2007 FLHX - When I changed my primary oil, I removed the o-ring type gasket and replaced it with the flat type gasket. The flat gasket LEAKED, so I removed the derby cover and reinstalled the o-ring gasket along WITH the flat gasket. The flat gasket's inside dimension is larger than the recess of where the o-ring gasket sits. The leak has stopped!

When I did a search for this topic, I found nothing, so I may possibly be the ONLY person using this method of added protection.

 

That is not added protection, it is a waste, as well as a point of potential failure, as now neither gasket can seal as designed.

 

Did you torque the derby cover screws in the correct order to the proper torque?

Doesn't sound right that the flat gasket did not fit properly. Was it an OEM derby cover? Was it an HD gasket? If yes on both, it should fit properly.

 

If I had the o-ring I wouldn't bother with the gasket. It's better unless u pinch it like I did the first time I changed fluid & all Harley had was the gasket. It's been off & on a few times with no leaks.

 

I used the stagger torque procedure. The cover is OEM. The flat gasket fit, it just leaked slightly.

 

Make sure the cover is not warped by placing on a flat surface. Otherwise the o-ring will work fine alone, in fact I have re-used mine several times with no problem. Just have to make double sure its fully in the groove before installing, I have to hold part of it with my finger as I slip the cover on. Harley has an oil change gasket kit that is pretty cheap and has all the o-rings in it. The gasket is pretty useless.

 

The next time I have the cover off I will check it for warpage. I always reinstall the cover in the same orientation as it was removed, just in case it does have an issue. If it does not leak, I'll leave both gaskets installed for the 2500 mile oil change duration.

 

The flat gasket is not for the stock OEM derby cover. It's for the derby covers you get out of the catalog that DO NOT have the groove.

Get back in there and take the flat gasket out. Use the rubber O-Ring style only. That's what you use with the Stock derby cover...

 

oops!

 

It happens. I've done it.