Can't see any ball bearing in the sump ball valve ( picture attached). Rupert Ratio tells me it falls under oil pressure & no spring involved. just probed with a spoke & couldn't feel anything after an 1 1/2".
Could the bearing just be further up ? didn't want to probe further in case I push it somewhere unhelpful.......if it's there that is.
Any advice on whats best to do ?
( tried blowing down the return pipe ! but air goes nowhere. Tried putting a pipe over the ball valve tube and sucking. air flows, but all I got was some more oil heading my way and no ball bearing)
I don't think the ball bearing can cause a problem if it fails to drop down. Its function is to stop a flow of oil back into the sump which happens when the ball falls down under gravity to block the exit from the pipe. As long as you are getting a normal flow of oil tank into the tank, then there's probably nothing to worry about. If you've got an airline, try blowing down the return line coming from the engine to see if it dislodges the ball bearing. I'm not even sure you can remove the scavenge pipe from the pump and so it's unlikely the ball bearing has been removed.
I Need to double check
I had original thought it was the tube on the right (towards front of bike) had the sump ball valve?
After staring at my 1965 manual and Rupert ratio I now think I was wrong and that the right/front pipe is the oil return from the pressure release valve.
a) So should the sump ball valve be the pipe on the left of my photo which appears to be the scavenge tube for the pump ( looks to me as illustrated in Rupert Ratio Illus 5.12b, pg 36)
There's no evidence of a ball bearing there. I can insert a bicycle cable end in 3" (full length of scavenge tube) before feeling what may be the gears rather than a bearing. I notice the end of the scavenge tube is threaded so it looks like a previous owner has removed or tried to remove it. I'm wondering whether that means the ball was lost in the process and whether the internal shape of the tube seat is knackered so wouldn't hold a bearing ( even if I was brave enough to try and remove it).
It's only the oil from the return tube presumably that would drain to the sump as a result ( i.e the tank won't empty when engine off), with the risk that the lower pump gears gears end up dry and produce too little suction on start-up to return oil to the tank.
b)But if that doesn't happen where does the oil go that is being pumped through the engine ? & once the sump is full ?
The advice provided on this forum was don't worry as long as the oil is returning to the tank.
c) So when I first start up the engine do I just have the oil cap off and keep my eye out that oil is flowing out of the return ?
d) If it happens then, can I be sure it'll carry on doing that once I put the cap back on !?
Yes - the scavenge pipe is on the LHS built into the oil pump.
All the scavenge valve does is to stop oil draining back into the sump from the return pipe to the tank - 50cc at most? You definitely, don't need to worry about the oil pump gears drying out. Even when dry, it'll still suck up oil from the sump once the engine starts to run.
If there is no ball bearing present in the scavenge pipe, all this means is that you have lost the NRV function which only comes into play when you turn the engine off - it won't affect what happens when the engine is running.
That said, I would be a bit concerned to know what has happened to the ball bearing. It's probably 3/16" in diameter but is it possible for this diameter of ball to have fallen out of the end of the scavenge tube?