Hi Just took my 1969 A65 for its first run since the engine was re-built (by a competent mechanic who re-built an A65 for me with no worries a few years back). Weather was pretty hot, around 30 degrees Celsius. Running a little rough but thats to be expected first off. Initially oil pressure was around 60psi - great!. After around 15kms it dropped to pretty much zero, and the oil light came on. Nursed it home, plenty of oil in the tank and kicking it over with the plugs out I can see oil coming back into the tank.
I'd very much appreciate any advice on where I go from here.
Thanks in advance
John
If oil is returning to the tank when you kick the bike over unfortunately only shows there is some oil in the tank and the scavenge side of the oil pump is working - it doesn't guarantee that the feed side of the lubrication system is working.
It would be useful to clarify what you have fitted on the bike - do you have an oil pressure gauge fitted as well as the oil pressure switch? If a gauge is reading zero then either the pump has failed (highly unlikely) or there is a blockage in the feed to the pump or the NRV is stuck closed or there is a blockage after that. It's probably best to start on the feed side of the pump and check there's no blockage in the oil tank or feed pipe. After that, you might have to start delving inside the RHS of the engine.
Hi,
Did you check the oil pressure relief valve? Even if new it could be faulty. The initial 60 psi would have opened the oil pressure relief valve
quite bit and if it has stuck fully or partially open then the pump would struggle to maintain any pressure. When this valve is open the oil is vented in to the return side of the pump on later models, so oil will return to the tank as normal. As this will most certainly be the line of least resistance then there will be little or no oil pressure or flow to the bottom end.
Dave.
Thanks for the advice so far. I have an adapter which allows for takeoff to an oil pressure gauge and the usual sensor. I took the pressure relief valve off and the piston slides quite smoothly back and forth. Undid the sump plate and a very small amount of oil came out - maybe a dessert-spoon full. Kicked the bike over with the plugs out and no further oil came from the sump - is this an issue?
Normally, the oil from the oil pump has to travel through all the passageways to the big-end bearings before it then seeps back down into the sump. If there is a problem or blockage on the way, oil will may not get back to the sump.
If you take out the pressure relief valve and kick over the bike enough times, you should see oil being pumped into the valve compartment. If not, you may have one of the problems I previously listed. As said, I would start by making sure you haven't got a blockage from the tank to the outlet of the oil pipe union underneath the crankcase.
Unfortunately, if the blockage is not in the feed pipe, you are going to have to take off the timing covers to get at the pump, the feed NRV and the internal passageways.
Hi,
As Spaceman says try turning the engine over with the OPRV removed and see if oil gets through to there but it could be that there is some getting through but not enough to maintain the oil pressure. Also, with the plugs out, just kicking the engine over should create enough pressure to turn then oil light off.
Apologies if this is a stupid question but when you said, "I took the pressure relief valve off and the piston slides quite smoothly back and forth", there was spring in there as well wasn't there? The spring should be quite stiff.
As you check for blockages/restrictions check the size and quality of the oil pipe and for any tight turns that could kink when the pipe gets hot.
Dave.
My 1969 Lightning has the ball type OPRV. Although I have seen the piston type marketed as a drop-in replacement I am not fully convinced. Leakage in the threads is a possibility on both types and gets worse with hot oil of course.
Hi
Yes Dave, there is a spring, and if I take that and the piston out and kick the bike over only a small amount of oil comes out there. So I think I'll just bite the bullet and remove the necessary covers to see whats happening with the oil pump. Is removing and refitting the pump just a matter of undoing the bolts, or is there more to it, esp. when re-fitting it?
John
As said, I would do the simple check first and make sure oil flows freely from the oil tank when you remove the oil pipe union from the bottom of the crankcase - you need to use something to clamp the rubber pipe while attempting to do this or to drain the oil tank first before you remove the union so oil doesn't end up all over the floor.
However, you said that this engine had just been rebuilt by a competent mechanic - have you not been in contact with him to see what his view of this problem is? If, worst case, the engine has suffered internal damage to cause this problem then I personally would be looking to him to sort it out.
If you have to do the investigation yourself, removing the timing covers and oil pump is fairly straightforward. Fortunately, on this engine, there is a separate internal gearbox cover and so the gearbox does not need to be disturbed in this process.
Hi
I loosened the bolt holding the oil union allowing the union to drop down around 3 to 4 mm and oil flowed freely from it. Anything else I can check before removing the timing covers?
Are you sure the oil was flowing out of the tank and was not the small amount that would have been in the return pipe?
Assuming the feed pipe is ok and you don't get much oil in the pressure release valve cavity when you kick over the engine at least a dozen times then there is probably no other option but to delve inside the engine with the timing cover off.