quick coil question...

[deadchef]

stock 81 with tci.

to check the coil if it's bad, do i just take an ohm reading between the red/white and orange wire? if so, what are the specs?

sorry, looked in the tech section but it still wasn't very clear to me...

 

[nj1639]

Mine ohmed out at 3 plus ohms and works...orange to red/white.

 

[xjwmx]

That looks like an original coil. TIme to replace!

But anyway I had a coil that measured good but was bad. You can't measure pathways inside the coil that have developed that are a high voltage short only. Which is what running without plugs attached is supposed to cause.

 

[deadchef]

Mine ohmed out at 3 plus ohms and works...orange to red/white.

ok, that's what i thought. here is the reading i got...

now with just a hair over no resistance, should this thing even work? the bike runs but shitty as i've documented in another thread...
http://www.xs650.com/forum/showthread.php?t=17925

the reason why i wanted to check the coil is the other day i checked compression and had the plugs out but grounded to the engine. turning over the engine i noticed the spark was there but seemed very weak...

hmm... the plot thickens....

 

[xjwmx]

It's supposed to measure 2 -3 ohms. That's all anybody will be able to say. Except be sure you're using the meter right. I vastly prefer auto-ranging meters. This is the 21st century. It's easy and cheap.

 

[650Dave]

I would replace the coil just based on its age.

I read the entire thread because my 80 was acting in the same way. I went through the carbs several times, found a used TCI box and switched it out, reset valves, etc. Then I remembered that I had replaced the rotor a few months earlier, and someone said that sometimes the magnet that triggers the ignition signal could be weak and cause the symptoms that both you and I have experienced. Of course I overlooked this because I had a new part on there.

I super-glued a small rare-earth magnet from Radio Shack (2.99 or so for two) on top of the magnet on the rotor, and it fixed everything. Someone has already mentioned this to you in your original thread. Have you tried that? Dave

 

[deadchef]

I would replace the coil just based on its age.

I read the entire thread because my 80 was acting in the same way. I went through the carbs several times, found a used TCI box and switched it out, reset valves, etc. Then I remembered that I had replaced the rotor a few months earlier, and someone said that sometimes the magnet that triggers the ignition signal could be weak and cause the symptoms that both you and I have experienced. Of course I overlooked this because I had a new part on there.

I super-glued a small rare-earth magnet from Radio Shack (2.99 or so for two) on top of the magnet on the rotor, and it fixed everything. Someone has already mentioned this to you in your original thread. Have you tried that? Dave

haven't tried the magnet trick yet. just wanted to rule out carbs first. unfortunately (or not) i sent out my carbs yesterday to oldskoolcarbs for him to look over my work so i guess i won't get to move forward with this for another week or so. sucks but what can you do...

 

[resto]

Judging from your second photo, your multi-tester is in the wrong resistance range. You should be in the R X 1 range. Where the needle is sitting now, it could very well be with in limit for coil resistance.