Baffled, confused and covered in oil!!!!!!

[Greybeard]

 

[muskrat]

G'day BB. 
It's gotta be the scavenge pipe, loose fit into the case 
A bit off left field. The rocker banjo's are the correct ones and not off a single. Singles have a larger hole. Too much could be going up there and overwhelming the scavenge side.
Cheers

[Swarfcut]

 This lubrication system depends on the balance between the rate of supply and the rate of return. With the scavenge side having the greater pumping capacity, the balance is in favour of the return.  Have we tried a pipe on the pickup pipe in a bowl to catch the crankcase drain down, motor running to observe the scavenge working?

 Otherwise the pump is delivering too much oil, somehow. Think of anti wet sump spring plug leaking, main bearing bush leak around the outside, or simply the PRV stuck open. I'm no hydraulic engineer, but  a high flow rate because of  low  resistance could be the answer. Big ends surviving on copious splash? If you're lucky enough to have a rubber join in the rocker line try pinching this off to restrict rocker feed as Musky's thought.

 Swarfy.

[chaterlea25]

Hi All,
I have had an experience where a needle roller converted A10 gave trouble by pissing oil out the breather,
Eventually I found a leak in the end feed to the crank,
For some unknown reason this must have sprayed oil at the timing gears????
That carried the oil up to the breather..
This is of no help to the question of the sump filling with oil though

John

[bikerboy]

It's gotta be the scavenge pipe, loose fit into the case

checked and its not worse luck

Have we tried a pipe on the pickup pipe in a bowl to catch the crankcase drain down, motor running to observe the scavenge working?

Yep scavenged perfectly

Think of anti wet sump spring plug leaking,

checked working perfectly no sign of wet sumping even if left for a month

or simply the PRV stuck open

have swapped that with my other a10 which worked perfectly with its own PRV and works perfectly with the one out of this bike.

Oh well engine strip I guess

[muskrat]

G'day BB.
Before you start pulling it down try cutting off the rocker feed as swarfy suggested.
The rocker feed is teed off the return line. If too much is going that way it would give the impression of too much feed to the motor and overwhelming the scavenge side with oil building up in the crankcase.
Cheers

[RDfella]

so fitted a new pump but cant put it back together until tomorrow when I get a gasket. If it still pumps out of the breather then its going to be another engine strip

Can't see it's an engine problem. Are you checking the sump for oil before each start? If there's half a pint in there it will chuck it out of the breather when you start. Some bikes don't wet sump. others do after a week or more, some after just a couple of days or so.
In the above quote, is that another pump fitted - and did you strip the previous one to check the internals?

[berger]

i removed the 5/16th bolt in my home made sump plug conversion many years ago and not a drop of oil came out untill i jumped on the kick start then loads came out. , maybe a vacuum was holding it in there,

[RDfella]

i removed the 5/16th bolt in my home made sump plug conversion many years ago and not a drop of oil came out untill i jumped on the kick start then loads came out. , maybe a vacuum was holding it in there,

Got caught out the same way - only I presumed the sump was empty and started up, dumping a quart of oil on the floor in seconds.....

[Swarfcut]

        As a suggestion before putting the motor under the spanner.

 Start it up, get the oil circulating, stop and let things settle. Sump plate off, let it drain down to ensure the crankcase is truly empty, sump plate back on. Disconnect  Rocker feed and  direct to the oil tank filler. Start up, and observe the oil return from rocker feed and the normal return flow. Ok, the rockers will be dry for a few moments of the test, but this would prove the scavenge works and the problem is oversupply to the crankcase rather than poor scavenge. Oiltank level should settle slightly, then remain constant.

  The ball valve for the anti wet sumping is sealing the oilway to the timing bush when the engine is not running. So sure, no wet sumping on standing. But behind the ball is the spring and its blanking plug so when oil pressure moves the ball, this pressure is also acting on the spring plug. So a leak here feeds directly into the crankcase, and will only be apparent with engine running, and with oil pressure in the gallery. Something else to check, but awkward to do in practice, oil pump off, pump some oil into the gallery  from a pressure type oil can and looking for rundown is one way.

Swarfy.

[bikerboy]

I have found the problem thank god even tho its major. Behind the oil pump gasket the crankcase has cracked at the top return hole. The scavenge is effectively pumping some back to the tank and some back thru the crack into the bottom of the timing case. I discovered it when I was trying to change the pump.

As a temp thing and more as a test than anything I cleaned it up last night and filled the crack in with chemical metal. Tested it all today and its fine nothing out of the breather at all. I did say right at the beginning of this "War and Peace" fault that the only thing not tested was the crankcases. The crack was not noticeable at first but I think repeated loosening and tightening of the pump has actually opened the crack up. Its still only hairline but its there and if I had not decided to change the gasket for one of the one piece SRM ones I would never have found it.

I daresay the chemical metal could be used to make a permanent repair but I have spare crankcases and wont be comfortable unless I change them. Shame now I need a new main bush and line reaming all over again

Still at least a very baffling question has been answered.

[muskrat]

G'day BB.
TFFT 
Sort of bitter sweet outcome. As the motor gets hot the crack would open up allowing more oil to pass.
Could you post a pic of it?
Cheers

[bikerboy]

Sort of bitter sweet outcome. As the motor gets hot the crack would open up allowing more oil to pass.

Firstly I have found it and thats the good thing. Bit upsetting that I need to strip and rebuild but it is what it is I am just thankful that I found it. I will try to post a pic when I have the crankcases apart but for some reason I have never had any joy posting pics here.

Thank you everybody for your patience with both myself and this damned problem. it has driven me to despair and I guess you have had more than enough of it as well :)

[muskrat]

G'day again BB.
email me any pics and I'll insert them.
Cheers

[RDfella]

Thank you everybody for your patience with both myself and this damned problem. it has driven me to despair and I guess you have had more than enough of it as well :)

It is when you despair that a forum like this one is invaluable. Been in that situation a couple of times myself.