Middle gear oil pre-fill procedure?

I'm about to put my shifter cover back on the bike and I'm wondering if it's necessary or recommended to pre-fill that middle gear oil "reservoir."

 

Hi, isn't that all one cavity? As in, it is not separate from the 'main' oil volume? Many of us do not even drain from the middle gear oil plug just to avoid the high risk of that little plug breaking off. The volume of oil there is not enough to matter when changing oil so I can't imagine it needs to be pre-filled in your situation.

Someone can correct me if I'm wrong.

 

It fills itself when the engine is running.

Drain all your oil

 

Unnecessarily changing the Oil in the Middle Gear Cavity involves removing a Plug that is prone to Self Destruction.

The associated danger along with the EXTREMELY Labor Intensive Repair Procedures necessary to recover from the Plug being damaged is good enough reason to leave that Plug alone.

The Site does not recommend removal of the Middle Gear Drain Plug.

You do so at your own risk.

 

Good info. Thanks. Are you talking about the rubber plug inside the cover or the drain screw under the case? I did not touch the plug but I have already removed and replaced the middle gear drain screw without incident, so I guess I was fortunate.

The reason I asked is that this part of the middle gear housing is clearly designed to retain some oil, presumably for startup. Just wanted to make sure that it would refill quickly enough so as not to cause any damage if it was dry when I crank it over.

 

The almost inaccessible 10 MM bolt is not to be touched.
The service manuals instruct us to drain the cavity - we at XJBikes advise against it. But since you broke yours loose, you are "safe".

 

yeah well you have to check the oil level anyway after you start it for 5 mins. is the 'middle gear' reffering to tranny? if so you wouldn't have had to worry about a 'dry start' cause you'd start it for a few mins, shut it, let sit 5 mins, check level, all without riding it. Don't forget about when motors are built and started for the first time and after rebuilds, it's just a finger coat of oil on the parts, basically the same amount of oil left on the parts after the motor is shut. I used to think like that but then I started rebuilding my single cylinder race motors all the time and realized...

 

Under the circumstances; it's best left alone.
What is most important is one's awareness of the Caveat.

IF you do attempt to Drain the Middle Gear Cavity, ...
The Drain Plug Might Break.

IF you Break the Middle Gear Drain Plug it will take many hours of hard work to recover from the damage.

Those who have broken the Plug have had to:
Pull the Engine.
Or.
Do all the grunt work necessary to gain access to the Plug by flipping the Bike over upside-down.

 

This is a good argument for "assembly lube."

Also, a somewhat obscure but important point: The factory books mention that a specified amount of oil needs to be added to the FILTER HOUSING on a freshly-rebuilt XJ motor, to "prime" the lubrication system. I don't recall seeing this in the Haynes or Clymer books.

If you're really concerned about the components that possibly pick up oil from the middle gear housing, I'm sure it wouldn't hurt to dump a few tablespoons of clean oil in there. I doubt it's really necessary though.

 

Thanks for all of the input!