Quick electrical Diagnostic Opinion

[Anonymous]

Thanks to those who helped me on my last posting. I have a 1981 GS550 that is not getting any sparks (i have new plugs). I 've done a few tests and here are my results

Resistance at the Signal Generator is 60k

Resistance into both Coils is 3 ohm

Resistance at the plugs from the coils is 33 K and 50 k on the other

is the 50K way out of spec? I was told between 30-40 was good.

Now voltages.... my voltage at the battery as 11.5 V

Voltage to the 33K coil was 11.4 V

Voltage to the 50 K coil was 10.2 V

I'm thinking that I have one bad coil, and maybe a bad connection somewhere between the ignitor and the coil. My understanding is that the voltage at the coil should read close to what the battery reads. Any opinions? Did I miss something? Appreciate your help. THanks!

-skm

[robben]

My specs on the GS550E of '84 read that the low side of Ohms resistance on the coil should be between 3 and 5, and the high side (at the plug caps) should be between 30K and 60K. These are readings taken off the coil, wires taken off the low tension side, and spark plugs disconnected for a reading on the secondary HT leads in the caps. (Coil resistance measurement)

12V battery should be putting out at least 12.4 or so, I am thinking. Is it an older battery?

Robben

[Anonymous]

Actually the battery is a few weeks old... I lost a bit trying to start it. i've been messing with the bike for 3 weeks cleaning out the carb and doing various other things to try and get it to start. I think with all the trys and leaving the ignition on I may have lots a little voltage. I"ll charge it up again.

i was just surprised my other coil was so much different. Most of the postings I have seen say between 30-40. But If it is 30-60 I guess the coil is okay. Also the voltage at the coil I thought was suppose to match the battery. One coil matches the battery but the other doesn't. I think I may have a bad connection somewhere. but that doesn't explain why I get no sparks anywhere. Anyone know a good test for the ignitor? Thanks

skm

[SqDancerLynn1]

Sometimes there is a loss of voltage if the ign switch has bad contacts. Recharge the battery and recheck the voltage. if it get down to 10V or so at the ign module it may not run. A GOOD fully charged battery is a must. If it has the old plugs I would also change them, if they are new I would take them out and clean them

[nert]

Lower voltage at one of the coils may not be a problem, if the igniter is performing its job and completing the primary circuit to ground. If that is the case, it will draw down the B+ potential at the feed side of the primary windings. Remove, the igniter wires "-" from your coils and check the battery voltage at the "+" terminals of your coils and see if they are not the same.

Next step: remove spark plugs from engine, attach to spark plug wires, lay the plugs on the cylinder head so the plug "case" is grounded. With the igniter wires still disconnected from the coil. Turn the ignition on, use a length of wire attached to ground and repeadidly touch it off and on to the coils "-" terminal. You should see a spark at the spark plug, and a small flash at the "-" terminal as you make and break connection. If you do coils are working, at least enough to make an engine run.

check this first, and reply back. then we can talk about the igniter.

[Anonymous]

Excellent,

Thanks for all your tips. I tried everything and looks like the coils are good. i finally started seeing sparks from the plugs so I tried to start her up and after a slight throttle cable adjustment she idles fine. Looks like the electronics are in tact thankfully. I think the problem was some dirty connections and making sure the battery was completely charged over night. I appreciate your help. Now it's off to fix the tachometer cable.....

skm