This is NOT Rocket Science! With old bikes it’s a mistake to fix things only when they break. To achieve reliability, perform a methodical revision of all basic systems and then continue with regular preventive maintenance. For all my bikes, I methodically clean, repair and protect as much as I can. I want to know, not guess, my wiring is good.
Here’s what you need:
- Q Tips
- Electrical contact cleaner (Radio Shack or other)
- Small wire brushes & a few scraps of fine sandpaper
- Di-electric grease
- Color copy of the wiring diagram.
Go through the entire bike, following the color-coded wiring diagram, disconnecting and cleaning every connection, just a thin smear of dielectric grease and be real sure that the connectors re-connect properly. Only do a few connections at a time so you don’t create grief.
Pay special attention to the plastic plugs behind the left side cover. The most important and vulnerable plug of all is on the wiring from the stator. It gets pretty warm and tends to deteriorate and fry. See below for replacement connectors. Some people just eliminate the connector and solder the leads. If you do this, use appropriate shrink tube or tape the connections well. Make sure you clean all the battery lead connections at the frame for the ground, the solenoid connections and power to the starter. Don’t just do the easy ones!
Check all the wiring for signs of chafing, especially in hidden places where you’d never look normally, under the tank, by the steering head. Look also for signs of wiring being pulled tight. With the tank and seat removed, turn the handlebars from full lock one side to the other and see if anything is being stretched or chafed against the frame.
Be thorough. Do the the connections inside the headlight. I start this area by taking a digital photo of the morass of connections so I know how it all goes back together. I do likewise whenever I take something apart unless I’m really sure I can put it together without a problem.
Open up the handlebar switch halves. Clear out any debris you can then spray them out with contact cleaner. Either blow them out with compressed air or air them out long enough to be sure the cleaner
has evaporated. Go easy with compressed air in switch areas. You want to dry them out, not damage anything. Wherever possible, use Q Tips and/or small wire brushes to clean contacts. Be very careful
that none of the fuzzy cotton tips of the Q Tips is left on the item being cleaned. Follow along on the wiring diagram as you work and you’ll learn your wiring. Never do a whole load of connections at once or you may end up cross connecting something.
While you are at it, change any old glass fuses. Glass fuses can look good and still malfunction (I lost a few hours on that last year on one of my 550s). Don’t forget to brighten the metal holders for the fuses with a small wire brush or a bit of emery cloth. Clean all light bulb fixtures, making sure the metal socket tube is polished up inside and the spring loaded center is clean and moving freely.
For Hondas with the old blade style main fuse, for about 15 bucks you can simply replace it with a modern weatherproof unit. Just put ring ends on each lead, then connect on lead to one of the blade fuse screws and the other lead on the other screw. On CB900C/1000C, consider doing the well documented coil bypass wiring to improve power to your coils.
For all Hondas using HTI (Honda Transistorized Ignition) 1979/80 depending on model, thru at least 1983 which is sometimes (especially in Clymer manuals) referred to as CDI (Capacitor Discharge Ignition), there are some small units called “spark units” or “igniters”. These have a black epoxy-like material inside an aluminum heat sink. They are interchangeable across all models so scrounge spares when you can. New, they’re about $175 US each.
Inspect your igniters. If the black stuff is sticky, it’s starting to fail. If it’s started to drip, it’s dangerously close to failure. Your Regulator/Rectifier is of similar construction. Again, look at that black stuff to get an idea of what’s what. Make sure igniters and R/Rs are well fastened to a grounded location. Always have the Run/Stop set to Stop unless you’re running the bike. Never crank the bike for something like a compression test with that switch set to Run. Ignoring the fire hazard you might
create, no electronic ignition deals with this sort of situation well.
Bad Batteries are Bad News
Another thing that causes extreme stress on charging systems is a weak battery. Bad batteries are one of the primary reasons for Regulator/Rectifier failure. Don’t try to fudge it and make do. If you’re
holding out for a maintenance free Yuasa, yeah they’re great but go get a cheapo Walmart thing in the meantime. It’ll last a couple of seasons with reasonable care. Otherwise you maybe replacing much more expensive components soon.
Trouble shooting on ‘common ground’ systems
When trouble shooting 12 volt electrical on vehicles, one of the most common problems is poor grounding. Vehicles use a mix of ‘common ground’ where a metal chassis is used as a ground instead of running ground wires off every fixture back to the battery.
If you have problems:
- check the fuses with meter
- check the battery’s grounding to the chassis
- check each fixture’s grounding to the chassis.
For that last item, good trouble shooting technique is to attach a piece of 14 gauge or heavier wire to the battery’s negative and use it to ground an offending fixture. If it suddenly starts working with this lead attached, then you know the normal means by which it grounds is not working. You don’t have to rewire anything, just clean up the grounding whether it’s a wire or grounding by bolting to the frame.
What NOT to do
Resist the temptation to just do a shotgun approach to a problem. Work it through, either from the fixture to the battery or vice versa. If you just ‘try this’ and then ‘try that’, you may waste a ton of time. Also, if you clean up your electrical before problems arise, there’s far less chance of random issues popping up in numerous places.
The worst thing in mobile electrical comes when someone doesn’t understand a problem, so they attempt to “rewire” an existing circuit. Often they leave old hot wires dangling and create new circuits that aren’t properly fused. The goal should be to simply re-establish the original pathways.
Original Connectors are Available!
All vintage Japanese bikes used the same connectors made by Hitachi and until recently all manufacturers offered kits including service tools and individual parts (sold to dealers in boxes of 5).
But dealers generally didn’t stock the parts so if you wanted “one of these” the cost, if they were willing to order it for you, was ridiculous. So people wrongly assume you can’t get originals.
Check these supplier sites:
www.easternbeaver.com
www.vintageconnections.com
www.crc2onlinecatalog.com
www.oregonmotorcycleparts.com
www.qualitycycleparts.com
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