I have a 2006 1200 custom and going to change the tranny fluid, and want to know if it's correct. I know there is a drain plug, I have the 1 quart that is GEAR & CHAINCASE LUBRICANT from HD. So I start the bike to warming temps, take the small inspection cover with the 2 screws, and drain the fluid.

I then change the o-ring and put the fluid back, and pour the fluid in that inspection hole, is this correct?

 

No. warm it up. Drain it. Unscrew the primary cover. Put drain plug back in. put one quart of fluid into the primary (get a funnel and just pour into the side). Screw primary cover back on. Done

 

This is what I do on mine, but I don't change the o-ring every time. When you drain it, once it stops flowing, you can stand the bike upright and get another ounce or so out. Don't forget to wipe off the drain plug, it is magnetic and will have fine powder-like metal shavings stuck to it.

Knights way works too, but removing the primary cover is crazy, pretty sure he means the derby cover. If you are not doing a clutch adjustment, the inspection cover is easier, if you do take that derby cover off, I'd change the screws to stainless socket heads with lock washers and ditch the torx.

 

Just to get your terminology straight, the Primary Cover has like a dozen bolts holding it on. Removing the primary cover exposes the primary chain and sprockets.
The Derby Cover is round and has 4-6 bolts (depending on the year) holding it on. Removing the Derby Cover exposes the clutch adjustment.
The Primary Chain Inspection Cover has 2 screws holding it on. It exposes a section of the primary chain for checking the chain adjustment.

For a simple primary oil fluid change, the only cover that needs to be removed is the Primary Chain Inspection Cover (2 screws).

 

Just remember, do not try to pour that 1/4 oil into the transmission, with the bike in the side stand, or you will experience a tiny oil tsunami. Ask me how I know

 

That's why it's easier and better just to refill the oil through the primary chain inspection cover instead of the derby cover, nothing can spill, even on the side stand.

 

Now I know.
I had that open since I had to adjust the clutch, and I did not think of the consequences.
I had the chain inspection cover open too, but the other hole was bigger

 

thank you. My manual says to take off clutch inspection cover/derby cover but now I know that wont be needed

 

However, if you are doing a tranny fluid change you should also adjust your clutch while you are there and your chain as well. This is all in the HD service manual. Just my 2Cents!!

 

Adjust your clutch and primary chain. I place a block under the kick stand and follow the factory service manual when adding the fluid to the trans.