Topic: Cb550 has no spark. Help please

[Stev-o]

If you are certain the coils are bad, send them to Stev-o, he needs a good working set of original 550 coils for his latest project. 

I do?!    Oh, thanks for diagnosing my issue, Cal!

[Jimsun]

What tests did you run on the coils apart from "replacing" them to determine both were bad? Simply replacing parts until the bike runs correctly again (electronically) is not diagnostic, and in no way insures that you have either identified the problem, or fixed it.

Its quite probable and very likely that in the course of replacing the coils, you corrected a wiring/connection problem to the coils, be it the BLK/WHT power feed, or the ground wires. Could also be a corrective action was taken coming from the ignition plate.

If you are certain the coils are bad, send them to Stev-o, he needs a good working set of original 550 coils for his latest project. 

Ive replaced most electronics and tested them. Then when it started i started putting  everything back. Then when it came to the coils, it didnt run. I made sure there was voltage to the blk/wht. I tested the kill switch the blk wht voltage feed turn on/off. Tested the plug boots. No power. All connections seem right colour to colour. Continuity on both ends. I don't know what im missing

[MoMo]

possibly you are not getting contact at the points.  Have you used electronic cleaner and a fine point file to ascertain that the points are making contact?...Larry

[Jimsun]

... Tested the plug boots. No power. All connections seem right colour to colour. Continuity on both ends. I don't know what im missing

As I said, "how did you test the coils"? There is no power transmitted through the plug boots that you would test. You would test them for resistance. You test the coils differently too. You need to check for 12v at the coils themselves.

I did some test with feeding it voltage and checking for continuity and then stumbled upon this
http://forums.sohc4.net/index.php/topic,5752.0.html

My thoughts are if i replace it, and it works, and i put the old one back and it doesn't work, doesn't that simply mean the old one is no good (technically?). I've replaced each coil, i've swap 1/4 2/3 and it wouldn't run. So when you say how am i 100% sure it's not the coil, i dont know what to say to you.

It's like a single pole switch. It was working but now it's not. You replace it and suddenly the light turns on when the open contact closes. when you swap the old 'broken' one back, the light doesn't turn on. At that point, wouldn't you say the switch is defective or would you say that it's not the switch because proper tests haven't been done to justify that it is the switch?

same with a relay. An NO relay will turn NC when power is fed to the coils. When the contacts doesn't close then it's deem defective. When you replace it and it works again, wouldn't you say that the relay is broken? or would you say that not enough tests have been done to back up the claim.

I suppose i can do a thorough test to pinpoint the exact issue as to why the plugs aren't getting spark. I'lll report back when i go about doing it.

possibly you are not getting contact at the points.  Have you used electronic cleaner and a fine point file to ascertain that the points are making contact?...Larry

Yes i have made sure of that. thanks

[Jimsun]

You could assume that a component is bad when replacing it solves the problem, and restoring it recreates the problem. But, as many have said, it's incredibly rare for 2 of these coils to go bad simultaneously. Replacing/restoring these components involves wiring connections in multiple areas, and I submit (perhaps others also suspect) that during the changes you "fixed" the connections while handling them. But it's possible both are bad.

Since you never posted the results of readings on your coils, nor explicitly answered the tests (other than to say "I did this, and that happened") no one can be assured of the actual problem. And you stated, "I replaced many things and I no longer have the problem..."  Well, hard to accept that as diagnostic diligence.

In the end, if it's working for you, great. How you arrived there is not the recommended approach and many were trying to help you ascertain exactly the cause and solution to save you money and some time.

Yes i did change many things but i returned everything back as i borrowed parts from another bike (borrowed and returned all original parts).

I did follow everyones input and it did not work.

at first i checked the sparks. It was sparking
Then i made sure fuel was going into the system.
compression read 125-130ish across all four.

i drained the bowls and tried again

i put in brand new plugs and reused the old ones after it was running when i replaced the coils.

i fixed the killswitch. that's very simple and not complex. i forgot which wires goes into the kw but i believe it's blk and blk/wht. With a continuity test, it should only beep in the run position - which it did. i even tried by passing it by connecting the blk/wht into the 12v feed.

before i replaced my points, i made sure there was voltage going into the coils by connecting the meter in parallel with the wires that feeds the coil thru ground.  i replaced the condensers with a brand new ones i have at home which again didnt solve it but i placed the old ones back after i found out it was the coils.

i made sure it was in neutral

i replaced the safety starter unit with an assumed working one from a running bike which i took out and put my old ones in once i knew it was the coil

then i swapped 1/4 and 2/3 coils. after that i swapped both coils and boom it started.

from here i started working backwards. I reinstalled my old coils and it didnt start. I put one and it was almost going. then i put 2 working old coils and it started.

After that i started putting all the parts that was originally in the bike back and she's still going.

the only thing to do now is to figure out WHY and HOW both coils went bad at the same time over night.

i will report back when i have time ti diagnos it




 

[Spanner 1]

Guys,  wait now ! What actually happened is that both coils did go bad at the same time ! because he cooked them with that car battery connected !... Look, the 14amp/hr battery in the bike will just deplete with the load of the coils connected to it ( ign. left on for any length of time ).. i.e. the voltage will drop to , say, 9 or 10 volts BUT if you leave the coils connected to a car battery they will continue to draw current and overheat and melt the windings = both coils failing at once.... no other possible cause as it's impossible for the bike battery to supply enough amperage/time to do it.. 

[Jimsun]

Guys,  wait now ! What actually happened is that both coils did go bad at the same time ! because he cooked them with that car battery connected !... Look, the 14amp/hr battery in the bike will just deplete with the load of the coils connected to it ( ign. left on for any length of time ).. i.e. the voltage will drop to , say, 9 or 10 volts BUT if you leave the coils connected to a car battery they will continue to draw current and overheat and melt the windings = both coils failing at once.... no other possible cause as it's impossible for the bike battery to supply enough amperage/time to do it.. 

Hang on, but the bike being hooked up to the battery is really only working the starter not the coils. If you think about it, wouldn't the coils be worker harder when the bike is running at the higher rpm? I really don't see the coils being burnt for just hooking up the car battery. If anything, it will destroy the starter unit or the starter motor itself not the coils. the amps is there and you only use what you need.

even on a fully charged battery, i have never held the electric start button long enough to fully drain the battery. I would crank it for 2-3 seconds and if it doesn't start, then kick start till it goes.

[Spanner 1]

See, if the ignition is 'on' ( in order to use the starter ) then the coils are powered also. If the points are closed then the coils are drawing about 2 1/2 amps each. The bike battery will run down PDQ, especially if the headlight is also 'on'. Not so a car battery, it could supply the headlight and coils all night !! = fried coils as under normal operation they are switching on and off ( by the points ) and are not designed for a continuous powered up deal. 

[MoMo]

See, if the ignition is 'on' ( in order to use the starter ) then the coils are powered also. If the points are closed then the coils are drawing about 2 1/2 amps each. The bike battery will run down PDQ, especially if the headlight is also 'on'. Not so a car battery, it could supply the headlight and coils all night !! = fried coils as under normal operation they are switching on and off ( by the points ) and are not designed for a continuous powered up deal. 

makes sense to me...Larry