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 Post subject: 1979 RM 250 CDI problems
PostPosted: Sun Mar 28, 2010 1:43 pm 
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Joined: Wed May 23, 2007 12:37 pm
Posts: 15
I just had a 2nd cdi fail on my RM 250. It runs perfectly otherwise, but after having one go bad, the second failed after 30 minutes of riding. Does anyone know if there could be something else in the electronics that might cause this, or do I just have bad luck? Any help would be appreciated.

Clint


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PostPosted: Fri Apr 02, 2010 8:02 pm 
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Joined: Sun Nov 30, 2008 12:10 pm
Posts: 1010
Location: Connecticut, USA
Clint,

It could be the input voltage(s) from the stator are too high, or possibly the coil has degraded and is burning out the CDI output switching thyristor/transistor.

You'll need a really good multimeter to test the stator voltages (they're very short duration spikes) and coil input resistance (the coils I've measured have been pretty low resistance).

Ray

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'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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PostPosted: Sun Apr 04, 2010 6:50 pm 
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Joined: Wed May 23, 2007 12:37 pm
Posts: 15
Ray:

Thanks for the input. Due to my frustration, I spent the money for the PVL ignition system. I just didn't want to continue to mess with it plus most of the testing was over my head. So, I spent the money and it runs great!!

Thanks again,

Clint


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PostPosted: Mon Apr 05, 2010 8:09 am 
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Joined: Sun Nov 30, 2008 12:10 pm
Posts: 1010
Location: Connecticut, USA
Clint,

Quote:
I spent the money for the PVL ignition system

That's what I should have done with my Hondas! Instead, I just kept buying stuff off eBay, now I'm having a rotor remagnetized to try and eliminate a weird idle problem... it just goes on and on. For the most part the bikes run well, but I'm sure they would run better with the PVL unit.

Ray

_________________
'74 CR125M (175cc), '75 MR175, '82 RM250Z, '08 YZ250F, '14 Zero FX electric, '14 Zero MX electric, '18 Alta MXR electric


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