No46
CB750 Member
I have 72 k2 that I ride as I am fixing it up. Today when I checked the oil it wa almost a qt. low. I put some in, but it came up when I ran the bike. Whats going on?
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Oil drains from res.
- Thread starter No46
- Start date
There is a valve in the oil pump that is leaking allowing the oil to drain back into the engine sump. Could be a piece of debris keeping it from sealing or the rubber seal on the valve could be damaged or too hard to seal. Unfortunately right now there is no replacement for the seal but I have heard rumors there will be a replacement available but I have no time line for it. How long does it take to drain down the qt? If it takes a couple of weeks I wouldn't worry about it but if it does it over night then you need to look into it.
It is normal for the oil to drain down into the sump when the bike sits. Its gravity. The oil tank is higher than the sump. You should always check the oil after the bike is well warmed up or you will think your oil is low and overfill. Have had many discussions about this on another well known board.
It should leak very little if any back to the sump if the valve is working correct. There is a valve in the oil pump that keeps oil from draining back to the sump from the tank, that is its purpose. Mine personally leaks about a cup into the sump after a month of sitting. Over time yes it will leak down some oil but it should not be a drastic drop.
No46
CB750 Member
Thank you. Could this ever lead to oil starvation, were the tank to drain down?
Yes if the tank drains empty do not start the bike, you will not be oiling the engine. If it drains a quart down you will be ok. Any more than a quart and I would drain the sump and add to the tank. Oil from the tank goes directly to the oil pump, I have seen them started with 2 quarts in the tank and that was just enough but I dont recommend.
