1981 gs650g no spark on 1&4

[Goon trot]

first off i would like to say thanks for any help, its always appreciated.
i have yet to see this bike run, i got it as a project. both coils spark if i swap the connectors, the ohms on the coils are in spec. the signal generator ohms are in spec according to the Suzuki service manual. i think the ignitor isn't sending signal to the coil. i tested the coil connector wires with a test light, and with the key off they all have power, with the key on only the working coil will get power (flashes when hitting the starter like it should) i was looking at the dyna s ignition system but could not find one for this model, the closest one i could find was the dyna s ds3-2 (550/750/850/1000/1100 Four Cylinder (ND) 1977-1981) says nothing about 650s if anyone has ever used one please let me know if it will work.

i don't know for sure if i need to replace the ignitor, so if anyone has any other tests i could run or any other suggestions that would be great.

i heard that the dyna s is a good choice for a replacement, but i noticed from any pictures of the dyna s that there is no ignitor unit, and was also wondering if anyone knew that it does replace it or not.

[tom203]

The dyna ds3-2 will work.... you have to make cutout in the dyna plate to clear oil sending unit. The dyna replaces the stock ignitor and signal coils altogether. See pic

As further test, make sure you clean the 4 way connector that connects the ignition coils to the ignitor (under seat) - maybe the feed to 1&4 is dirty. The 650 shafty ignitor is very robust , so doublecheck connections. Swaping the feed at ignition coils proves the coils are good.


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[Goon trot]

thank you for the fast response! I will double check the connections, I already cleaned them all but it wouldn't hurt to put a dab of dielectric grease... i'm sure they could use it after sitting for 10 years.

[Guest]

first off i would like to say thanks for any help, its always appreciated.
i have yet to see this bike run, i got it as a project. both coils spark if i swap the connectors, the ohms on the coils are in spec. the signal generator ohms are in spec according to the Suzuki service manual. i think the ignitor isn't sending signal to the coil. i tested the coil connector wires with a test light, and with the key off they all have power, with the key on only the working coil will get power (flashes when hitting the starter like it should) i was looking at the dyna s ignition system but could not find one for this model, the closest one i could find was the dyna s ds3-2 (550/750/850/1000/1100 Four Cylinder (ND) 1977-1981) says nothing about 650s if anyone has ever used one please let me know if it will work.

i don't know for sure if i need to replace the ignitor, so if anyone has any other tests i could run or any other suggestions that would be great.

i heard that the dyna s is a good choice for a replacement, but i noticed from any pictures of the dyna s that there is no ignitor unit, and was also wondering if anyone knew that it does replace it or not.

The benefit of the search function!

Hi from New Zealand, I’ve just joined the forum to get some help renovating my 1981 GS650G. Currently diagnosing an issue with no spark on 1 and 4. Swapped the connectors to the coil and hey presto it worked… the same issue!

Given the age of the wiring, signal generator, ignitor and coils, combined with evidence of some dodgy repairs, I have decided to replace the entire ignition system. Searched the Dynatek site but found only coils are available for the 650. However the Dyna S was recommended for other GS models! I emailed customer service and they confirmed this was the case.

Great to see others have successfully fitted a Dyna signal generator. I see the Dyna ds3-2 can work. Anyone know if the Dyna S or another option can also work?

Thanks for your help