4.0 ohms Primary BUT what is the Max Secondary Coil Reading a GS850 can handle ??

[Guest]

Hi ,I am going to replace my old 1980 GS 850 Coils ,,,The Bike has 2 different colored Coils on it,,
I can buy a S/H set of later model Coils off a DL650 Bike ,
These DL650 Coils read 4.0 on the Primary side ,which is correct and on the Secondary Side they can read between 24 to 37 ,
Would these DL650 Coils work fine on my 1980 GS850 ????
OR
is the Secondary side Reading of between 24 and 37 ohms to high or to Low ????

I have looked everywhere but I can not find what a Standard GS850 4.ohms Coil should read Maximum on the Secondary side ??
Can someone tell me what the Maximum reading on the Secondary side can be ???
thanks for your help ,,,regards Phil

[Steve]

24 to 37K is quite a spread.

Is that measured with the plug caps installed?

The factory service manual specifies 30-40k Ω, measured from cap to cap.
Keep in mind that the caps are 5k Ω each, so a bare coil should be 20-30k Ω.

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[fbody_mike]

My gs550 manual says secondary resistance with caps on is between 30k to 60k Ohms. I'm guessing the large spread is to account for different meters.

[Steve]

What manual do you have?

The Factory manual says that cap-to-cap resistance should be 34-36 kΩ. In Canada, that should be 35-38 kΩ.

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[fbody_mike]

Factory manual for an 83 gs550e.

[Steve]

OK, I missed the point that you have an '85.

30-60 kΩ is good for your 550, but the 850 manual still calls for 30-40 kΩ for the 850s.

Overall, I don't know how much the secondary resistance affects the system. However, I DO know what happens if the primary resistance is a bit too low.

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[phil007]

My Bike is a 1980 GS850 ,, thanks

[Steve]

My response in post #2 still holds true.

This is what happens when others start posting other facts without explaining the relevance.

It would also help if I would notice whose post I am responding to,
rather than just blindly responding to the last post.

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[fbody_mike]

As the other I will explain the relevance. The coils should be measured to the specification from the motorcycle they were original to not the bike they are being transplanted to. The primary is the most important and should match the original and transplanted as much as possible. The secondary side will have an effect on the ignition module as in induces some voltage back on the primary as the field collapses. Nobody really worries about that so just check the resistance against the original specification for the DL650 and if it passes the coils are good.
Again, the primary DC resistance is the important part. Physically fitting the new coils is the other part, the leads need to be long enough, the primary connectors don't short on the tank etc.