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From: rugger81 on 9 Aug 2006 16:28
I just bought an old cb750 recently and now I'm having some electrical
problems. I was riding down the rode when all of a sudden the bike
stalled out. I pulled over to the side of the road and I noticed all
the electrical was out. I tried kick starting it and push starting it
and I even got someone to try and jump start the bike but all I got was
the power to flicker a couple of times. The battery is brand new so
that shouldn't be the problem. I don't have the money to go take it to
a shop and get reamed so I want to try and fix it myself. I think
maybe the power is shorting into the frame somewhere, but I don't know.
Anyone have any advice for me? thanks in advance.

-Joe

From: monk on 9 Aug 2006 17:15
rugger81 wrote:
> I just bought an old cb750 recently and now I'm having some electrical
> problems. I was riding down the rode when all of a sudden the bike
> stalled out. I pulled over to the side of the road and I noticed all
> the electrical was out. I tried kick starting it and push starting it
> and I even got someone to try and jump start the bike but all I got was
> the power to flicker a couple of times. The battery is brand new so
> that shouldn't be the problem. I don't have the money to go take it to
> a shop and get reamed so I want to try and fix it myself. I think
> maybe the power is shorting into the frame somewhere, but I don't know.
> Anyone have any advice for me? thanks in advance.
>
> -Joe
>


Try following through this fault finding chart. It helped me get through
the electrical issues with both the bikes I'm working on. (74 RD350 and
81 KE125)

cheers
From: monk on 9 Aug 2006 17:15
rugger81 wrote:

> I just bought an old cb750 recently and now I'm having some electrical
> problems. I was riding down the rode when all of a sudden the bike
> stalled out. I pulled over to the side of the road and I noticed all
> the electrical was out. I tried kick starting it and push starting it
> and I even got someone to try and jump start the bike but all I got was
> the power to flicker a couple of times. The battery is brand new so
> that shouldn't be the problem. I don't have the money to go take it to
> a shop and get reamed so I want to try and fix it myself. I think
> maybe the power is shorting into the frame somewhere, but I don't know.
> Anyone have any advice for me? thanks in advance.
>
> -Joe
>


sorry, this is the link to the chart.

http://www.electrosport.com/Images/fault_finding.pdf
From: 'Lefty' on 10 Aug 2006 01:05

"rugger81" <jgilchrist(a)ots.net> wrote in message
news:1155155299.751089.62800(a)i3g2000cwc.googlegroups.com...
>I just bought an old cb750 recently and now I'm having some electrical
> problems. I was riding down the rode when all of a sudden the bike
> stalled out. I pulled over to the side of the road and I noticed all
> the electrical was out. I tried kick starting it and push starting it
> and I even got someone to try and jump start the bike but all I got was
> the power to flicker a couple of times. The battery is brand new so
> that shouldn't be the problem. I don't have the money to go take it to
> a shop and get reamed so I want to try and fix it myself. I think
> maybe the power is shorting into the frame somewhere, but I don't know.
> Anyone have any advice for me? thanks in advance.
> -Joe

On the older bikes, where you could Switch Off the headlight during the
day: SOME of these switches ALSO
switched off one of the legs of the alternator. (3 down to 2). This is All
Before the Fuse Box. If the wire
going from the alternator, up to the switch, and then back to the regulator
gets the plastic rubbed-off (time & wear)
then you get a 85vAC to Grounf SHORT, which will eat the windings of the
stator. Needless to say the battery
doesn't charge either.
Quick Check for a dieing battery. If the Turn Signal comes on, but
doesn't BLINK, your battery is LOW (10 volts or less)
and you should head home - to a shop Quickly. If You Can, turn off the
headlight to reduce the load on whats left
in the battery. (Leave for the spark plugs)

On ANY older bike thats 'brought back to life' cleaning the connections
on all of the electrical system will get rid of
a LOT of problems. Dirty connections cause a voltage loss/generate waste
heat. WD-40 works good, steel wool or a
file works better. Look for a paste at an ELECTRICIANS SHOP that
reduces/prevents corrosion on exposed
wires/connections. (NO-ALLOX is one) It only takes a paper-thin layer to
prevent your connections from rusting.

On the HONDA motorcycles. The 'START' push button has 4 wires going to
it, all the same size. (18 gauge or so)
TWO of the wires pass current to the solonoid, to 'key' the solonoid, to
pass current to the Starter-motor.
The Other Two wires pass current to the HEADLIGHT. ADDING LIGHTS will
increase the current, and possibly
melt the plastic inside the switch, shutting off your headlight. Honda
DOES NOT sell switches, just 'wiring assemblies'. (Can you say $100+)
Cheap Fix: Open up the assembly where the start switch is, unbolt the
switch from the assembly. DO NOT UNSOLDER ANYTHING!. Look Closely at the
switch, see that the board with the wires is Pressed Into the plastic that
makes up
the rest of the switch. CAREFULLY Pry the 'teeth' back, be ready for the
ball-bearing on a spring, and open the switch up. Clean the plastic off
the switch contacts, then put it all back togeather. thats it.
Better Fix: Get a Normally Open relay that will continously handle 10
Amps of current. (120 watts) Put this relay
in the electrical box under the fuel tank. Run a wire Directly from the
Fuse box (power in), and another Directly
to the (HI/LOW) switch on the handlebars, and then 2 wires down to the
headlight. Use the current coming through
the START switch to Key the Relay. Now, you have the Headlight Current
going through the relay, Not the Switch.
The amount of current to Key the relay is maybe 5% of what it was before.
With 12-gauge wires for the headlight,
you can run 100 watt lights & not be concerned.

Look for Ground Connections. Clean them. Look for 'ground return'
wires, and either shorten or remove them and use Chassis Ground. (Some
headlight domes use rubber insulators to reduce vibration. Install a
jumper-wire to the bike frame)

Cheap Crimp-connectors: MANY bike's wiring harnesses use these at
connections. They Will Corrode & Open-up over time. Get Out your
Soldering Iron, some cleaning flux, and electrical tape. SOLDER all of the
connections you can.
(Be Careful Around the Blinker Relay/Solonoid/Ignition Control unit/Ignition
pick-ups) Remove what wires you can
from the bike before soldering if you can. Cooking a circuit board is a
real possability - be careful)

Have you got your winter project planned? Good Luck, Lefty


P.S. IF you have a COOKED STATOR, try to re-wind the unit yourself.
Get some transformer wire from an electrical shop, some epoxy to seal it up
wen your done, and COUNT THE WINDINGS as you un-wrap the posts. New
stators run $150+, you can easily save $100.


From: rugger81 on 10 Aug 2006 08:39
Looks like I got some work ahead of me, but at least I have some ideas
of what to do now. Thanks alot guys.

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