Houston we have problem

[PX207]

Morning all, I'm after some help with an issue that seems to be traveling!

I've been using my 54 G3LS for daily 6 mile commute for the last 3 weeks. On on arriving to work last week I noticed that oil was leaking from the gauze filter cap, and not just a dribble. So I gave it a nip up before my ride home, hoping that was the issue, but it didn't! So I replaced the non-standard o-ring on the filter cap for the correct cork washer. I then took it for a short ride and to my dismay it started to leak, profusely, from the square cover above the inlet and return pipes on the engine block.

Am I right in thinking I have a blockage somewhere! And now the oil tank has an air-tight seal the issue has moved to this next weak link? Oil was returning to the tank, although it was weak but steady flow.

Thanks in advance Paul

[clive]

I wonder if you have recently changed the in tank oil filter? There were some dodgy ones about which had the filter material turned too far, so blocking the top holefor the oil to return to the main part of the tank. Perhaps by sealing the oil filter cover you have moved the excess pressure back to the oil pump cover (the part you described).
When i had this problem the excess pressure blew the return pipe off the bottom of the oil tank.
Oil flow to the tank on the singles is intermittent and not very strong at the best of times. At a fast tickover it should dribble out for a bit then stop before restarting once the sump has been cleared. This is because the pump has more capacity for return than supply (or it would tend to wet sump). If the filter was over pressuring the system you might get a continuous flow.
If you have not recently changed the filter it is unlikely a blocked correct filter would cause these symptoms as there is a pressure relief valve atop the filter.

[SPRIDDLER]

I wonder if you have recently changed the in tank oil filter? There were some dodgy ones about which had the filter material turned too far, so blocking the top holefor the oil to return to the main part of the tank.

My thinking too, Clive.

Filter oil faulty.jpg

Club spares filter........

Filter oil Correct.jpg

Have you recently topped up (overfilled) the oil tank? After the bike has been standing unused for a while some of the oil collects in the crankcase which is subsequently returned to the tank when you start up, therefore it is in addition to any oil that you add to the tank .

[PX207]

I did a complete oil change six months ago, I'll have to check the invoice but I'm sure the filter was a club spares item. But it looks similar to Spriddlers first picture.

Thanks Paul

[SPRIDDLER]

I then took it for a short ride and to my dismay it started to leak, profusely, from the square cover above the inlet and return pipes on the engine block.

For the pump to function efficiently the square plate needs to be an airtight (oil tight) seal to the c/case. Although I can't visualise how a leak there would cause oil to exit the filter housing cap it's worth checking (gently) that the 4 screws in that plate are secure. They are not very accessible and be very careful because by over tightening those steel screws the fine threads in the alloy c/case are easily stripped which can only be resolved by a total engine strip down.

Oil pump action..gif

[PX207]

Spriddler, many thanks for the brilliant animation of how it all works.

I've just checked my invoices and the filter was an AMC spares part, hopefully the photo will work:

What do you think?

Regards Paul

[g80csp11]

was the metal end plate and spring correctly fitted under the chrome cap . i think thats only a bypass if the filter is blocked
still sounds like something under the cork , no other way it could leak

[SPRIDDLER]

I've just checked my invoices and the filter was an AMC spares part, hopefully the photo will work:

What do you think?

The turnover at the left end does look a bit long. Ideally the felt needs trimming back if that can be done without cutting the stitching although it seems strange that it has taken 6 months to show up.

If that doesn't work..........Purists should look away now.............As a quick check I'd remove the filter and ride the bike without it for a mile or two and see if it cures the problem.

[PX207]

If that doesn't work..........Purists should look away now.............As a quick check I'd remove the filter and ride the bike without it for a few miles and see if it cures the problem.

That was my next move! Is there a gasket for the square end plate, I can't see one on the spares website?

[SPRIDDLER]

If that doesn't work..........Purists should look away now.............As a quick check I'd remove the filter and ride the bike without it for a few miles and see if it cures the problem.

That was my next move! Is there a gasket for the square end plate, I can't see one on the spares website?

Yes, paper gaskets for both end plates. (The forward end plate gasket must be fitted correctly to allow oil to exit via the external pipe to the rocker box). To be honest I wouldn't mess with the end plates until checking for leaks after a ride without the filter.

I think it's this but no photo shown........

https://www.amoc-parts.com//store/comer ... duct=20818

The felt at the r/h end looks a bit manky........

Oil filter felt 2.jpg