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

[Rocket Racer]

Thanks for all your comments and help just to answer a few questions.

The cork washer on the end of the camshaft is fine and the breather peg is located.

It has no oil filter fitted, the return pipe has a simple T piece in that goes off to the rocker box just before it enters the tank. I think the rocker pipe blew off when I put my finger over the return hole hoping to encourage the oil to circulate.

I have, in my own mind,  put the problem purely down to the return system to the tank but I must admit it never occurred to me that the scavenge pipe could be cracked and if it is then that would explain everything. Sticky ball yes but I never thought about a crack.

With the plunger if my memory serves me rightly the scavenge pipe is actually bolted to the inside of the crankcase, I will have to hook out another set of cases and check. If it is then its an engine strip down for sure

Now correct me if I am wrong but if its not just the ball sticking, which I doubt I am quite thorough on a rebuild as a rule. That pipe returns directly to the back of the oil pump so removing the pump and putting an air line on it should expose a crack particularly if I wobble the pipe a bit as I blast air into it.

Looks like it could be another weekend spent on stripping and rebuilding again

I’ve heard of s/a bikes where the scavenge pipe had fallen off (or was missing) without causing symptoms of wet sumping, as the oil level just rises a bit to the level of the gallery in the case, I’m not sure if this is the case with the semi unit engines but I thought it worth mentioning, before you strip it down!

It does sound like the cases are filling with oil.

I had a puzzling oil supply issue with a Honda gb500 (no supply to head/cam), I eventually worked out what was going wrong by “experimenting” with pieces of tube and bottles to hold supply/return oil, this may be an option for you before you strip it down 

Edit...I just re read yr 1st post and oil was coming out of the head oil feed “fast” when you had the oil coming out the breather, no way it should ever be “fast” ....the oil supply to the valves on my bike is a dribble at best. That indicates the cause is probably a blockage (intermittent?) between the tee to the head and the hole in the tank pipe doesn’t it?

 I think Rocket Racer had this issue (during a rally) and the blockage was cleared quite easily.

Only just seen this post; I did have an intermittent oil return problem on my super rocket which seemed to be blockage related and only occured once to me then behaved. The present owner (with one in between) has replaced the original oil pump with an SRM one, had the return thoroughly cleaned and removed the oil filter on the return which was plumbed up via the tool box. That engine also has long had a bearing conversion with a centre feed. I believe its presently behaving again.

Cannot imagine the PRV likely to be related although the later A65 type plunger version far more reliable than the original ball bearing type.

[edboy]

the a65 also had an oil warning light which would be helpful as the oil is not going where it should and if low oil pressure, will knock out the mains.

[bikerboy]

I am going for the PRV out of desperation really I would not mind so much if the oil was not circulating but its returning perfectly with enough pressure that if I block the hole in the oil tank using my finger it blows the rocker feed pipe off.

The return to the tank is constant while normally it spits a bit as the return is more powerful than the feed, but the oil pump was on my other A10 and was only changed to fit a rev counter drive so in my eyes it cant be the pump.

The only bit of guesswork left for me now is the PRV not opening/closing at the correct pressure even tho it has a new ball and spring in it and appears to operate ok.

The one thing that keeps nagging at me is the scavenge (the crankcases) as these are the only parts that are untested by me as such. I bought them off ebay I think and maybe I missed damage to the scavenge pipe or something when I put it together.

It would not be so bad but the engine starts and runs perfectly and even the rocker box does not leak so stripping it down again will be a right pain

[berger]

do you mean you got the cases off ebay and didn't check your sucky tube? if so there may be an intermittent fault depending on revs and vibes and it could be pulling air at times and not oil when you are riding it and seem ok when its stood just a thought because I haven't got a clue really and weird things like that  happen, like two strokes increasing revs when they pull excess air from a joint and you spray joint with oil or something and find where its sucking air in. I will shut up now rambling again . time for bed said zeb

[muskrat]

G'day bb.
I was trying to think of a way to test the scavenge system for leaks.
Drop the sump plate and push the ball up the pipe a bit to drain any oil out. Remove the return line from the motor and with the plugs out kick her over till no oil comes out the pipe. Put rubber hose over the pipe and a finger over the scavenge pipe. Now suck on the hose and put tongue over the hole. See if it holds vacuum.
Or, put hose over scavenge pipe and block it. Then apply air pressure to the other hose and listen for any hissing. 20Lb pressure should be enough and be safe.
Cheers

[duTch]

 

.......Or, put hose over scavenge pipe and block it. Then apply air pressure to the other hose and listen for any hissing. 20Lb pressure should be enough and be safe.......

Fairly much how I tested mine at Larry build,  but figured the ball should block it anyway( guess a bit of hose will stop splatter?)

[muskrat]

G'day duTch.
I figured with a blocked hose it would eliminate the hiss coming from around the ball 
Cheers

[duTch]

 

...I figured with a blocked hose it would eliminate the hiss coming from around the ball  .....

Fair call- I remembered I did it all before i putt the pump on too, so less oth er places to leak from.... and at same time made sure the feed side was clean and ball and spring doing their stuff

[edboy]

hi bikerboy, i wonder if the crank gear is making good contact with the oil pump gear [ which do wear].is the crank washer missing , too much end float? if your problems started after swopping oil pumps i would go back to the old oil pump and test.

[Greybeard]

In case you don't know, the SRM PRV is a different design. It has a piston, rather than a ball. I think that Triumphs had that design. I fitted one to my bike. I do not know if that is a superior design.

https://shop.srmclassicbikes.com/product/stainless-steel-pressure-release-valve-bsatriumph-twins

[RDfella]

Is it possible for the timed breather to create an intermittent fault?

[chaterlea25]

Hi RD and All,

Is it possible for the timed breather to create an intermittent fault

If the driving peg was barely engaging the breather sleeve due to either a worn casing or the driving dog not positioned correctly in the gear then Maybe??

John

[clive1]

with all the investigations you have done yourself and the advice from the knowledgeable guys on here,
we often look for deep issues without always checking the simple things first
we all tend to think the worst when it is your own bike
is there a chance the flexi oil pipes are swapped over from their correct position
just a thought
but our sympathies are with you
and We will get it sorted between us

Clive1

[RDfella]

More thoughts. Seems it is intermittermently wet-sumping, causing the breather to throw out the contents of the sump. And do they!
I can think of two possibilities: the wire pin in the pickup pipe is missing, meaning the anti-drain ball can go right up and block the pipe, or the sump gauze is too fine and oil can't drain through it fast enough to get to the return suction pipe. Often wondered about the latter ever since I had a wet-sumping with oil pumping out via breather. I had already drained the sump (via the drain plug). Or so I thought. Actually I'd only drained a little and the rest was 'hiding' above the gauze, presumably held there by vacuum. I think most of the oil actually drains down through the hole the pickup pipe goes through rather than the gauze itself. My view is that the mesh supplied these days is a little too fine..

[JulianS]

Good point about mesh size.
 
There is an old Triumph service note which gives that as a possible cause.

Same note also says that a scavenge pipe end being too close to the sump bottom can also be a cause.