BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: LIONELSMITH on 01 Jun, 2026, 16:41

Title: A65 1967 how to replace oil tubing.
Post by: LIONELSMITH on 01 Jun, 2026, 16:41
AS I moved the A65 into the workshop it must have lost a pint of oil so I want to replace the pipes. I am fairly new to this bike. I can see the pipes coming out under the engine with the tubes and clamps fitted but it is tight and I don't' know whether I can get my fingers in to replace them. Equally at the oil tank end the feed tube is easy to get at, but the return is unreachable. The Haynes manual is useless.
If I remove the seat and back wheel, can I move the tank enough to replace the return pipe? Then I believe, I have read that the if unscrewed the oil three pipe feed under the engine, it will just pull out under the frame to replace that end.
Is this the way to tackle it or has someone that has done it got a better idea.
Thanks
Title: Re: A65 1967 how to replace oil tubing.
Post by: DMadigan on 01 Jun, 2026, 17:03
To remove the oil union at the engine you likely have to lift the engine slightly. The bolt is a little too long to clear the hole before hitting the frame.
Title: Re: A65 1967 how to replace oil tubing.
Post by: EDDIE SIMPSON on 01 Jun, 2026, 23:27
leave the union in place and slice off the old pipes with a stanley knife if you can undo the hose clips.
Title: Re: A65 1967 how to replace oil tubing.
Post by: DAVE BRADY on 02 Jun, 2026, 07:43
Hi,

As Eddie says slice off the old pipes then use them to get the right length for the new ones.
Put the new ones in some boiling water to get them more pliable. Put the clips on and a bit of oil in the end.  They will slide on the tubes nice and easy and once the clips are tightened and they have cooled they will be secure.

Dave.
Title: Re: A65 1967 how to replace oil tubing.
Post by: LIONELSMITH on 13 Jun, 2026, 17:42
Thanks guys
I've replaced the tubing but oil still flows out on starting. Its not the oil tank, hoses, all visible gaskets are dry, it is not the PRV and it is not the overflow. After the flood it is dripping from the oil level plug under the engine but that is the lowest point.
I think I have got to have the SRM built engine out but any tips on where to look for a serious leak would be much appreciated.
It's nearly summer, I've got three bikes and none are on the road.Thank heavens the A10 is nearly there!
Title: Re: A65 1967 how to replace oil tubing.
Post by: limeyrob on 13 Jun, 2026, 18:45
Is it the breather?  Its up above the drive sprocket
Title: Re: A65 1967 how to replace oil tubing.
Post by: DAVE BRADY on 13 Jun, 2026, 21:30
Hi,

This sounds like it could be coming from the breather as mentioned.
Is oil being returned to the tank? If not then a blocked return pipe/sump pick up. Remove the sump plate and poke a piece of wire. up in to the return pipe. There is a ball bearing in there that should very easily push up and drop down again.
Does it ease off with the engine still running?  If so then there could be lot of oil in the sump caused by 'wet sumping' and the pump has to return excess oil to the tank before it stops.  If not then it could be that the return pipe in the sump has come out and is allowing too much oil to sit in the sump before it can be pumped back to the tank.

Did you have the engine assembled by SRM for you to fit?

Dave.



 
Title: Re: A65 1967 how to replace oil tubing.
Post by: LIONELSMITH on 14 Jun, 2026, 15:18
Thanks again
I've been reading about the breather on an American site. They suggest putting compressed air down the camshaft aperture, whist rotating the engine. I'll try the sump pick up with wire/small engineering screwdriver to move/loosen the ball. Then dismantle the drive side and check/clear the breather hole and try some compressed air down the Camshaft aperture.
If it's the breather, which sounds likely, I've read a lot about engineering breather solutions. Would drilling out the breather hole not improve matters?
Title: Re: A65 1967 how to replace oil tubing.
Post by: limeyrob on 14 Jun, 2026, 15:42
Before you do anything I suggest taking it for a ride. Its quite possible there is nothing wrong, its just all a bit gummed up and the oil has drained to the sump.  A good run could fix everything.
Title: Re: A65 1967 how to replace oil tubing.
Post by: DAVE BRADY on 14 Jun, 2026, 17:14
Hi,

Engineered breather solutions should not be necessary and stripping the drive side will not give access to the breather outlet.  I do not know what they mean by 'compressed air down the camshaft aperture'.
The breather is timed on the drive side of the engine by a disc driven by the camshaft and would require an engine strip to sort it out but try the easy things first.
Did the engine not do this before moving it to workshop and how long ago did SRM build it?

Dave.
Title: Re: A65 1967 how to replace oil tubing.
Post by: LIONELSMITH on 22 Jun, 2026, 11:36
Thank again guys, sorry about the delay, I am just trying to get the A10 on the road at the same time.
I realised that I had a slight kink in the return tube so I tackled that first then went for the pick up tube. Firstly, I got more oil out of the sump than the oil tank! I gingerly poked my smallest Allen key up the tube with NO resistance, it kept going to the bend. Then the fun started. Whatever I did it would not move and would not come out. After lots of WD 40 and overnight it came out. The sump was dirty and it feels gritty up the pipe, still no ball I can detect. Does the pipe come off? I think the A10 version is supposed to. I've put more WD40 up the pipe to clean it.
To answer Dave's question SRM rebuilt the engine in 2007 BUT the bike was not ridden until 2022 when sold.The buyer was more interested in Sunbeams and trips to Russia on his Virago then sold it to me in 2024. I've used it sparingly. Long story short, nearly new.
Limeyrob it was losing a lot of oil and I think enough on a ride to drain the tank, I now know most was in the sump.
What's next?
Title: Re: A65 1967 how to replace oil tubing.
Post by: limeyrob on 22 Jun, 2026, 11:58
Start the A65 and watch the return.  You should see solid oil flow almost immediately than bubbles after 30 secs to a minute.  If its doing that you have oil circulation so then its worth trying a short ride.
Title: Re: A65 1967 how to replace oil tubing.
Post by: DAVE BRADY on 22 Jun, 2026, 12:00
Hi,

The ball will offer no resistance unless it is stuck as there is not spring and relies on gravity to bring it back down. All it really does is keep oil in the return pipe and feed to the rockers.
The 'gritty up the pipe' is a worry and it may be best to remove the return pipe from the tank and wash it all out from the top down. Use something like brake cleaner as it has bit of pressure and as the ball is likely to drop, hold it up to allow everything to flush through. No amount of cleaning is too much.  It will need to get through the oil pump as well
It is possible that there is gritty bits in the rocker fed so flush that from top to bottom as well. If there is non in this feed it is probably going to be OK in the rocker shafts. It will be worth removing the filter from the oil tank to see what is in there. Clean out any old oil and sludge.
If it was me, I would clean it all out before starting it or going for a ride and perhaps even remove the oil pump to check for smooth operation.

Dave.
Title: Re: A65 1967 how to replace oil tubing.
Post by: LIONELSMITH on 22 Jun, 2026, 19:15
Dave. thanks for staying with this.
The tank filter looks new and when I last drained the new oil, the tank was clean. On the other hand, in the sump the filter was dirty and the SRM screw off sump plate had bits attached to the magnet and a few black deposits in the bottom.
However, I have found a problem. When I refilled the tank I had not expected so much oil in the sump. When drained I must have had 4 litres of oil in all. The pump is working as I am getting oil to the top end. I started and ran the bike, no oil leak, BUT I could not see oil returning to the tank.It must be a blockage on the return side. I will replace the rubber tube and external filter and try again.Getting closer!
Title: Re: A65 1967 how to replace oil tubing.
Post by: rhyatt on 22 Jun, 2026, 19:45
If you have emptied or drained the sump completely, there is nothing there for the scavenge side to scavenge and return to the oil tank.
Put a bit of oil in the sump , say a cupful , start the bike and run it for the pump to scavenge and check the return of this oil to the oil tank.
This will give the feed side a chance to supply the engine and this oil will dribble down and itself get scavenged , repeating the cycle
Title: Re: A65 1967 how to replace oil tubing.
Post by: limeyrob on 22 Jun, 2026, 20:50
Has it ever been OK since you owned it?  I ask because I once had a similar problem and it was an faulty oil pump.  It had been fitted with one of the gears missing!.  Unlikely in your case but if this failure to return persists it will be worth taking the pump off and checking the gasket, oil ways and anti sumping ballan and spring as its behind the pump 
Title: Re: A65 1967 how to replace oil tubing.
Post by: LIONELSMITH on 25 Jun, 2026, 10:57
Latest
I have re-routed the return oil pipe and am getting good oil return to the tank. Having solved that the oil is coming out of the rocker box union. The new pipe is a little tight on length now, so if I cannot re-route I will replace. I am using 1/4" tubing is that about right? I also intend to lift the rocker cover to see if there any blockages inside.
Hopefully, I can still avoid stripping the timing side.
Title: Re: A65 1967 how to replace oil tubing.
Post by: rhyatt on 25 Jun, 2026, 11:11
The rockers are fed from the return side pipe , the pipe that squirms in the oil tank.
This pipe has a T junction that takes some oil to the rockers.
Slacken the banjo nuts that hold the oil pipe to the rockers and see if you get oil weeping when the engine is running.
If so lock it up and forget it.
Title: Re: A65 1967 how to replace oil tubing.
Post by: Ian C on 25 Jun, 2026, 12:46
Quote from: rhyatt on 25 Jun, 2026, 11:11 Slacken the banjo nuts that hold the oil pipe to the rockers and see if you get oil weeping when the engine is running.
If so lock it up and forget it.

Not on any A65 I've dealt with  ;)
To Lionel.. The oil feed to the head for the rockers should have a drilling all way through to the pushrod tunnel with a split pin fitted to help regulate oil feed to rocker shafts.
Title: Re: A65 1967 how to replace oil tubing.
Post by: rhyatt on 25 Jun, 2026, 13:46
apologies, I was thinking of my C15 rocker feed