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Starting the shadow after few months - Oil problem


Active Forum Website User
VOC Member
Hello everyone,

Weather is becoming better those last days and I decide to check the shadow before starting it after it has been not running for about 4 months.
After checking the oil in the UFM I realised that the UFM was totally empty. All the oil in it gone in the engine. Well, certainely after a long period, the oil stock in the UFM use to go in the engine ??
After that, I decided as I notice oil leaks from the kickstart cover to open it and it was full of oil !
I removed it and find that the oil came from the primary chain case cover, coming by the hole where the kickstart is fix.
I look out the primary chain cover, and it was full of oil !
How the oil from the engine can go in the primary chain cover ? It is normal ??

Many thanks ,

Tnecniv Edipar

Well Known and Active Forum Website User
VOC Member
The oil has drained past the valve in the main oil feed pipe that normally should prevent oil flow with the engine off. The oil fills the crankcase then flows into the primary case when the level in crankcase reaches a high enough level. Drain the crankcase and primary case and refill the oil tank /ufm with new oil. The only problem will be that the clutch will have become contaminated with oil and may require cleaning and degreasing.


Well Known and Active Forum Website User
VOC Member
There's a stop valve for when you disconnect the oil pipe as standard, but any anti sumping valve will be an aftermarket jobby..John


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VOC Member
Not that I have found.The extra length of the spigot that goes into the stop valve opens it and holds it open till you remove the oil pipe..If yours does not sump then your pump is in fine condition,or you use it enough not to notice which I suspect is more likely..My 1932 Sunbeam will fill the crankcase in 3 days,but if it is run every day then you don't notice it..John

John Appleton

Well Known and Active Forum Website User
VOC Member
Interesting , I thought that stop valve also worked as an anti wet sumping valve !

As John says, there is no anti sumping valve on a vin , unless fitted as an extra. The usual way oil flows back to the sump is either through the clearance between plunger and oil pump sleeve or, in rarer instances, between the outside of the sleeve and the parent bore of the crankcase.
We must assume in the case in question that there is no driveside mainshaft oil seal modification fitted. In this case the oil flows slowly back, as described above, until it reaches the level of the mainshafts. It then makes its way through the drive side oil scroll into the primary case and, if the wine bottle cork is missing from the left hand kickstart shaft tunnel, along said tunnel and into the kickstart cover and, usually, onto the floor.
If the two oil seals protecting the clutch are in good order there is a fair chance the clutch has survived without contamination. The advice about draining the various housings is sound, and the bike should run as well as it did at the end of last season, but the wise course is to keep the matter under observation to ensure the amount of flow back is acceptable.
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