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Public Forums => ST1100 Archive of Wisdom => Topic started by: KoTAOW on December 30, 2007, 05:02:28 PM

Title: Ignition Switch Tune-Up ( ST1100 ) *
Post by: KoTAOW on December 30, 2007, 05:02:28 PM
(original post here: Mike Martin's ST1100 Maintanance Tips (

Ignition Switch Tune-Up ( ST1100 )

A number of people have experienced intermittent operation of the ignition switch. Sometimes switching on and off numerous times can get things going, for a while anyway. Some have sprayed contact cleaner into the switch, and that helps for a bit longer. But it's better to clean out that old dried-up grease, polish the contacts, and reassemble the switch to achieve the confidence that you won't be let down on the road.

I cleaned my ignition switch contacts several years ago. But with my faulty memory, and the fact that I didn't take any pictures, I was at a loss to be of much help to someone with the switch problem. So I decided to do it again, this time taking photos to document the operation.

Warning: My bike is a 1991 model. I cannot say whether or not Honda changed the switch design for later models. So don't assume that your switch is identical to mine.

The first time I performed the operation in the driveway. I was adjusting my steering bearings, and had the handlebars with the fork top bridge laying on a towel protecting the top shelter. Seeing the three screws holding the black cap to the bottom of the ignition switch, I decided to open the switch and clean it out. So I removed the screws and CAREFULLY opened the electrical portion of the switch, hoping that I wouldn't lose any of the internal parts.

NOW for an important message: DO NOT DO WHAT I DID. If something goes SPROING -- TINK -- TINK -- TINK -- TINK -- and you lose one of the little copper contacts or one of the little springs, you're going to be very sad or really pi$$ed!. Remove the two Torx head bolts attaching the ignition switch assembly to the underside of the fork top bridge. Then locate the rectangular white plastic multi-pin connector at the end of the wiring harness from the ignition switch and disconnect it from the bike. The harness is 16 inches or so long, and the connector will be found under the air cleaner housing, just behind the steering head. You'll have to remove a plastic air deflector just inboard of the radiator cap, and open a plastic wire clamp in the same area in order to free the switch harness from the bike. Then take the switch somewhere besides the driveway in order to disassemble it. Work on a clean table with a towel or some such on it to catch any part that may come falling out. Maybe you want to do the work with the switch in a box or tub for more insurance. Don't say I didn't warn you. Luckily, nothing bad happened in my case. But I didn't risk disaster a second time!

Inside the switch are a number of contacts. Some rotate with the key, and some are stationary, fixed in the portion of the switch that is attached to the wiring harness. The moving contacts are spring loaded, and there is some sort of grease inside the area. I think the problems that arise with the switch are primarily caused by the grease drying up over time.

So the object is to clean out all the old grease with a solvent like denatured alcohol or contact cleaner or WD-40, apply some silicone grease, and reassemble the switch. (I wouldn't recommend a harsh solvent like carb choke cleaner or brake cleaner, because of their unknown effect on the plastic parts.) You should use a Scotch-Brite pad to polish the contact surfaces as well.

I've created a photo album* illustrating the operation. Here's the album (*. Click on the first thumbnail, and you'll find captioning to go along with the photo. On the left are navigation buttons.

I hope this information is helpful to you.

* album photos and captions reproduced below

( - ST1100/Ignition Switch Tune-up - ST1100/01_connectors.jpg)

The white connector towards the lower right side is the one from the ignition switch. I found the terminals had a bit of corrosion on them, so I sprayed contact cleaner on them before I reassembled the connector. While I was at it, I did the same for the other three connectors in the metal plate. I had to remove the plate mounting bolt and lift the plate in order to be able to release the latches and unplug the connectors. See, a job always is a little bigger than you anticipate, isn't it?

( - ST1100/Ignition Switch Tune-up - ST1100/02_loosening torx.jpg)
I needed two six-inch extensions and a T40 Torx bit to unfasten the ignition switch from the fork top bridge. The bolts weren't easy to turn. I had to straddle the front tire to keep the wheel pointed straight ahead.

( - ST1100/Ignition Switch Tune-up - ST1100/03_torx bolts.jpg)
The Torx bolts had some white corrosion products in the threads near the bolt heads. It's been cleaned away with a wire brush in this picture. Also seen in the threads was a brittle yellow substance which fell off when I cleaned the bolts. I decided this substance was a thread locking compound (which explains why the bolts had so much drag when I removed them), so used some Loctite when I re-installed the switch.

( - ST1100/Ignition Switch Tune-up - ST1100/04_cap removed.jpg)
At this point you should be working in a safe area to save yourself grief from losing small parts. I used a copier paper box lid this time. See the small rectangular hole in the side of the switch? The black plastic cap has protrusions (almost impossible to see in the photo) which latch into two of these holes. Press a screwdriver tip through the holes to release the two latch.

( - ST1100/Ignition Switch Tune-up - ST1100/05_dirty switch.jpg)
With the cap removed, you can pull the switch parts out of the metal ignition lock assembly. In this photo I've removed the white plastic rotating part of the switch from the black stationary part by gently prying between them with a screwdriver. The dark protruding portion of the white part snaps into a hole in the black part. (A later photo shows what holds them snapped together.) The grease has dried out and discolored somewhat, but this switch was still operating just fine. Note that the springs beneath the copper contacts in the rotating part are not so long as to shoot parts across the room. Each of the contacts has two prongs which fit into recesses in the plastic part.

( - ST1100/Ignition Switch Tune-up - ST1100/06_rotating portion.jpg)
One of the movable contacts has been removed. There are two tangs on the copper contact which locate into holes in the plastic piece. One tang is wider than the other, and you can see the matching holes in the plastic part either side of the spring.

(continued in part two below)
Title: Re: ST1100 Ignition Switch Tune-Up
Post by: KoTAOW on December 30, 2007, 05:09:04 PM

( - ST1100/Ignition Switch Tune-up - ST1100/07_detail view.jpg)
The white plastic part has been cleaned. See the raised ring around the tip of the central protrusion? This causes this part to latch into the hole in the center of the black part.

( - ST1100/Ignition Switch Tune-up - ST1100/08_clean parts.jpg)
Everything is cleaned up and is ready for lubricant and reassembly. The copper contact surfaces were rubbed with a fine Scotchbrite pad.

( - ST1100/Ignition Switch Tune-up - ST1100/09_clean detail.jpg)
The white part is flipped over in this view to show the detent balls. It's important to note that the metal lug that engages with this part to rotate it when the key is turned is not four-way symmetrical. One of the narrow edges is narrower than the opposite one, and the hole is pear-shaped. If you don't engage it properly, the switch won't go back together. It's easier to see this before you grease things up. DAMHIK!

( - ST1100/Ignition Switch Tune-up - ST1100/10_lubed.jpg)
Silicone lube has been applied to all the internal parts. I essentially filled in the detents and coated the rest of the inside of the metal body. A layer was applied across the black part where the stationary contacts reside. The white part was coated, including the protrusion (between the copper contacts) which mates with the black part, as well as the recess on the other side for the metal lug.

( - ST1100/Ignition Switch Tune-up - ST1100/11_partly assembled.jpg)
The white part has been assembled into the metal body. If the aforemention lug and recess aren't properly mated, the white part will be hanging out of the metal body a bit. Properly installed, the entire piece is within the metal cavity. The black part gets pressed into location, after which the black plastic cap gets snapped into place. It takes a good bit of force to snap the cap on. You don't need to hammer it or anything, just press it in with your hand. Reinstall the three small screws to secure the cap. Now you can put your bike back together again. As soon as you get the switch installed and connected, make sure your bike will start. Don't wait until after you've installed all the tupperware. I hope it went smoothly for you!