© 2022 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.

Clean K75/K100 Ignition Switch

If your K75 or 2 valve K100 cuts out mysteriously then it is not unknown for this to be caused by a dirty ignition switch. This page describes how to remove, disassemble and clean the contacts of the ignition switch.

It's best to do this on the bench, not on the bike, because there are tiny parts and springs to lose.


1) From the top, pry off the plastic ring that surrounds the ignition switch. You can do this with your fingernails.


2) You will then see a rectangular slot on each side of the ignition switch. Place a small screwdriver or other tool into each slot to depress the plastic tangs that hold the ignition switch in place. You should then be able to push the ignition switch down.



3) Removing the two bolts that hold the dash pad to the upper fork tree will make it easier to get the switch all of the way out of the dash pad.


4) Remove or pull back the gas tank in order to follow the ignition switch wiring to its connector and disconnect it.


Disassemble, Clean and Lubricate:

5) Wiggle off the plastic protective cap from the bottom of the switch.


6) Inspect the soldering at the terminals to ensure that the wires are all well connected.

Wires connect to:

Red 12V+ in from battery      
Green 12V+ out to load shed relay, etc…  
Gray 12V+ out to Fuse 2 (Parking light & BMU to tail light)
Gray/Blue 12V+ out to Cluster & add'l instrument backlighting


7) Test the switch with a multimeter. Terminal continuity for each switch position:

Off Nothing  
Position 1(park) Red-Gray
Position 2 (on) Red-Green


8) Locate the set screw covered in red paint.

Pick out the red paint - being sure to clean the screwdriver slot out well.

Use a small regular screwdriver (I used a 2mm screwdriver) to loosen the set screw. You do not need to completely remove the set screw. Just back it out 4 or 5 turns so that the white switch subassembly comes out of the switch body.


9) Take the switch subassembly apart. There's a small black tang on each side of the switch.

Use a small screwdriver at each tang to pop the white top of the switch off of the black bottom.

There are four tiny springs in the white top part. Make sure they are in place when you reassemble the switch.


10) Clean the two metal parts that are now loose, the "tepee" part and the crossbar part. Then put them back into the black body of the switch subassembly.


11) Using your favorite lubricant, (I use aerosol  spray silicone.) lubricate both the black bottom parts shown above and also the part that turns in the white top part.



12) Making sure that they are aligned to meet up, clip the white part and black part back together.


13) Put the switch subassembly back into the bottom of the switch body and tighten the set screw.

Align the hole in the side of the switch subassembly with the set screw in the switch body when reassembling.

If the switch subassembly has turned during servicing then you may need to turn it a little so that it aligns with post in the switch body. You can use a large screwdriver to do this.


14) Once you have the switch back together, test for correct continuity for each switch position.

Off Nothing  
Position 1(park) Red-Gray
Position 2 (on) Red-Green


15) Slide the protective cap back on the bottom of the switch.

Replace Ignition Switch:

If you find that your ignition switch is beyond repair then be careful when buying a replacement ignition switch. 1985 and earlier K100 ignition switches (part 61311459345) have a white five terminal connector while 86 and later K100 and all K75 ignition switches (part 61311459594) have a black four terminal connector.


© 2022 Drake Smith - Please do not use or reproduce this elsewhere.  Feel free to link to it though.