Author Topic: 76 550 - No power  (Read 3516 times)

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Offline evo42

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Re: 76 550 - No power
« Reply #25 on: August 06, 2013, 08:31:49 AM »
It read 12.6 out of the box.  It's reading that now after a night on the tender. 

Offline Bankerdanny

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Re: 76 550 - No power
« Reply #26 on: August 06, 2013, 09:32:43 AM »
As I understand it, the initial charging process has a chemical impact on the lead plates that provides longer life and improved ability to retain energy. The ability to sustain a heavy draw during the starting process is just as important as the resting state voltage.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline evo42

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Re: 76 550 - No power
« Reply #27 on: August 06, 2013, 12:35:57 PM »
I pulled the cover off the kill switch, it looks pretty good.  I have power at the switch, 10.9v.  I also checked the blk/white wire in the bucket and I have the same 10.9v there now.  Battery is at 12.2v after some attempts at the starter button. 

I've included some pics of the kill switch off and on.  doesn't look like it changes much. 

Offline TwoTired

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Re: 76 550 - No power
« Reply #28 on: August 06, 2013, 02:39:19 PM »
The kill switch's job is to interrupt the black wire 12v to the Blk/wht when set to off.

I would want an explanation of why 10.9V is measured at the Kill switch when the battery reads 12.2V.  Where is the voltage difference going?

If we are to help you, you must state where you are placing your probe tips when making a measurement.  And what state/position your switches are placed during the measurement.
You can make electrical measurements of the switches to determine integrity without taking them apart.
The wire diagram is used like a road map to determine electrical pathways.  The voltmeter probes can then check the roadways to determine if voltage is being correctly routed.

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

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Offline evo42

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Re: 76 550 - No power
« Reply #29 on: August 06, 2013, 06:53:25 PM »
Thanks - the pictures are labeled on and off, that's in reference to the kill switch position. I'm simply putting the red probe on the metal up in the switch, not the black wire shown and putting the black probe on the frame.

I'm getting that 10.6 at the black wires at the coil and in the bucket. 

I too am wondering where the volts are going. Maybe due to old wires or dirty connections somewhere on the bike. 

Still reading and looking at the diagrams.  It's a little frustrating that a full 12.6 is needed. I'm not expecting a perfect running bike but just trying to get it to run (like garbage) is the goal.

I'm going to move to valve adjustment.  I refurbed the tank with por-15 and installed new fuel lines. I'll do carbs last.  I'm getting fuel out the overflows so I'm assuming its getting gas. 

I'm not an expert at motorcycles so I appreciate the help.

Offline TwoTired

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Re: 76 550 - No power
« Reply #30 on: August 06, 2013, 10:43:20 PM »
Thanks - the pictures are labeled on and off, that's in reference to the kill switch position.
The pictures show no representation of electrical connections.  How would we use that info?

I'm simply putting the red probe on the metal up in the switch, not the black wire shown and putting the black probe on the frame.
The metal that you see in the switch housing may be a black wire connection or a Blk/wht wire connection, (or even neither).  Unless it is taken apart, you are only guessing.  And, as I said before, you can check switch function by measuring from the wire ends that ultimately connect to that switch.  You don't have to take it apart until testing shows it isn't doing what is expected of it.

While you can use the frame as a grounding point for testing, it isn't reliable until verified as having good connectivity to the battery NEG terminal.
Electrical troubleshooting is the elimination of unknowns or the accumulation of knowns.  If you can't keep the list in your head, then write down what is known or what isn't.  If you are just learning, make a copy of the wire diagram, and write your notation on it as you do the probing.  Assumptions can leave you chasing your tail for days, even months.  BTDT

I'm getting that 10.6 at the black wires at the coil and in the bucket. 
I'll take a guess that the main key switch contacts are worn/dirty.  Presently that is an assumption based on the limited data collected.  But, that can be verified or eliminated as a possibility via measuring at points before and after the contact connection path of the switch.

I too am wondering where the volts are going. Maybe due to old wires or dirty connections somewhere on the bike. 
Seems likely and is often the case with components that have been in service since 1976.

Still reading and looking at the diagrams.  It's a little frustrating that a full 12.6 is needed. I'm not expecting a perfect running bike but just trying to get it to run (like garbage) is the goal.
12.6 volts is the voltage for an unloaded battery at full charge.  When loads are placed on the battery, it's voltage will fall in relation to the magnitude of the load.  The alternator's job is to restore that voltage once it is spinning fast enough.  If you just want to hear the motor run you can connect the Blk/Wht wire to the battery POS terminal and kick start the bike, assuming all else is is working order.

I'm going to move to valve adjustment.  I refurbed the tank with por-15 and installed new fuel lines. I'll do carbs last.  I'm getting fuel out the overflows so I'm assuming its getting gas. 
Getting gas out the overflows does not mean gas is being delivered to the cylinders for firing.  That is a separate verification operation.


Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

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Offline evo42

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Re: 76 550 - No power
« Reply #31 on: August 07, 2013, 08:54:30 AM »
I appreciate all the feedback and your patience. 

I'll use the neg battery terminal to ground on future testing and perform the switch test correctly.  I'll clean the connections off the wiring harness for the ignition key.  The ignition key unit is brand new, I ordered and installed on the bike two weeks ago. 

Heading out for tappet feeler guage, I need an 'electricity' break...



Offline evo42

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Re: 76 550 - No power
« Reply #32 on: August 07, 2013, 11:38:02 AM »
Hadn't tried to start it until a few weeks ago.  Thats when I noticed the original ignition key unit had lost its wires at the back of the unit. 

Offline evo42

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Re: 76 550 - No power
« Reply #33 on: August 07, 2013, 03:08:21 PM »
I completed the valve/tappet adjustment using Socomoto's youtube video.  I noticed while turning the motor on the points side with a socket that the 1-4 points weren't opening and the 2-3 barely opened.  I did this both without power and again with key on with kill switch at run.  Order a new plate/points and condensor?

I'm starting to get suspicious of the spark plug wire splicing I did.  I used the ngk splicers but maybe I didn't get the connections right.  I'll probably redo those as well as the new angled plug boots I installed there. 

Offline TwoTired

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Re: 76 550 - No power
« Reply #34 on: August 07, 2013, 03:33:13 PM »
I completed the valve/tappet adjustment using Socomoto's youtube video.  I noticed while turning the motor on the points side with a socket that the 1-4 points weren't opening and the 2-3 barely opened.  I did this both without power and again with key on with kill switch at run.  Order a new plate/points and condensor?

Replace?  You will have to go through the points adjusting procedure either way.  Why not practice on the points you have now?


Find high point of point cam (max point gap) and adjust it for .014" gap.  Do this for both point sets.
  Then adjust static time by rotating the main plate so that when the 1-4 point set just breaks contact, the F mark aligned at the same time.
The 2-3 points are adjusted similarly, except they have their own plate to move on top of the main plate and they use the 2.3 F mark rather than the 1.4 F mark.

The adjust procedure is outlined in the shop manual.

Edit: oops, mistyped T instead of F.  Must proof read better, I guess.  But, it's tough when typing the same procedure multiple times.
« Last Edit: August 14, 2013, 04:10:08 PM by TwoTired »
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

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Offline evo42

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Re: 76 550 - No power
« Reply #35 on: August 07, 2013, 04:52:21 PM »
Ah, thanks for the tip TT.  I'll do this in a bit and report back.

Offline evo42

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Re: 76 550 - No power
« Reply #36 on: August 14, 2013, 02:12:00 PM »
I've done the points gapping and have both 1-4 and 2-3 points opening just as the F mark hits the mark for both 1-4 and 2-3 rotations.  I have a test light but its a one-clamp gator with a prod so I'm unable to get the light to come on.  Going out to pick a two-clip light for final testing. 

I don't have a timing mark on the plate that I have, I'll have to use the light to determine if I have the timing correct. 

Offline Bankerdanny

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Re: 76 550 - No power
« Reply #37 on: August 14, 2013, 03:18:43 PM »
You want the points opening fully at T, not F. F=full advance, T= top dead center.

The F position is where the points should be opening when the engine is spinning at about 3k rpms. If you adjusted the plate to open fully based on F then the points are opening too late.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline TwoTired

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Re: 76 550 - No power
« Reply #38 on: August 14, 2013, 04:17:41 PM »
You want the points opening fully at T, not F. F=full advance, T= top dead center.

The F position is where the points should be opening when the engine is spinning at about 3k rpms. If you adjusted the plate to open fully based on F then the points are opening too late.

You might want to edit this after reviewing the shop manual.  The T and F marks are static time adjustments or Fire at idle; TDC and Fire.  There is a separate index mark 23.5-26.5 before F for full advance using the strobe above 2500 RPM.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

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Offline Bankerdanny

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Re: 76 550 - No power
« Reply #39 on: August 14, 2013, 08:03:07 PM »
As usual you are correct. I was mixing up instructions related to my GL1000 with those for the CB550.
"The problem with quotes on the Internet is that you never know if they're true" - Abraham Lincoln

Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline evo42

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Re: 76 550 - No power
« Reply #40 on: August 23, 2013, 09:46:15 AM »
New points and condensors installed.  Theyre gapped and both open on the F marks on each 1-4/2-3.  Sanded every power and ground wire I could touch.  Sanded the fuse box again.  Brand new correct size main fuse from dealer installed.  New starter solinoid installed.  Those wires sanded too.
Power at battery with key/switch off is 12.42.  With just key on its 12.25.  Add the kill switch to run and its 12.15.  Power at coils is 10.8 with key and switch on.  I opened the starter and a pile of black poweder fell out.  I have yet to clean the brushes. 

I really need to check for spark and test the coils.  Chasing my tail, losing interest.

Offline evo42

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Re: 76 550 - No power
« Reply #41 on: August 23, 2013, 11:08:32 AM »
Ive got spark at all four plugs during kick-start.  Enough spark though?  I didn't like the results of my primary and secondary coil tests.  Buying another multi-meter tonight and will re-test.  Testing primary at blue and black wires from coil, measuring ohms at 200 switch.  Using blue wire and #1 plug for secondary test at 20k switch.

I'm also going to pick-up a compression tester.  I drained all four bowls, a good stream of clear gas came out of each, no chunks or gunk.  I understand I'll need to clean the carbs shortly but again, just looking for some hint that this thing will run.

Moment of desparity gone...for now...

Offline TwoTired

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Re: 76 550 - No power
« Reply #42 on: August 23, 2013, 11:39:30 AM »
The coils are internally connected from black/wht to blue (or yellow) inputs.  And the output (spark) leads are connected together internally.  None of the input leads should connect to any of the output lead.
Expect 5Ω on the coil inputs, and about 15KΩ on the output leads.

You say you have spark, so they are probably ok.  But, none of your measurements support that conclusion.

10v at the coils isn't very good, and indicates your bike's wiring, connectors and switches are losing 2V along the route.  Something along that path needs reworking.  But, should still allow the engine to run.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline evo42

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Re: 76 550 - No power
« Reply #43 on: August 23, 2013, 12:19:17 PM »
I used this video to do the coil testing.  I was using the blue wire from the coil and the #1 plug wire to do the secondary testing.  I used the bluew wire and the black/wht wire to do the primary testing.  Maybe those arent the correct wires or this particular test doesn't apply.

http://m.youtube.com/watch?v=rRQ45lT2d3c

Now I'm feeling like its compression related.  I'll check that after I complete the coil testing.  Carb cleaning coming up fast, I hate to spend the money.  I may cheat and try the spray-up-the-drain and hope to get some response other than nothing. 

Thanks again for the feeback...

Offline TwoTired

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Re: 76 550 - No power
« Reply #44 on: August 23, 2013, 03:12:18 PM »
I used this video to do the coil testing.  I was using the blue wire from the coil and the #1 plug wire to do the secondary testing.  I used the bluew wire and the black/wht wire to do the primary testing.  Maybe those arent the correct wires or this particular test doesn't apply.

http://m.youtube.com/watch?v=rRQ45lT2d3c

That video is outright wrong for the SOHC4 coils. The primary measurement is ok.  The secondary test his way will make all SOHC4 coils test bad.
Below is a schematic representation of an SOHC4 ignition circuit, except we have no ballast resistor in stock form.
There is no connection between primary and secondary.  If you test for conduction across the two windings it had better read as an open, as a good SOHC4 coil will do.  Many Cb550 Wire diagrams depict the coil internals schematically.  None of them show a connection primary to secondary.

No doubt among the thousands of coil designs, you will find coils that do make a common connection from primary to secondary.  Most of these are single output coil, I think.  But, coils are not interchangeable across all applications.



Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline evo42

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Re: 76 550 - No power
« Reply #45 on: August 23, 2013, 03:45:50 PM »
Excellent news then!  New ($6.99 at Northern tool) multimeter shows .05 when I touch both probes together.  I do the primary test for the blue/blk/wht wires and it measures 5.0.  Same reading when I do the yellow/blk/wht.  I didn't get a reading when I did the video secondary test so that confirms (not needed, we all know you got this) your statement. 

On to compression test.  I'll kick it until the needle stops moving and report the PSI.  I read the FAQ on this, mine too is a cheap autoparts tester. I'm hoping for 100+ and within 10% of each other...

Offline evo42

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Re: 76 550 - No power
« Reply #46 on: August 23, 2013, 05:11:01 PM »
Compression is 100, 60, 120, 110 (1,2,3,4).  WOT and choke open.  Airbox is in, I'll take it out when I test after squirting some oil.  Read on another site 140 is minimum.  Its rings if compression comes up with oil, valves if no change with oil. 

Carbs coming out this weekend not that I have time.  I'll start looking for next steps depending on the outcome of second round oil testing. 

Offline TwoTired

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Re: 76 550 - No power
« Reply #47 on: August 23, 2013, 06:06:38 PM »
If the engine hasn't run for a while, delay taking drastic action to the motor components.  When sitting rings can stick and rust can form on the valves. Both can make the compression lower.  Run the thing for a hundred miles or so before cracking the engine open.  Most times, the compression comes up with use.  There are exceptions, of course.  Like flood aftermath engine, where only the outside was dried off.   It's very unlikely you will ever get 140 PSI with and automotive tester on a tiny motorcycle cylinder.  The reasons why are in the FAQ.

Also, don't put more than few drops of oil in the cylinder.   The 550 chamber is about 10cc, which is what a tablespoon is in volume.  Reducing the compression chamber will, of course, raise the compression figures regardless of how well the engine parts seal on their own.  This is one reason why many prefer a leak down test over a straight compression test.
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline evo42

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Re: 76 550 - No power
« Reply #48 on: August 23, 2013, 07:24:06 PM »
OK cool, makes sense.  I meant to say 'now' that I have time.  Moving to carb cleaning/rebuild kit now. 

Thanks so much for all the help!



Offline evo42

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Re: 76 550 - No power
« Reply #49 on: August 25, 2013, 10:43:53 AM »
I found i'm running 627b's on my 76 cb550k.  Bowls and carbs looked great except #3 that was cooroded so badly one side of the leaf spring was gone.  Lots of orange in the bowl and on the floats.  I was able to clear the idle and main jets with air and carb cleaner.  They're a little crusted still on the exterior however.

I also noticed the lack of a slow jet on all of the carbs.  Should be down to the left of the main correct????

So #3 needs a rebuild kit.  It feels like I can get away with just cleaning the rest due to the visible condition.  I'll prob need to order the slow jets individually (40s I think).  I saw another post where someone was running this setup and it seemed to work for him. 

Oh yeah, need a new leaf spring too, I'll check ebay and the classifieds...