Topic: Electrical issue where to starr debugging?

[amitr0]

New to all this, looking for suggestions:

Symptoms:
I test battery voltage before starting, it is reading somewhere in the 12-13v range. The battery is new lead acid.

I start my bike, no problems. Open the throttle while holding a multimeter to the battery, the viktage shows above 13.5, basically indicating that it charges.

I take the bike for a spin, drive around for 20 mins, stop at a coffee ahop, when i come out, bike wont start with starter motor. The battery has gone below 12v. Luckily kick start works, and i drive away.

This is a regular pattern. Battery does hold charge over night, or over a few days if i dont start.

Where do i start looking?

It is a 76 cb550k, in case that matters.

[Alan F.]

Likey there is not one cause but many dirty connections throughout your electrical system. These connections need to be disconnected or disassembled one at a time, cleaned and coated with dielectric grease, then reconnected or reassembled. This includes all lightbulb sockets and frame grounding points.

Once this is done, give it a try. If the problem remains then troubleshooting can begin.

Search YouTube for cleaning motorcycle electrical connectors and watch a few videos.

Don't think too deeply on it, when a flashlight blinks out the first thing you'd do is rattle it and knock it with your hand to jostle the connection at the batteries or bulb, it could be just that simple on your bike. A clean electrical system will make any bike more reliable.

[amitr0]

Likey there is not one cause but many dirty connections throughout your electrical system. These connections need to be disconnected or disassembled one at a time, cleaned and coated with dielectric grease, then reconnected or reassembled. This includes all lightbulb sockets and frame grounding points.

Once this is done, give it a try. If the problem remains then troubleshooting can begin.

Search YouTube for cleaning motorcycle electrical connectors and watch a few videos.

Don't think too deeply on it, when a flashlight blinks out the first thing you'd do is rattle it and knock it with your hand to jostle the connection at the batteries or bulb, it could be just that simple on your bike. A clean electrical system will make any bike more reliable.

Some of these points are crunchy, might break, the wires are also stiff and the insulators crisp, one of my fears it it might end up having to buy a new harness. My bike is a 76 550k, harnesses are not available for it anywhere(new ones).

[Alan F.]

Connectors can likely be replaced, there are little tabs on each individual wire connector in those block connectors, each wire can be extracted from the old brittle connector, cleaned & greased (and it's little lock tab bent out again) and inserted into its proper place in a new connector of the same type.

Brittle wires may simply need to be replaced. The wire harness can be removed from the bike and carefully unwrapped to enable you to better determine and replace what needs it. This all sounds complicated but it's not.

[amitr0]

Connectors can likely be replaced, there are little tabs on each individual wire connector in those block connectors, each wire can be extracted from the old brittle connector, cleaned & greased (and it's little lock tab bent out again) and inserted into its proper place in a new connector of the same type.

Brittle wires may simply need to be replaced. The wire harness can be removed from the bike and carefully unwrapped to enable you to better determine and replace what needs it. This all sounds complicated but it's not.

Thanks. If it comes to getting the tape wrapping off the loom and swapping wires out with new ones, perhaps it is better to get a new aftermarket loom?

[Alan F.]

Right. These bikes love to rev high, can't ride them the way you'd drive a car.

Have your battery "load tested" at an auto parts store. New batteries do fail.

[amitr0]

Battery voltage “somewhere between 12v and 13v” is not an indication of a fully charged battery. 12.8-13.2v is fully charged.

These bikes (500, 550) do not produce excess voltage beyond the demand of the lights, coils, and ignition unless the motor is being operated above 2,500 RPMs for extended periods. So if you are nursing the motor along in city/suburban traffic, YOU are the cause, not necessarily the electrical system.

Sure, thorough maintenance should be conducted, but first amend your rising habits. Also, far too many people assume new batteries are “good” and therefore the problem lies elsewhere. With electrical, accurate, diligent diagnosis is required. Otherwise you’re tossing money at parts without assurance of solving the problem.

I see. What is the idle RPM? My tach is currently broken, ao I do not know.

When i said I rode it, it wasnt just city traffic where we stop and go on aignals. This was a trip for 20 mins on a road where riding at 55mph was done.

What are 'rising' and 'nursing' habits? I am not familiar with these terms.

[bryanj]

Idle is about 1200, maybe a bit lower. 55 in to is probably 4000 ish so with lights on not charging a lot

[Alan F.]

Simply put, treat your 500/550 as if it were a modern 600cc sportbike where the peak power starts to come in 1/2-2/3 through the rev band, that's where these bikes charge best. Ride in the higher RPMs like those guys do and you'll be fine. Just check your oil regularly.

[MauiK3]

I have had otherwise good batteries just fail quickly, they often are defective.

[amitr0]

“Nursing” is being afraid to wind the motor up because you fear it is a small, fragile, old beast. You should be in the habit of riding well above 4,000 RPMs in second through fifth gear to optimize the motor’s potential.

“Rising” is a typo, “riding” was my intention.

I see thanks. First order of business is to fix the broken tach then.

[madmtnmotors]

Takes me about two weeks working nights and weekends to rehab the entire harness on a CB750:

http://forums.sohc4.net/index.php/topic,137351.msg1549191.html#msg1549191

For those connectors that need replaced you can usually cut the old connector off right at the crimp which will only sacrifice about 1/8" of wire. Electrical troubleshooting is kind of a Zen thing and often requires figuring out what it's NOT...

EZPZ 

[Alan F.]

Thanks Madmtnmotors I'd never seen that thread.

[RAFster122s]

The revs might sound high to your ear but you are likely to estimate high. The 550 starts coming alive at 5500-6000 rpm and its power band is fun to ride that way, especially in twisty roads.
It isn't a Harley so don't try to make it sound like one. Lugging the engine at low rpm in higher gears is not healthy for the motor.

Charge your battery and try riding it at higher rpms and see if your battery doesn't respond well. Clean and bit of dielectric grease on the contacts...couple hours every evening and you might be done before Christmas.
Identify areas that need new connectors and put order in at Vintage Connections for replacement bullet and barrel (female side) connectors and get their crimping tool.

[Deltarider]

So far I never had to take any connector apart for cleaning, let alone to apply whatever 'nursing' grease on my 45 year old CB500. The only electric part that went bad, was the IGN key switch.
Realise that Americans tend to ride their bikes at a too low rpm, used as they are to the oversized engines in their cars which were designed to produce a much wanted gurgle-gurgle sound, rather than being economical means of transportation. Cheap gas has made this possible.
Check your battery is still good. A couple of hours after charging, voltage over the terminals should be 12,6V or higher (IGN off).
In all my documents on CB500/550s in particular, including riders reports composed by owners that at the time had used their bikes for a total distance of 40 times around the globe, the charging system has never ever been criticized. It's merely an American complaint. To be honest, that silly 'headlamp-always-on-arrangement' (forced upon customers in the US only) is also to blame and the added nonsensical gadget running lights in the blinkers that waste an extra 16 Watts. No other markets had these wiring arrangements and there is a reason for it. So this often discussed and socalled 'charging deficiency' is easily adressed by returning your bike to how Honda it originally had designed.

[RAFster122s]

Delta, blah blah blah
Go away, your bike is perfect, everyone knows it, your maintenance procedures are perfect, your bike never being neglected never had to come back some into a normal state of repair like his needs to...
 just go away as you are not helpful

[pjlogue]

Some of these points are crunchy, might break, the wires are also stiff and the insulators crisp, one of my fears it it might end up having to buy a new harness. My bike is a 76 550k, harnesses are not available for it anywhere(new ones).

The crunchy/stiff wires would indicate overheating which is caused by dirty connectors.  If the connectors get hot they loose their temper and become soft thus worsening the bad connection.  If you replace the connectors make sure you cut the wire back enough to get to real clean wire.  Oxidation on the wire end prior to crimping will just perpetuate the problem.  You may want to asses the wire harness and think if you would be better off springing for a new harness.  If just a few connections are bad then repair would be the better option but if a lot of the connections are bad I would say a new harness would be a better way to go given that replacing the connectors is quite time consuming.

-P.

[Alan F.]

I took a look too and didn't see any aftermarket harnesses for 76 550K, what other harness is appropriate? Earlier, Later or 550F?

I've got some crunchy wires in my 750K8 harness, I'll probably just replace those runs completely with new correct color code wire and crimp new terminals on. All of my block connectors are trash. The aftermarket harnesses that are available aren't perfect matches to stock by the way. Hondaman has a thread somewhere about making additions/corrections to those to make them much better.

I'll continue to keep an eye out for a nicer used K8 harness.

[1080]

Did you check for Battery drain? Connect and ammeter to the battery and see if there is current flowing without the key in the ignition.

[amitr0]

The revs might sound high to your ear but you are likely to estimate high. The 550 starts coming alive at 5500-6000 rpm and its power band is fun to ride that way, especially in twisty roads.
It isn't a Harley so don't try to make it sound like one. Lugging the engine at low rpm in higher gears is not healthy for the motor.

Charge your battery and try riding it at higher rpms and see if your battery doesn't respond well. Clean and bit of dielectric grease on the contacts...couple hours every evening and you might be done before Christmas.
Identify areas that need new connectors and put order in at Vintage Connections for replacement bullet and barrel (female side) connectors and get their crimping tool.

Alas, @calj737 might be right, i am a docile rider, enjoy engine braking and using the clutch to reduce speed temporarily instead of brakes kinda guy

[amitr0]

So far I never had to take any connector apart for cleaning, let alone to apply whatever 'nursing' grease on my 45 year old CB500. The only electric part that went bad, was the IGN key switch.
Realise that Americans tend to ride their bikes at a too low rpm, used as they are to the oversized engines in their cars which were designed to produce a much wanted gurgle-gurgle sound, rather than being economical means of transportation. Cheap gas has made this possible.
Check your battery is still good. A couple of hours after charging, voltage over the terminals should be 12,6V or higher (IGN off).
In all my documents on CB500/550s in particular, including riders reports composed by owners that at the time had used their bikes for a total distance of 40 times around the globe, the charging system has never ever been criticized. It's merely an American complaint. To be honest, that silly 'headlamp-always-on-arrangement' (forced upon customers in the US only) is also to blame and the added nonsensical gadget running lights in the blinkers that waste an extra 16 Watts. No other markets had these wiring arrangements and there is a reason for it. So this often discussed and socalled 'charging deficiency' is easily adressed by returning your bike to how Honda it originally had designed.

I am in america, the bike is american version, but i learnt riding in a third world country where getting to 3rd gear is a luxury.

I am sure i jave carried that habit here, i tend to rely more on engine braking and wngage the full clutch to resuce speed temporarily if needed.

[amitr0]

Some of these points are crunchy, might break, the wires are also stiff and the insulators crisp, one of my fears it it might end up having to buy a new harness. My bike is a 76 550k, harnesses are not available for it anywhere(new ones).

The crunchy/stiff wires would indicate overheating which is caused by dirty connectors.  If the connectors get hot they loose their temper and become soft thus worsening the bad connection.  If you replace the connectors make sure you cut the wire back enough to get to real clean wire.  Oxidation on the wire end prior to crimping will just perpetuate the problem.  You may want to asses the wire harness and think if you would be better off springing for a new harness.  If just a few connections are bad then repair would be the better option but if a lot of the connections are bad I would say a new harness would be a better way to go given that replacing the connectors is quite time consuming.

-P.

I see, that definitely zones into my area of primary investigation

[amitr0]

I took a look too and didn't see any aftermarket harnesses for 76 550K, what other harness is appropriate? Earlier, Later or 550F?

I've got some crunchy wires in my 750K8 harness, I'll probably just replace those runs completely with new correct color code wire and crimp new terminals on. All of my block connectors are trash. The aftermarket harnesses that are available aren't perfect matches to stock by the way. Hondaman has a thread somewhere about making additions/corrections to those to make them much better.

I'll continue to keep an eye out for a nicer used K8 harness.

That is correct, even i couldn't find any. There is a thread here somewhere regarding that as well.

This is also another reason for me not to mess with it much.

The 76 seems to be a rare one year bike.

I am told the 75 k model might match, nut i am yet to properly diff the two to be able to confidently buy one.

[amitr0]

Did you check for Battery drain? Connect and ammeter to the battery and see if there is current flowing without the key in the ignition.

Yes, this was suggested elsewhere, i will do it soon

[TwoTired]

Are you aware that the key switch has three positions?
Off - On - and park. The later will stop the engine and allow key removal but leaves the tail light on to drain the battery, which I have experienced a few times.

Cheers,