For me it was the rear diff.

If spinning now figureout if the plug has stripped threads or if the tool is spinning in the plug.
You will want the threads to be good if you have a choice.

 

To your question "Are front diff drain plugs supposed to be this annoying?", the short answer is "NO" but in real life they do tend to tax your patience.
I see that your ride is a 2014? is that right?, what did the fluid look like that came out? I try to change mine annually (last year I didn't because I only was able to put a couple hundred miles on it).
Like Ducvet said, hopefully if it got cross threaded, then only the threads on the drain plug got buggered up.

 

To your question "Are front diff drain plugs supposed to be this annoying?", the short answer is "NO" but in real life they do tend to tax your patience.
I see that your ride is a 2014? is that right?, what did the fluid look like that came out? I try to change mine annually (last year I didn't because I only was able to put a couple hundred miles on it).
Like Ducvet said, hopefully if it got cross threaded, then only the threads on the drain plub got buggered up.

Hey, the fluid looked like yellow. Nothing dark. I only changed it because i bought it used. I honestly don’t think it’s ever been changed. It has 4k km, and the gear oil looked terrible. Upon buying the bike the rear diff blew 2 days after buying it and only driving it around my driveway. Reason for it blowing: Rear diff had mud & insanely bad looking fluid, i got my buddy to rebuild it for me. I’ve just been doing all of the maintenance after that cause I don’t trust that it’s been maintained.

Anyways, I took it for a spin and the drain plug isn’t leaking whatsoever. Not sure what’s going on because it doesn’t want to tighten snug. It just keeps tightening and tightening. So I’ll probably leave it alone before I make it worse? Hopefully the threads in the diff aren’t messed up though. I’m not too experienced with fixing them.

 

Roger that. Hopefully the old owner was keeping up on the maintenance. Probably need to put it on your annual maintenance schedule.

The next time you remove it, do it gently, move it back and forth as you back it out, do that several times during the removal, you don't want to deal with damaged drain hole.

 

If its not tightening then you probably pulled the threads out of the aluminum. You can either install a helicoil or tap it to a different thread size.

 

Don't believe a Helicoil is an option due to being a NPT (tapered) thread.

 

Mine was a pipe (tapered ) thread iirc, might be easier to oversize.

 

Remember to take the fill plug out first, that way if you have an issue you don't have drained fluid and no way to refill it.

 

On my 400 the front was not NPT and was metric where the rear WAS NPT so there is a chance that his front will be able to get a thread repair.

 

You

I'm pretty sure the Allen heads are different as well . Front is metric and the rear is SAE.

 

100% true on mine.

NEVER guess though verify before you strip one.

 

Like a ford, Harley or many others today.

When in doubt stop and try the tool you are sure it could not be because some times it is....

 

I'm in pretty much the same situation and scouring the internet for answers. This was the first thread the had the same issue as me. My rear diff drain plug removed like they always do, with a little bit of force to beak loose. When I went to put it back in, it threads just fine but never stops tightening. I feel like I could spin it all the way into the case. I backed it out, made it flush with the case and I guess I'll wait and see if it leaks. It's a 2018 650. Just bought it used and wanted to change all the fluids.

 

How far past flush with ege case did it go ?
They typically sit about flush when tight.
Where was it when you removed it ?
Maybe the previous owner drove it in with a rattle gun and damaged it.