Oil leak from oil tank filler cap

[stevewhitt]

Hi All
First time this has happened, after a run, oil running down the outside of the oil tank, escaping from filler cap.

Any ideas anyone please?

Cheers

Steve W

[dave.owen]

Too much oil in tank

[stevewhitt]

Possible, but its only 1/2 full and did not happen last week on a similar run. I am wondering though whether I did not fully tighten the filler cap.

Does the oil level increase in the tank when running?

[Simon.Gardiner]

Assuming it is actually coming up past the cap, push a big 'O'-ring up to the rim of the cap so it seals on that when it's screwed down (it's what I've had to do, been working fine for a long time now and it's nice and easy to do!)

SG

[simon.holyfield]

Is the top of the filler neck flat and level? Is the thread good enough for the cap to screw down all the way to the seal?

I've repaired two filler necks on my four Ariels, so on that basis I think they get dropped quite frequently!

[stevewhitt]

Thats a good thought. In fact, it has a wonky thread because when I screw down the cap, it is not running true, and therefore possible not seating correctly on the sealing washer.

My concern was that pressure was building in the tank (for a reason I didn't understand)!

I am less concerned now about the leak. The bike (and I) are off to Normandy for the D-Day celebrations at the start June and this was concerning me.

Thanks everyone for your help.

[Simon.Gardiner]

My concern was that pressure was building in the tank (for a reason I didn't understand)!

There's a breather hole in the middle of the cap, top and bottom - might be worth checking that you can blow through them....
Well done on taking the bike off to Normandy!

SG

[nevhunter]

The scavenge part of the pump has much more volume than the delivery part,so if it's not vented, pressure will build up in the tank. Don't over fill and rough roads may make the oil splash around in the tank . Hot oil is thinner but the W/NG oil never gets very hot. Nev