Author Topic: 77 Cb75o F magic button issue  (Read 1508 times)

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Offline 78whiteorbs

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77 Cb75o F magic button issue
« on: July 15, 2012, 05:17:20 PM »
OK , fully charged battery  she fires as she should with a tickle of the button. Ride around a bit and have to kick it to start it back . generally one kick and so easy but still  :(  tested voltage and it is still above 14 when   havin non start condition from the button. What should battery read wile running ?

Offline Gregorymoto

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Re: 77 Cb75o F magic button issue
« Reply #1 on: July 15, 2012, 06:07:26 PM »
How old is your battery?
Yep, i have issues with this sort of stuff.

bollingball

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Re: 77 Cb75o F magic button issue
« Reply #2 on: July 15, 2012, 06:48:31 PM »
Plenty of information in the FAQ section read through the charging part under electrical.
Ken
I.   Initial inspection.
A.   Charging system fuse check
1.   If open replace.
2.   If shorts again search for short circuit.
 
II.   Full load test.  (Determines battery condition).
A.   Turn ignition and high beam on while bike is not running. 
B.   Test battery voltage. 
C.   Voltage bellow 10.5V means battery needs service. 

III.   Charging the battery. 
A.   If specific gravity of any cell is less than 1.230 battery has low charge.
B.   If sediments in battery are touching bottom of any plates replace the battery. 
C.   If specific gravity varies more than .050 then replace battery. 
D.   If fluid level is low add distilled water only.  Don’t add too much as level may rise even more while charging. 
E.   Charge the batter at no more than 10 percent of its amp hour rating. 
F.   If battery temp. is more than 113 degrees F allow it to cool then resume charging. 
G.   If specific gravity of any cell will not charge above 1.230 then replace the battery. 
H.   Put the fully charge battery back in the bike and do the full load test again.  A running RPM test cannot be done unless you have a fully charged battery.  If the voltage is above 12V then you can do the RPM test.
I.   Start the engine and lock the throttle when the RPM is above 4000.  If the voltage is between 14V and 15V the system is fine and the battery was to blame.  If not you have more work to do. 

IV.   If @ 4000 RPM the voltage was bellow 14V…
A.   Check for problems. 
1.   Corroded, loose, or mismatched wires.  I.e. orange and green wire plugged in to each other. 
2.   Modified or non-stock systems.
3.   Visibly damaged wire insulation.
B.   Do a system analysis resistance test. 
*.  NOTE 0 resistance = good wire. 
*.  NOTE infinite resistance while grounded to frame = good insulation.  Coils will automatically have resistance.



C.   Resistance testing of regulator wires. 
1.   While the bike is not running disconnect (-) battery lead and Black regulator wire.  Check for 0 resistance between (-) battery wire and Black regulator wire.
2.   Disconnect all regulator leads. 
a.   Test for resistance between I and F poles.  0 resistance is good.  If greater than 0 clean the regulator points. 
b.   Test for resistance between the white wire and ground.  Resistance between 4 and 8 ohms means the field coil is good.
   
V.   Testing the stator yellow leads. 
A.   Test wires 1 and 2, 1 and 3, 3 and 2 for ohm readings.  Less than 1 ohm means the circuit is good.  Greater than 1 ohm means poor connection.  Infinite resistance means that the coil has an open circuit or possibly a bad lead. 
B.   NOTE.  For GL1000 you need to disconnect/remove the permanent magnet rotor before continuing.  Set tester to insulation resistance and calibrate it to 0 to perform a wire insulation test on the stator.  Ground the negative test lead and touch the other lead to each of the three stator wires.  If the resistance is infinite then the coil is ok.  If not then the coil is shorted to ground. 
C.   Test the three stator wires in the harness of the motorcycle.  First disconnect the rectifier.  Set the tester to resistance.  0 resistance means all three wires are fine.  Greater than 0 means the wire is bad. 
D.   Check the wires for bad insulation.  Connect the black tester lead to ground.  Each wire should have infinite resistance.  Greater than infinite resistance means the wire has bad insulation. 

VI.   Check the five leads on the rectifier. 
A.   To perform a forward bias test first connect the red tester lead to the green ground lead. 
B.   With the black tester lead test all three yellow wires. 
C.   Resistance must fall between 5 and 40 ohms. 
D.   To perform a reverse bias test connect the black tester lead to the green ground lead. 
E.   With the red tester lead test all three yellow wire. 
F.   Resistance must be greater than 2000 ohms. 
G.   Connect the black tester wire to the red and white rectifier lead. 
H.   With the red test lead test all three yellow wires. 
I.   All three must have between 5 and 40 ohms. 
J.   Connect the red test wire to the red and white rectifier lead. 
K.   Test all three yellow wires with the black tester lead. 
L.   Resistance must be greater than 2000 ohms. 

VII.   Testing the harness plugs and leads. 
A.   Test each of the plug wires in the circuit for o resistance. 
B.   While the battery and rectifier are disconnected test the red and white harness rectifier wire to the (+) battery lead for 0 resistance. 

VIII.   Regulator bench test. 
A.   Remove regulator cover. 
B.   First check the core gap to be sure it is between .6 and 1mm. 
C.   Next check the points gap to be sure it is between .3 and .6mm.
D.   Clean the points with contact cleaner. 
E.   Note the 350F points gap is not adjustable. 
F.   Test the regulator leads by first placing paper on both sides of the points contacts. 
G.   Test resistance between I and F, then I and E terminals.  Check you manual for model specific resistance readings. 
H.   Test for 0 resistance at regulator points connections.
I.    While the points contact is in the upper position test between I and F. 
J.   While in the lower position test between F and E. 
K.   Note.  Do not file the points or they will quickly pit when used again.
 
IX.   Perform RPM test again.  Be sure all components meet specks before going forward from here. 
A.   Reconnect all components but leave the regulator cover off. 
B.   Start the bike and lock the throttle at 4000 RPM. 
C.   The voltage should read between 14V and 15V. 
D.   If voltage is low unlock the adjuster screw nut and turn the IN. NOTE do not run the screw into the coil winding or short the screw to something else with the screwdriver.   
E.   If voltage is high adjust the screw OUT. 
F.   For the 350F bend the arm up for and increase in voltage or down to decrease. 
G.   Replace the cover and test the voltage again as the cover can have an affect on the field of the coil. 
H.   GO FOR A RIDE!

Offline 78whiteorbs

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Re: 77 Cb75o F magic button issue
« Reply #3 on: July 16, 2012, 01:20:57 PM »
Wow, thanks. Alot of ammo there.
The battery is a sealed type and looks to be expensive one but I do not know how old it is for certain. Tests fine and Holds 14.5 volts then when I crank here and she is running  drops to 14.15 volts . I was under the impression that the volts were suppose to rise when the bike was running above a certain rpm range. I have a hard wired headlight that is a modern h4 bulb in it . The bike had some custom work done to it so it's a little different testing everything. I havent ridden it very far as I dont want to get stranded with a 500Lb plus bike. Guess I could do a million laps around the block .....till something happens....

what should the voltage be when running  at the battery? Wondering if I have a bum charging system or if the headlight might be to strong or something .
« Last Edit: July 16, 2012, 01:22:55 PM by 78whiteorbs »

Offline Pat_at_APE

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Re: 77 Cb75o F magic button issue
« Reply #4 on: July 16, 2012, 01:23:34 PM »
Do you have it in neutral?  My 77 CB750F will only start by the button when in neutral.  The clutch switch is currently not installed. 

Pat

Offline 78whiteorbs

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Re: 77 Cb75o F magic button issue
« Reply #5 on: July 16, 2012, 01:31:03 PM »
Yes, I did find that out last night thanks, Tried starting it after a charge and it wouldnt then proceeded to kick it almost off the sidestand onto the floor because it was in gear.
Who has ever done that one ? I have only dropped a bike twice and it was from trying to start it in gear from the kick starter. You'd think I would learn...

The voltage does not go up when I revv it though . Is a that a sure fire sign of a charging problem?

Seems like it should .

Offline Pat_at_APE

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Re: 77 Cb75o F magic button issue
« Reply #6 on: July 16, 2012, 01:47:27 PM »
When you press the start button and it doesn't start, is the headlight dimming? 

Pat

Offline 78whiteorbs

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Re: 77 Cb75o F magic button issue
« Reply #7 on: July 16, 2012, 02:33:48 PM »
Nope- no dimming.
no clicking nothing . But then smooth as butter it kick starts first try easy.

Gonna check the headlight and see if it has to big a bulb today . Was reading no more than 50-55 watts or the stator would never keep up.
also read this :

"Charge your battery and then hook it up. Start the bike and hook up a multimeter. rev the bike over 2K rpm and see what the voltage reads. Over 2K it should be generally at least 13.5 - 14.5 volts."

my battery reads 14.18 when it is running but it doesnt spike any when revved   hmmmmIf I road it for a coupla miles I think I would know for sure whats up.
If it kept getting lower and lower then no charging-

Hoping some idiot just put way to big a bulb in it .

Offline Pat_at_APE

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Re: 77 Cb75o F magic button issue
« Reply #8 on: July 16, 2012, 04:22:21 PM »
My bet is your issue is with the starter safety system.   No dimming means no load on the battery!!!  It's not your battery.  It's either the neutral switch or the clutch switch cutting off your starter circuit so you don't start the bike in gear.

Pat

Offline Spanner 1

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Re: 77 Cb75o F magic button issue
« Reply #9 on: July 16, 2012, 04:38:36 PM »
Start button IMO....even with the safety stuff good or bad the headlight must go off when you push the start button . The switch casing gets brittle ( heat+ years ) and cracks apart allowing the sliding contact to stay connected to the headlight contact when pushed and not make the start ( solenoid energised ) connection.......
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline 78whiteorbs

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Re: 77 Cb75o F magic button issue
« Reply #10 on: July 16, 2012, 06:05:56 PM »
Interesting
Why  would it start with a fresh charge though consistantly every time if it were the clutch/neutral switch?.

bollingball

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Re: 77 Cb75o F magic button issue
« Reply #11 on: July 16, 2012, 06:09:59 PM »
For sure the headlight shut off is not working. Your voltage does not seem to be droping at idle with H/L on the voltage should drop
I have a hard wired headlight Can you explain this?

The voltage does not go up when I revv it though . Is a that a sure fire sign of a charging problem? Looks to me like it never goes down enough.

my battery reads 14.18 when it is running but it doesnt spike any when revved   hmmmmIf I road it for a coupla miles I think I would know for sure whats up.
If it kept getting lower and lower then no charging-

 The 14.8 is enough to keep the battery charged. I'm thinking your regulator is not shutting off. Plus the starter safety circuit is not working correctly. Has it ever worked right while you have had it?
 Make sure it is in neutral and jump over your start button see if the light goes out and the starter works
 Do you still have the diode plugged in on your bike?
I think you have (2) problems. Start button and regulator.

Offline Spanner 1

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Re: 77 Cb75o F magic button issue
« Reply #12 on: July 16, 2012, 06:39:07 PM »
Disregard my post if your headlight is 'hard-wired'..... your kinda on your own if you have custom wiring :(
Don't think anyone can help if they don't have the actual wiring diagram as installed on your bike, otherwise just quesswork.... ;)
BTW... if you have an aftermarket reg/rect. ( 'solid state') then it will always read 14.5-14.8V irrespective of RPM's as it works in a different manner than the stock unit .
If your sure it's a carb problem; it's ignition,
If your sure it's an ignition problem; it's carbs....

Offline 78whiteorbs

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Re: 77 Cb75o F magic button issue
« Reply #13 on: July 16, 2012, 06:46:15 PM »
good to know thanks Spanner1-