Secondary Coil Busted?

[bud.]

Hi all,

So in diagnosing some possible ignition problems (bike sputters and dies when hot, no matter the RPMs or throttle position), I decided to test out my coil.

Primary side, I got 3 Ω, manual calls for 2.5-3 Ω, looks good.

On the secondary coil, I measured 18k Ω, and the manual calls for 6.32k - 9.48k Ω...

Now I've heard that when you coil's fried, I shouldn't be getting any reading at all... but in this case I'm getting more than 200% more.

Something seems quite wrong, is it my testing?

Thanks in advance for the input everyone!

 

[bud.]

By the way, bike is an '81 SR250, and the plug looks good.

 

[CarbsAndCylinders]

When the secondary coil's resistance is low like that it usually means the coil is shot.

 

[CarbsAndCylinders]

Also when coils start to go bad they can operate properly until they heat up.

 

[bud.]

Thanks C&C - I appreciate the help!

So I should swap it out for a generic 3 ohm coil? I remember reading a post where Kanticoy said 3ohm replacement coils can drain your bike in slow traffic, and to install a headlight switch- any thoughts on that?

 

[bud.]

Here's what he was saying... does that just mean an off switch for the headlight while in traffic?

The dyna coils are great for your bike. You want to put a cut off switch on your headlight though with the 3ohms though because they will drain the bike in stop and go traffic. My 2 favorite ignitions are the PAMCO and the dyna. I run the dyna on my 400f and it couldn't be any easier to use. The PAMCO is a little different in operation, but I have one on my cb125 and it works a treat.

http://www.dotheton.com/forum/index.php?topic=27959.msg299962#msg299962

 

[CarbsAndCylinders]

I''m not sure about that. You could ask Sonrier, he knows a lot about electrical stuff.