turn signal stem?

Stock B1 rear stalks are part of the tail light bracket and the signals just bolt on. So, I'm not sure what you've done back there.

The front stalks have that diamond shape portion that fits into grommets in the fork ears that have a diamond shaped center. So, if you are running stock fork ears, Z1 makes stalks in several lengths that will attach correctly. Z1 also sells the rubber grommets as part of a 900 kit. It's kind of pricey and comes with a bunch of bits that you won't need, but the grommets do exist.

...and, with a saw and a grinder, you can cut the stalks down to whatever length you like and still get a solid mount for the signal. I know, because I've done that.

Im asking electrically. I have the front signals off. I only want to run the rear blinker. I don't need to cover any holes I just to make functioning. The rear signal lights but doesn't flash.