ET: Engine (Twin) Wet sumping

Robert Watson

Well Known and Active Forum User
VOC Member
Drain the oil! They just about all can do this if left to their own devices. Trying to stop the oil passing the pump is a real hit and miss proposition. I am not a believer in putting a tap on the pump suction line and even wiring it into an ignition shut off.
 

ClassicBiker

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Well I go out into the garage every so often open the big door and just run the motor up to temp. I'm sure someone will get on here and tell me how bad that is, but it gets me out into the garage and looking about it making everything else is alright. I run all the other bikes up to temp as well, along with the cars.
 

Mike 40M

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Can't answer specifically as I don't have a Vincent twin.
But six of my eight old british bikes wetsumps. The not wetsumping two don't have any oil in them.
I put recycled oven pans under them during winter and drain crankcases before first ride in spring.
 
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Monkeypants

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Non-VOC Member
If you drain the oil and it happens to be clean enough to go back in after winter, be sure to put it through a strainer as it goes back in. You would be amazed at the bits of road grit that drop into the drain bucket when draining the oil. This is after attempting to clean the engine before draining. I find these particles on the strainer cloth.

I have one twin with a ball valve shut off on the oil line, no electrical switch, it relies on a different type of ignition cutout.
It is the easiest of the bunch to live with, no wet sumping, no farting around draining, straining and refilling.
I found that letting the sumps all fill to the top over winter caused lots of messy leakage.
Bikes that stay dry during the riding season seem to squirt oil everywhere once that sump fills up during winter storage.

Glen
 

ray vinmad

VOC Drawings Manager
VOC Member
The problem is probably worse since the introduction of multigrade `thin' oils.
The oil pump must have a running clearance, even if it's only half a thou, gravity will push the oil through the pump, and thicker oils must be more reluctant to filter through.
If that half a thou was also a gap in the crankcase halves, the sumping would drain straight into the drip tray!
Either use the bike regularly, fit an anti sumping valve or drain the sump first every spring.
Ray
 

oexing

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VOC Member
Yes, monograde should help, but then you have to wait a while for the oil to warm up from startup till wanting higher revs. Another plus of monograde is it sticks to components longer when not using the bike like in wintertimes. Basically it might be good to have only mnimal oil level in the oil tank for faster warmup at each start. My guess the typical Vincent runs a bit cold most of the time regarding oil temperature ?

Vic
 

Michael Vane-Hunt

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VOC Member
20210605_145616.jpg
Oil from my sump on the twin after 20 months of not being run pretty much due to the BUG, or just maybe having a new Triumph toy to play with. I use VR1 20-50 oil, engine has 45,000 miles since rebuild by John McDougal.
 
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