TOPIC:

My bike originally did not have the button (assuming previous owner broke it or something) so I have purchased a new button and spring/contact assembly. My problem is the backing where the wires connect into and where you’d press the button into, is loose and wild inside, the top side has a plate with a groove that’ll hold it but then the bottom side will slide and shift back. Does anyone know how to get that bottom of that flat plastic nearly rectangle but to stay in place?

Find a used set up

Or buy a repop.
Steve
z1parts.net/switch-handlebar-kawasaki-z1-900-kz900-right-side/

There should be a ridge, either along each side or I think along the bottom. The flat piece has to fit behind that ridge.

hardrockminer is right.

There is a rib cast into the lower switch housing that retains the bottom of the stationary switch contact that has the two start switch wires soldered to it.

The rib is difficult to see in the pic because the spring is mostly blocking it.

The stationary switch is meant to be retained by that rib on the bottom and the retaining plate on top.

Good Ridin'
slmjim & Z1BEBE

This might vary between models, but on the KZ750 and KZ250 I have experience with, the starter button was held in a little metal cage with the button on one side, and the contact with the wires on the other.

From this (bad) image here you can see the cage and how it clips onto the contact with the wires. What's not shown in this picture is the spring and button - to install a new spring and button, you remove the cage, fit the spring and button (it goes into the hole on the left opposite the contact), and then clip the cage back on. That way the button, spring, and contact are all one unit.



If you don't have that little cage it will probably never work correctly (unless it's not supposed to have it on this model - I don't know). If that's the case, buy the reproduction control unit, that $50 will save you a lot of hassle.