There seems to be a lot of trepidation involved when considering doing a rebuild of the right hand switch because we've all heard the horror stories about how there are these tiny little springs and things in there that, if you unleash them, will leap out at you and make off with the dog and in general create mayhem for everyone concerned. I'm here to tell you that it just ain't so. There
are some springs in there, true; four, to be exact, and they are tiny - not gonna lie to you. But with a little preparation and a few simple guidelines they can successfully be corralled; and in all of the switches I've torn apart and put back together, none of those pesky little springs have gone on to terrorize the neighborhood (that I am aware of).
Discussion and Configurations
This 3-way switch/throttle control assembly was used on a lot of old Hondas from the '60s and '70s with several different applications. It's the same one I had on my old '69 CL350, and I believe at that time it was used on most of the bikes up through the '750s; all of the CB500s used it (or a variation of it) prior to their evolution into the CB550. In this application, the starter switch consists of a stud and contact that simply grounds the starting circuit, while the 3-way light switch cycled between OFF and LO/HI beams. This lighting control was modified into a simple ON/OFF switch on most models in '74 when the HI\LO section migrated to the left handlebar, and was eventually eliminated altogether in '76.
The dimmer switch move to the left side control was a good one, IMHO, because I know from experience just how easy it was to overshoot the low beam slot when clicking off the high beams and end up turning the lights completely off. There was a little jog in the lever slot that was supposed to keep you from doing this, but it happened anyway (the definition of "thrill" can be experienced quite adequately when the lights go off while rounding an outside curve in the mountains at night in a snow storm). It was also a little easier to control the throttle if you weren't working the dimmer switch at the same time
These shots show a couple of steps in the evolution of the right switch upper housing. As mentioned above, many different types of Hondas used these controls - for instance, these in particular are left: '72 CB350; middle: '74 CB550; right '76 CB550K. Essentially, the first two are the same inside and out with the exception of the lever slots and the external markings. The housing on the far right came on the '76 models after the lighting switch was made obsolete, and it was redesigned to eliminate the detent and lever slots present on the older models
Here, you can see the lever slots and the changes made for the different applications
Design changes were made to the lower housing as well. When control for the lights was essentially moved to the starting circuit beginning with the '76 bikes ('75 for "F" models), it called for a larger and more complicated starter switch, and required that the lower shell be redesigned to accommodate it, as can be seen on the right. We'll cuss and discuss this switch when we cover the start button installation
All of these were anodized a nice, shiny black by Honda, with the control markings apparently molded (stamped? roll-engraved?) into the bodies. These marks were filled in with a flat International Orange paint that was applied by automated silkscreen... Testor's Model Master International Orange is a close match if you're rebuilding.
Although these controls have an outwardly similar appearance, they're actually each modified pretty specifically for their applications. That means that it's kind of difficult to use the '76 switch on a '74 bike, or a '71 K model switch on a '75 F bike (for instance) without making some fairly extensive modifications to the wiring harness including adding jumpers, splicing wires and other insults to the electrical system. While I've done it myself, it's a chore and it just isn't right no matter how well you do it. It's best to get the right switch for the right year and application, in my humble opinion.
Disassembly
We'll be working with a switch for the '74-'76 CB550K
(though other bikes shared this same control), but certain aspects will apply to other switches as well, and the differences will be indicated as I come across them. The kill switch info is common to all three, so there should be no ambiguities there. The headlight controls are very similar between the older OFF/LO/HI switch and this one; basically, there's just an extra wire on the contact board. It's the start button (as previously discussed) that makes the most dramatic changes, combining the headlight and starter controls in the post-'76 models, while changes in circuit design dictated modifications between the older switch and this '74 model. I'll dedicate some space to all of the differences when we get to the starter section.
Let's get on to the switch.
Here's how it looks spread-eagled and helpless. The left half houses the starter button, alignment pin and a loom clamp. On the right is the lighting on/off switch and the engine kill switch, with another loom clamp
To get to the lighting control, I removed the clamp and lever to reveal the switch itself. It consists of five components: the switch block, contact board, sliding contact, detent spring and ball (more on these later). All of this just pulls out of the housing, where it's held in place by grooves molded into the shell itself; but be careful. The detent ball and spring (inset), just visible at the top of the block in this shot, are under compression and will want to fly as you pull the switch out. I just kept a finger over it and had no trouble retaining the ball and spring
Removing the lighting switch reveals the e-clip for the kill switch knob. Pull this off, and the knob is free to remove; but, once again, be aware of components under compression. The knob contains yet another detent ball and spring, along with a brass contact and its spring (inset). All of these tiny parts are just straining to be free; so I kept pressure on the knob as I removed the e-clip, then carefully lowered the knob away from the housing over a sheet of white paper (all the while humming "Born Free" to myself). The detent ball fell out, but was caught by the paper, so no hassles here
After the knob is removed, the kill switch board just pushes up out of the housing, where it can be detached from the harness with a soldering iron
On the starter button side, removing the loom clamp allows access to the starter switch components; four in all. They are the starter button/contact stud, button spring, and the G/R (clutch) and Y/R (SSU) switch leads and contacts
With the G/R lead removed, the Y/R contact board slides out of a slot molded into the body of the switch housing, and the button and copper spring can be removed. The spring is under no great tension; I held it back with a pair of tweezers when removing the G/R lead, as the spring seats against it
So here we have it. A godawful pile of tiny little pieces just waiting to be lost, mixed up or in general mutilated beyond description. It's a good idea to keep everything in its own little grouping, so I just tossed things in plastic baggies as I completed each step
Cleaning and Inspection
Now that everything is apart, it's the time for cleaning and inspection. I think the biggest reason these old switches fail is because of the thirty-to-forty year old grease that they're all packed with. By now, it's mostly evaporated and turned rock hard. Spray everything off with contact cleaner to get rid of most of the old grease, then take emery paper or 0 or 00 steel wool and make sure everything made of metal gleams. All of the contacts need to be clean and grease free. Special attention should be placed on the "teeth" on the inside of the sliding contact as that is what makes connection with the spade contacts. Everything needs to shine like it was brand new. Spray out the spring seats in the kill switch knob and the sliding block to get rid of all of the old, nasty dried-up grease. Soak the springs in alcohol or what-have-you so they're sparkly clean as well. Once everything is shiny, spray it all out well again with contact cleaner. Again, the emphasis is to make everything inside the switch look as close to new as is possible. I've taken a few old veterans apart now and, aside from the ubiquitous spider nests, most have been pretty clean inside... at the very least they all were in decent, usable shape after a good cleaning.
Check the contacts for serious wear and tear. Shallow grooves are okay, but trenches went out with WW1. The lever stud at the top of the sliding block should stand tall and proud; if it is too badly distorted, cut it off and substitute a small machine screw with washers added to match the original configuration. I've done it (long ago - don't have pics) and it works just fine. Be creative. Also, check the fit of the sliding contact in the block; make sure the block grips the contact and doesn't allow lateral movement of the contact within the block.
Check the G/R (primary) lead to see if the nylon extrusion it's embedded in is cracked. If it is, it can be repaired by adding plastic shims as described below.
Once again, everything should be so darn clean prior to re-assembly that
your mother could eat off of it...
Reassembly and Testing
There are some tricky areas to consider when putting these things back together; mainly because they have lots of small springs and other things to fool with that require the use of at least three hands and a 5X eyeball for proper installation. Have no fear; it's not as hopeless as it initially appears. I started with the kill switch and soldered the black & black/white switch harness wires to the contacts (it doesn't matter which wire goes to which contact) on the little phenolic board
The kill switch knob itself contains these two little springs, a steel detent ball, and a brass or copper contact. Note the difference in the springs. The larger diameter spring goes with the detent ball, while the skinnier spring is used with the brass contact. In this pic, the contact spring is the shorter of the two; in other (stock) switches I've looked at, this spring is the longer spring. This is the only difference I've found between this aftermarket switch and the stock switch, and it has to do with the contacts being thicker on the aftermarket board. Whatever; the contact spring is always the skinnier of the two
Following Honda's lead, I used a little light grease (brake pad anti-squeal grease from the local auto parts store is perfect for this stuff) down in the slots on the contact side (keep the contact clean) and down the bore on the detent ball side to help hold these parts in position...
...then added a dab to the detent slots in the housing
After flipping the housing over, I moved the work over a large sheet of white paper (in case of falling parts) and carefully inserted the knob from underneath, making sure it was oriented correctly with the detent slots (ball side) and contact board (contact side). It was simple and easy to do, and adding the e-clip finished the assembly
I tested the movement of the knob by turning it from stop to stop, and was rewarded with a friendly "click, click" from the detent ball as I did so. The knob turned smoothly, with positive stops in each position.
This is a pretty important little switch, and the only one that remained unchanged between the different models. If necessary, it will shut down the engine like right now. Perusing the wiring schematic indicates that power from the voltage regulator feeds through here to the coils, thence to the spark plugs. Switching to the "OFF" position breaks this circuit and cuts power to the coils, but doesn't affect the rest of the electrical system. I've seen lots of people shut down their engines to park using this switch. I don't know if this is a good or bad practice; all I can say is don't forget to shut off the ignition switch, too, as these things don't run with a dead battery...
With all of the above in mind, I ran a continuity check just to make sure everything was copacetic
On to the next component, the lighting switch. It consists of a lever (not shown here), a plastic block with its accouterments of detent spring/ball and sliding contact, and a phenolic board stuffed with a series of spade contacts. This is a very simple switch, and I thought I'd take a closer look
The sliding contact fits into a slot in the block, which then sits down over the spade contacts. The block grips the sliding contact and, through manipulation via the lever, moves it between (in this application) two states: off and on, or an open or closed circuit
Travel is limited by the spare spade contacts (top row in above pic) interacting with the block, and the detent ball and spring, which moves between slots cast into the switch housing. As noted before, this shell is used for other applications that call for a three-position (OFF/LO/HI) switch, hence the three detent slots...
Assembly of this switch is a little delicate; it's one of the places where three hands would be useful. I used some emery paper on the spade contacts and sliding contact to get them sparkly clean, then sprayed everything out with contact cleaner. I inserted the sliding contact into the block (top slot next to the lever button - see the inset a couple of pics above), then fitted it down over the spade contacts in the center (off) position. I then inserted the detent spring into the bore and added a dab of grease to help hold the ball in place during assembly
Now, I think this next procedure is the one where everyone takes one look and says "No way!" Don't let the little ball and spring defeat you before you begin! It's really quite simple once you learn the trick to it, and afterwards you'll kick yourself for being so squeamish. Here's the tip: the phenolic board fits down into two slots cast into the body of the shell. Holding the block in place, insert the board/block combo about half way into the slot, then add the ball, embedding it in the assembly grease and centering it over both the block bore and detent slot in the shell. Using a knife tip...
...press the ball down into the bore while sliding the block/board combo down into position. Believe me, it's a lot more difficult to describe than it is to do...
...and there it is... a lighting switch! With everything in place...
...adding the harness clamp and switch lever completed the sub-assembly (note that the wiring clamp serves three purposes here: first of all to keep all the wiring together; secondly to hold our switch assembly in place [the vertical oblong feature in the center of the photo is a depression that bears against the phenolic board and keeps everything solid] and. thirdly, the long finger stretching out to the right acts as a stop for the lever)
With everything in place and moving cooperatively between detent stops, I tested the switch with the VOM
With the top half of the switch completed, I turned my attention to the bottom half: the starter switch.
Now, when I was a mere child busily burning up the streets of Boulder, Colorado, I had occasion to remove the right hand switch/throttle housing a couple of times (this was on a '69 CL350, but I believe most of the Hondas out in the early days shared the same right switch), and in those days it was the three-position lighting switch and a simple one wire/one contact starter switch. Pressing the button simply grounded the starter circuit against the switch body, and kicked on the solenoid (AKA the Starter Magnetic Switch, or "SMS"). In fact, the horn button on the left hand control continued to use the same set-up, with a single metal tab and contact disc.
The Starter Motor Safety Unit (SSU) changed all of that. While the button still completes the starting circuit, things have become a bit more complicated. This is what I can gather from perusing the wiring schematic (and this is my own interpretation and may well be a total crock). When the ignition switch is turned on, the SSU is powered up and ready to trigger the solenoid (SMS); but first certain conditions must be met. In a way it acts kind of like a judge at a track meet, waiting until all of the runners are properly lined up and ready to go before signaling to the guy with the starter pistol. In the case of the SSU, it wants to power up the SMS; and it's sending out signals to the starter switch in a big loop that includes the neutral switch, the clutch switch and the starter button, asking, "Are we ready yet?". If all conditions are correct, that is, if the neutral switch is in the "ON" position and/or the clutch lever is pulled (activating the clutch switch), then pressing the starter button completes the loop and signals the SSU to provide power for the SMS, which (hopefully) eagerly complies by jumping to it like the good little trooper it is.
The next generation of starter switch progressed even farther to include aspects of the lighting system. It was introduced in 1975 (in the US) on the "F" models, and the "K" bikes followed suit in 1976. This switch "hard-wired" the headlight "ON" when the ignition was switched on: essentially it is a SPDT (Single Pole/Dual Throw) switch that diverts power to the starting system (depressed) or to the headlight (released). This is necessary because the headlight draws so much power that if it were to remain "ON" during start-up it would starve the coils and play havoc with the starting sequence, among other things...
The infamous "Hard-Wired" switch
The reason for this change is an interesting story in itself. Inquiries starting in the mid '60s indicated that fatalities from motorcycle accidents were beginning to increase (not surprising considering the new Hondas and other small, sporty bikes that were suddenly appearing on the market. Before that, you either rode a scooter [NOT A MOTORCYCLE], or you were consigned to the "Big 'Ol Ratty Monster Killer Hog" crowd and had to consort with folks named "Cryptkeeper" and "Switchblade" who had bits of railroad spikes stuck between their teeth). In fact, a conclusive 1978 report disclosed that the number of motorcycle fatalities in the US rose from 675 a year in 1963 to 3300 a year in 1976.
Between 1967 and 1973, due to early results gained from these inquiries, 14 states began requiring daytime headlight use on motorcycles, and in 1972 California enacted a law mandating all new bikes sold in the state be "hard wired" with the headlight permanently on - although they didn't actually implement it until 1978. The motorcycle manufacturers went into a panic over this, as California represents a huge segment of the US motorcycling public, and immediately began making plans to hard-wire
all of their bikes headed for the US and Canadian markets, essentially extending application of the California law to the whole of North America.
While most states require daytime headlight operation, not all do and, in fact, there is some controversy over some of the conclusions contained in the earlier studies. Inconsistencies of methodology have been uncovered; things like changes in accident reporting by the police over the years and other variable factors tended to skew the data; and some states reported that there was no change in accidents at all - while in Montana motorcycle fatalities actually went up - after they started requiring daytime headlight use. Current inquiries have focused more on the motorist's perception of an oncoming motorcycle, lights or no, and of the actual characteristics of human vision itself; but if you want an honest and straightforward conclusion as to whether daylight headlight usage actually does help cut down on fatalities, the jury is still out after 43 years of research.
Me, I believe in daytime headlights for motorcycles because I figure every tiny thing I can do to try to increase my visibility is just one more factor in my favor. Even though the data may not completely back that up, it still gives me a comfortable feeling to have that light on. And, anyway, it's the Law in Colorado. The main thing I don't like about these "hard-wired" switches is that they take away your freedom of choice; just another instance of "The Man" laying down "The Law" and telling us what to do whether we like it or not, as far as I'm concerned...
But, I digress.
The other thing I like to rant about with these switches is that they're just cheaply made of thin plastic (or nylon), then stuffed into a hollow metal ball that is anodized black and is subjected to strong sunlight. Temperatures inside one of these switch housings must reach 130 degrees or more in the summer, and that nylon bakes away in there year after year until it's fried to a crisp. It can result in catastrophic failure of the switch. Just ask me. I know.
Brighter minds than mine on this forum have suggested (and I agree) that, if your '76 and later kill switch is working and the starter switch is doing its thing, you'd be best off not to mess with taking the right switch apart because the switch housing may be the only thing holding that starter button assembly together
When it fails (note I did not say "if") you'll know it; the starter button simply sinks away into the switch housing and disappears. Unfortunately, there isn't any way to repair one of these when it self-destructs, at least as far as I know. There are some very helpful posts on this site that cover replacing this starter switch with other types of SPDT switches (do a search), and there are aftermarket versions of the entire right-hand switch (running @ $110 each) available on ebay or through Yamiya or David Silver Spares, to name just a couple of sources.
Here are some ways to get around this problem proferred by two of the forum's heftiest authorities. When you find your switch is no longer functioning, Hondaman suggests the folowing:
"There are 2 easy solutions:
1. Inside the headlight, find the wire that feeds the middle fuse of the fuseblock. This circuit usually has a Blk/Red or Blk/Brn wire coming from that Start button, and it may even change color to become Blk/Brn enroute to the fuse, right there in the headlight. For example, the wire from the switch might be Blk/Red, but is plugged into a Blk/Brn to go to the fuse. Honda had some of these foibles in the 750"F" bikes...at any rate, you can unplug the feed wire to the fuse from teh pushbutton, then plug it into an available Black circuit in the headlight. This will leave the headlight always ON when the bike is ON, but it works.
2. If you want to still keep the "off when starting" function, you can install (or buy one of my kits for a prebuilt version) a relay that follows the Start button and disconnects the headlight from this same Black wire circuit. It's simple to do: just feed the relay's COMMON terminal from the Black circuit and connect the middle fuse's wire (usually Blk/Brn on 750 after 1974) to the NC contact on the relay. Then ground one side of the relay coil to a Green wire and connect the coil's (+) contact to the Start solenoid circuit (usually Yel/Red in the 750). Then this relay engages when the Starter does, opening the power to the fuse for the headlight.
The keyswitch on these bikes controls the taillight circuit, not the headlight circuit."And Two Tired adds:
"There are a few alternatives for repair.
1 - replace the entire control group. It seems the newer replacements use a different plastic material than earlier ones, which seem to be more robust.
2a - Replace the switch with a single pole button for the starter.
2b - Then hard wire the head light on with Key switch control. (This lowers voltage for coils during electric start.)
3- same as 2a but add a switch elsewhere to control the headlight power.
4 - same as 2a except add a relay for the headlight that disables the headlight when the starter solenoid is energized."Good Luck!
Our starter switch consists of a hollow plastic button, a small brass cup with a brass contact stud protruding from it that fits into the bore of the button, a copper spring, and two wiring leads: one I call secondary (yellow/red) in the SSU/SMS circuit and the other (green/red) in the SSU/clutch switch circuit (primary).
To begin assembly, I inserted the copper spring down over the brass contact stud and seated it in the cup, then slid the starter button through its hole in the housing. The "channel" that the button slides into is rounded on the bottom (like a glacial valley), so it's easy to get the button in right. After this comes the secondary lead (Y/R) which ends in a shield-shaped phenolic contact board. The board inserts into a slot formed into the body of the switch housing, much like the board on the lighting switch did, with the rounded side down and the contact side facing the starter button assembly
Holding the board in place with a thumb, I fitted the primary lead from the clutch switch (G/R) down between the button and secondary (Y/R) contact board. The clutch lead ends in a brass tab with a hole on the long end and it, too, is rounded to fit the switch slot. The tab is insulated from ground via a nylon extrusion into which it is embedded, and which contains a beveled mounting hole. An oval-head machine screw locks this contact in place against the switch body
In operation, the spring acts in two ways: it provides the tension necessary to keep the circuit open and the starter button from flopping around, and it acts as an electrical conduit between the primary (G/R) lead and the contact stud embedded in the button. When the button is pushed there'll be no running away... Umm... sorry - flashback... Um, when the button is pushed, the spring-energized stud is propelled through the hole in the primary tab to impale the secondary contact and literally close the circuit, thus initiating the SSU in its starting sequence.
Now, on the older switches we discussed with the "OFF/LO/HI" lighting control, the setup for the start switch button is very similar to this, the difference being that the G/R lead does not exist and the primary contact is made completely of metal without the nylon extrusion
It still features a tab with a hole in it as described above, and the button and spring, but in operation the primary tab is screwed into the body of the switch, and when the button stud contacts the secondary (Y/R) contact it grounds the starting circuit, activating the SMS.
Here's a close-up shot of everything put together. One thing about this particular switch is that, once I had it all assembled and was testing it, I noticed that as I pushed the button the primary contact wanted to move, even with the screw dangerously tight. I reckon it doesn't take much to split the nylon mount at the screw, especially since I've seen it that way in original switches, so moosing down on the screw was not an option. I got one of those plastic bread tie clips, cut it in two, and superglued the pieces in beside the contact, as you can see here. Now it doesn't move and the button is firm and stable (Original switches I've examined are a little tighter here, so they may not need this; but if your nylon mount is split, it works well as a repair).
And, finally, adding the loom clamp finishes off the sub-assembly. I was aware while assembling this that I needed to be careful of the wiring harness, making sure it was clamped in the right position. Too much slack and you won't be able to close the switch housing around the handlebar. Not enough and you get the same results. Like the little blonde chick said, "It's gotta be just right". Fortunately, marks in the harness itself told me where to plant the clamp, so it was easy
One more sub-assembly to consider is this little collection of parts. Known as a "Throttle Adjuster Screw", it resides in the throttle section of the switch housing. Honda seems to have used these on a number of bikes; the '74 model was the only 550 to implement it. The moon-shaped flat spring fits down into a recess in the throttle body with the curve towards the throttle pipe, and the screw and coil spring screw in from underneath, thereby making adjustment of the flat spring possible. I guess this was supposed to keep the throttle grip stable... to be honest, I'm not really sure what the real purpose of this thing is, and evidently Honda wasn't either as they were discontinued on all subsequent models. I reckon adding it, deleting it, or adding it and making it non-functional is your call (EDIT: I have found, since this was originally posted, that this is used mainly as a device for maintaining the throttle at specific RPMs during engine tuning. Here's a quote from Goofaroo that is an excellent description of its use:
"I've had a few BMWs and they've all had one of the "throttle adjuster screws". I was pleasantly surprised recently when I took the bars and controls off of my 1971 CB500 project and discovered that it had one of these. BMW riders including myself have always used them as a cruise control. By design they can be adjusted to hold the throttle steady but overridden as needed. I'll usually tighten it up a bit for the long boring straight line highway runs and then back it off when I get to town or some twisties.
That being said- the actual reason for it is for tuning purposes and to be able to hold the throttle at a desired RPM setting. My boxer has always run best if I syncronize the carbs at 3000 RPM instead of at idle.").
Thanks again, GFR!
Of course, we now perform the obligatory continuity test on the starter button
And there we have it: the right-hand switch from start to finish. It didn't turn out to be as hair-raising as I feared it would be, and was actually quite simple. All it required was a little attention to detail. With new ones running over a hundred dollars each (if you can find one of this type, that is), it's worth it to spend 20-30 bucks at a salvage yard to pick up a decent switch and refurb it. Give it a try!
'til next time!
