A: Oil Pipework Return Oil Pressure High?

Bill Thomas

Well Known and Active Forum User
VOC Member
Looks like I will have to carry a bit of rubber oil pipe,
Something else to worry about !,
Need a bigger tank bag :D.
The Vincent oil pump does tend to work in fits and farts as normal,
There is never a stream of oil.
My oil returns to the tank OK, As I have said before, I check it before every ride.
 

davidd

Well Known and Active Forum User
VOC Member
Thanks folks for comments so far. All rocker gear clear. Can easily blow through from A58 to cylinder head return in oil tank, so I have no idea where any back pressure could come from. I do have chromed oil pipes which could well be more slippy than optimum... however no problems since 1974!.. also I checked... no rodents... so I cant understand why suddenly now... my next move is to clamp each end of the hose down tight with crappy jubilee clips... if I don't get an oil gush from elsewhere I will do a bit of ferrule crimping!

John,

I would guess that there was a restriction in the steel pipe that runs from the return up to the filler neck. I had the pulsating when a nylon ATD tooth came off and worked its way to the return. It was too large to go inside the pipe, but a bit of debris or gasket goo could have done so.

It sounds like it has been cleared, which is good. It is a shame that Vincent did not filter the oil return as it pumps a lot of debris back into the oil tank.

Oil Filters.jpg


I did this on the racer, but I had the room under the tank. The return line ran up to the filter and then the filtered oil came down to the return on the UFM. This has been done on some street bikes by mounting the filter on the RFM pivot (bottom side). It was done on a few Series A bikes for cooling, not filtering, but the filtering cannot hurt.

David
 

John Fewster

Forum User
Non-VOC Member
Think solution found. I have chromed oil pipes and also double capacity pump worm. Pressure, though low, is slightly higher on startup and just enough to blow off the un-crimped rubber section. Once it first happened I cleaned, degreased and hylomared but it still throbbed and popped off after couple seconds running. I just now cleaned off again and stuck on 2x unsightly jubilee clips... and problem solved! No idea why it was OK for over 40 years then suddenly popped? May have been temporary blockage in rocker returns but I found no evidence. Did see evidence of red Hermetite on the pipes before cleaning and refitting. This stuff sets bit firmer than Hylomar so probably held seal for longer on the slippery chrome tube. I will eventually remove the jubilee clips, roughen the chrome under the rubber pipe, revert to Hermetite and do proper s/s ferrules with crimping on just these 2 joints.
 
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