Johnnymac said:

Thank you guys. One item that i keep hearing frequently is that over filling with oil is very bad. I did recently change the oil with mobile 1 15/w50. I filled it slowly to the "L" on the dipstick. Then i ran the engine for a while, then rested, restarting and checking again adding oil until it reached the H on the dipstick..... I am now thinking that could have contributed to my oil leak issue.

Click to expand...

Not my intention to start another oil debate, but I'll pass along what the owner of Web Camshafts told me about using Mobil 1. DON'T! I think it has to do with the lack of zinc additive in Mobil 1.

JimC said:

Johnnymac said:

Thank you guys. One item that i keep hearing frequently is that over filling with oil is very bad. I did recently change the oil with mobile 1 15/w50. I filled it slowly to the "L" on the dipstick. Then i ran the engine for a while, then rested, restarting and checking again adding oil until it reached the H on the dipstick..... I am now thinking that could have contributed to my oil leak issue.

Click to expand...

Not my intention to start another oil debate, but I'll pass along what the owner of Web Camshafts told me about using Mobil 1. DON'T! I think it has to do with the lack of zinc additive in Mobil 1.

Click to expand...

Thanks Jim, what do you use? The only reason that i used mobile 1 was becuase it was recommended in an article i read entitled:

Temperature and Lubrication of the Norton Motorcycle Engine Originally published as a series of articles in the Norton Notice,
The monthly magazine of the Norton Owners Club of Northern California
©1993-2000 by Alan Goldwater. All rights reserved.

Another thing that might help. I removed the bolts from the inner primary to the crank and replaced them with studs and nuts, unc in crank and unf in primary, you can get 1" ones at your local auto store for a few cents. Red locktite the studs in the crank after thoroughly cleaning the crank threads. That should stop any migration from the engine to the primary. It also makes it easier to put the gasket (if you use one) and primary inner on. The bottom stud and nut will have to be ground down a bit to keep from contacting the primary chain.

I use Valvoline VR1 racing SAE50 in my bike, it's like honey and has the higher zinc content in it. Keeps the oil pressure up even at idle.

Just my preference.

Dave
69S