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Author Topic: Lost spark on 1/4, how do I test my dyna?  (Read 756 times)

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Offline camelman

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Lost spark on 1/4, how do I test my dyna?
« on: August 16, 2011, 09:00:26 AM »
I lost cylinders 1 & 4 on a dyna equipped 400f. Resistance between one lead and the backing plate is 25 ohms no matter which order I attach my tester probes. The other lead shows infinite ohms in one direction and 25 ohms in the other. Does this definitely mean that the diode shorted in the first situation described above?  Anything else to check before I buy another dyna?

Camelman
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Offline david 750f

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Re: Lost spark on 1/4, how do I test my dyna?
« Reply #1 on: August 16, 2011, 01:55:46 PM »
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Offline camelman

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Re: Lost spark on 1/4, how do I test my dyna?
« Reply #2 on: August 16, 2011, 03:21:19 PM »
That's the procedure I used. Is it pretty cut and dry, or are there any "gotchas"?
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1972 350f rider: sold
1972 350f/466f cafe: for sale
1977 CB400f cafe:sold
1975 CB400f rider: sold
1970 CB750 K0 complete bike: sold
2005 Triumph Sprint ST 1050 rider

We've got to cut it off... and then come down on rockets.  (quoted from: seven minutes of terror)

Offline david 750f

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Re: Lost spark on 1/4, how do I test my dyna?
« Reply #3 on: August 16, 2011, 04:34:12 PM »
No, 'gotcha's" that I know off  ;) ;)

Contact Dyna, their customer service is excellent. They may replace the part even if it is out of warranty.
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Offline chewbacca5000

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Re: Lost spark on 1/4, how do I test my dyna?
« Reply #4 on: August 16, 2011, 05:26:18 PM »
I would just switch the blue and yellow wires to see if you get spark on 1,4 and if you get spark you know your coils are good and the issue is probably the dyna.
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Markcb750

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Re: Lost spark on 1/4, how do I test my dyna?
« Reply #5 on: August 16, 2011, 06:23:09 PM »
FYI

http://forums.sohc4.net/index.php?topic=76709.msg1025941#new

I had a ignition problem also, Dyna could not duplicate and then lack the testing set up to properly duplicate real life conditions.
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