07 Nightster.

Is it true, when changing the primary oil one can refill the case through the primary chain (little square polished) inspection cover?

Manual states to remove derby cover (requires O Ring and possible clutch adjustment and derby cover torx bolt issues/ replacements) and visually observe the oil level filling to base of the clutch.

Will it take 1 quart exactly or 8/10 of a quart?

Any issues if over filled (adding one quart to what ever amount remained in the case and ending up with say 12/10 of a quart in the case)?

 

You can fill it through the inspection cover and it's usually one quart exact, with that said it's probably better to pull the derby and visually observe the level as you fill it. A few folks on here do it both ways.

There was a thread on here a couple days ago where the OP had quite a few problems after over filling the transmission. It will cause problems with shifting if you over fill.

 

Or do what I did and use a measured container to know how much came out...32 ounces and then add same amount. I did the same with my oil change and was surprised to see only 3 quarts needed versus the 3.6 specified in the manual. Knowing your bike is very important...

 

That's all well and fine, if the oil level was topped up before draining. And, with the primary, how ya gonna know?? If only 1/2 quart comes out, that doesn't mean it won't need a full quart to be filled properly.

 

Yea, should have stated that I checked the levels too...duh! Sort of like guessing on a dipstick measurement instead of looking at it. Good point to make.

 

just drain and fill with one quart.... dun..