1978 KZ1000 LTD - Loose Turn Signal Switch

Ever since I switched out and rewired my handlebars a while ago, my turn signal switch has gone wobbly. I can open up the casing and tighten the screw down to a good feel, but with use, the switch of course becomes loose. Tightening the screw too much makes it so the switch don't switch. Is the screw supposed to have some sort of spring washer to maintain tension? If it had one I probably lost it.

This is what I'm looking a inside the case:

 

It's coming loose because you are using a regular plain washer. Original washer was just a thin flexible wafer. This allowed tightening just under the screw head area to knob post, outside area of wafer flexed to allow movement. 

I just had a switch from a Kz650 apart.  IIRC, there is a small brass spacer/bushing that fits inside the lever’s pivot hole.  It’s ever so slightly thicker than the lever material so that you can snug down the screw but not clamp the lever.  You can confirm that it’s missing if you remove the screw and the hole through the lever is significantly larger than the screws OD.

Later, Doug

Ditto Streetfighter's comments. That brass collar IS the pivot tower in this application/switch type. If it's too thin you'll bind the selector lever when tightening screw. Selector should move freely with minimal slop.  I'm sure You already know this but here's a photo of the bits that make-up this area.   

Thanks for input guys, I'll take unscrew it and see if the brass collar is missing or needs to be replaced. 

And replace that  nasty screw while you have it apart