Over oiling

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Still having lots of oil build up in the inlet cavity, I have removerd the head and valves and checked the oil drain hole which is totally clear and clean along with the route down the barrel and into the cases, I am wondering how much the drain holer is restricted by the valve spring retainer?

Also the oilway on the rocker is near enough oposite to the flat on the spindle, surely if the spindle was reversed (point in) then the oil will travel through this hole and down into the crank case?

The guides have no way of gripping oil seals, it is a very early head going by the casting numbers.

After sitting for a few days I removed the head and found lots of oil around the inlet valve side so this must be the trouble

Also another thing if anyone looks.

I have had GPM pistons put in and it looks like they have made rubbing marks fron and back, what should the clearence be? I didn't want to hear piston slap like so many others I hear, but also don't want it to sieze
 
Maybe the spindle to rocker clearance is blown out((worn)out of spec). That would definitely let more oil through.

My new "old" head had those Atlas inlet guides that would not take seals. I had them replace. Not much option there.
 
comnoz said:
High pressure head oiling didn't come along until the N15 and Commando in late 60's.
Click to expand...

The high pressure rocker oil feed started at 116372, so Atlas, 650SS etc. from 1966.

comnoz said:
The problems with no valve stem seal immediately became obvious.
Click to expand...

It couldn't have been that obvious, as, according to the available tech. info., inlet stem seals were not fitted until around 5 years later (from 149670, mid-late prod. '71 Commando).

MODELS AFFECTED:
DISTRIBUTION:
Commando - all years and models
No. N45
Worldwide (Trade Only)
motorcycles
PARTS INVOLVED :
EXPLANATION:
Inlet valve guide (old part No. NMT 2011)
New valve guides 062725 fitted with plastic guideto-stem seals 062726 have been introduced for the
inlet valves only of Commando models. The existing valve guides NMT 201 continue for exhaust
applications.
The new valve guides are similar to the existing guides except for the provision of a
groove above the valve guide collar. The groove is to locate the new oil seal. The latest inlet
guides for inlet applications only.
The seals are introduced to prevent oil passing between the guides and valve stems and being
burnt, causing excessive oil consumption. Under no circumstances must the seals be fitted to the
exhaust valve guides."

etc...

"May, 1971."
Click to expand...
 
As far as I can see there is just one, which is quiet chunky probably about 1/16

It does seem to get the oil upo there quick, I only have to press the kick start down twice and it will be pumping out
 
bigmike76 said:
As far as I can see there is just one, which is quiet chunky probably about 1/16
Click to expand...
Do you feel it is needed? And do you see good flow returning?
 
There is a good return flow, this can be done from the kickstart also, even on tickover there is a good stream
 
bigmike76 said:
There is a good return flow, this can be done from the kickstart also, even on tickover there is a good stream
Click to expand...

I would suggest removing the shim and/or gauging you oil pressure. Starvation is not you issue. Wait for others to chime in to see what they think.
Either way, you still have the valve seal issue.
 
I think I may have found the problem-

Under the valve retaining washer according to the diagram there should be a heat washer of some kind, this wasn't fitted so I am thinking that the bottom retainer was sitting staight onto the head and blocking the drain hole.
 
bigmike76 said:
I think I may have found the problem-

Under the valve retaining washer according to the diagram there should be a heat washer of some kind, this wasn't fitted so I am thinking that the bottom retainer was sitting staight onto the head and blocking the drain hole.
Click to expand...


Only some were fitted with insulating washers. Check your valve spring installed height. Lack of a washer will not block the return hole. Jim
 
So is it correct that the oil "pools" up in the inlet side and not the exhaust side ?????

And.... on investigation after running, 20-30 minutes later or is it a day after, there is STILL oil pooled in the inlet valve chamber ?????

And how long does it take for the oil pool to dissapear or drain ????
 
It pools on the inlet side, and it takes about 2 hours to drain, it fills it right up as you can see the level on the inspection cover, there is no blockage in the hole all the way through, thats why I wondered if it was the washer thing restricting it a bit
 
IMO, ............ If it takes 2 hours to drain, "which means it does drain although slowly"............

Like it or not, there is a blockage, restriction or at least something inhibiting the return flow of oil to the sump......... Its pretty simple. Please try to deal with one issue at a time.............. firstly from your original post, the oil is not returning to the sump... IMO, its not valve spring height (sorry Jim), not valve stem rubbers, not oil pressure, not rocker spindle, and riding it wont help (sorry Rohan).

Oil is not returning to the sump as would be expected, .. is the real issue...........

Even if you stuck a piece of 12g wire through the drains to the sump it would drain in minutes.. 2hrs to drain 70mml of oil, you only got a .020 or less return orrifice..

It has a blockage !!!!!!!! and you will find it........
 
You may have an unusual situation below the valve spring. For a test you could put a pool of oil in the intake valve area and then pry up on the lower spring retainer. See if the pool flows down as it should. If it does, you need to change one of the geometrys to allow the oil to pass down.
Just a desperate guess.
Jaydee
 
olChris said:
IMO, ............ If it takes 2 hours to drain, "which means it does drain although slowly"............

Like it or not, there is a blockage, restriction or at least something inhibiting the return flow of oil to the sump......... Its pretty simple. Please try to deal with one issue at a time.............. firstly from your original post, the oil is not returning to the sump... IMO, its not valve spring height (sorry Jim), not valve stem rubbers, not oil pressure, not rocker spindle, and riding it wont help (sorry Rohan).

Oil is not returning to the sump as would be expected, .. is the real issue...........

Even if you stuck a piece of 12g wire through the drains to the sump it would drain in minutes.. 2hrs to drain 70mml of oil, you only got a .020 or less return orrifice..

It has a blockage !!!!!!!! and you will find it........
Click to expand...

I agree, there is a blockage if the oil is not draining. Installing an insulating washer will not improve the drainage unless something is machined funny. Probably sealant at the head or base gasket is blocking the drain passage.
When I said check the spring installed height I meant you would not want to arbitrarily install insulating washers without checking the spring height.
Before you will be able to end the oil consumption/smoking completely you will still need to install valve stem seals. Jim
 
comnoz said:
olChris said:
IMO, ............ If it takes 2 hours to drain, "which means it does drain although slowly"............

Like it or not, there is a blockage, restriction or at least something inhibiting the return flow of oil to the sump......... Its pretty simple. Please try to deal with one issue at a time.............. firstly from your original post, the oil is not returning to the sump... IMO, its not valve spring height (sorry Jim), not valve stem rubbers, not oil pressure, not rocker spindle, and riding it wont help (sorry Rohan).

Oil is not returning to the sump as would be expected, .. is the real issue...........

Even if you stuck a piece of 12g wire through the drains to the sump it would drain in minutes.. 2hrs to drain 70mml of oil, you only got a .020 or less return orrifice..

It has a blockage !!!!!!!! and you will find it........
Click to expand...

I agree, there is a blockage if the oil is not draining. Installing an insulating washer will not improve the drainage unless something is machined funny. Probably sealant at the head or base gasket is blocking the drain passage.
When I said check the spring installed height I meant you would not want to arbitrarily install insulating washers without checking the spring height.
Before you will be able to end the oil consumption/smoking completely you will still need to install valve stem seals. Jim
Click to expand...

Another vote for a potential blockage. I found my head was partially blocked with head gasket material that had presumably been carelessly scraped off by a PO.
 
Its been a while now, and I am not really that much further on.

To date

I have replaced the inlet valves, exhaust valves, inlet guides with the later seal type and fitted seals, replaced the piston rings for some new ones just incase.

And Still

The right hand cylinder seems to smoke, more like steam which does dissapear when reved but instantly returns on tickover.

I have been told by someone that if the pressure release valve is too weak then the oil bypasses into the timing cover and can make the right side smoke almost like its wet sumping while running, oil is returning to the tank but iit would seem not fast enough, because of the extra oil entering the crank case.

Could this be correct?

And to add the return passage is clear and not obstructed
 
bigmike76 said:
Its been a while now, and I am not really that much further on.
And Still The right hand cylinder seems to smoke, more like steam which does dissapear when reved but instantly returns on tickover.
Click to expand...

I have not followed all of this thread, but if you are getting WHITE smoke out of cylinder, that is indicative of oil vaporising not burning - in the exhaust port. The chief cause could be a score in the exhaust valve guide bore.
 
I would have to agree with ML. I think the problem is still in the head.
You can get white smoke with oil in the intake also at idle speed. The oil can pass through the cylinder pretty much unburned at idle so I would be looking for a leak into either the exhaust or intake. Scored guide hole, crack or pore in the casting.
Usually you can see oil running down the guide by looking into the port on a warmed up motor. Jim
 
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