Reviving an1974 Honda CR250

[gaillarry]

Bringing the old girl back to life. New ign coil, points, condensor, magneto. Kick start only, get nice fat spark on the points but nothing at the ign coil.

So I ran a direct wire from the magneto output wire to the HT input on the ign coil. Ign coil is grounded to the frame. No spark, with the ground connection on or off.

I checked the output voltage from the magneto and it's -14-18 volts (depending on how hard I kick it over). Strange I'm getting minus voltage!!!
I have my meter +probe on the output wire and the -neg probe on the frame?

Any ideas what to look for??

 

[2strokerfun]

Here is a post I lifted from www.honda-elsinore.com poster Ray Rivers. These should be close enough close to what you need on the 250. Honda manual is online at this site, but they didn't give electrical numbers in their manuals back in the day. (Your bike has 6 volt system, which I'm sure you already know) Ray is pretty helpful, so if you need clarification, he will respond to a post on that site. Here is the post:

I recently took some readings on my '74 CR125M ignition components. The stator 'spark' winding and ignition coil readings should be close enough to use.

You'll need a good meter - and some unusual settings - to take these readings. I have a Fluke 87 (which I consider a very good meter), and even then I had to pull out the manual to figure out how to set the meter for peak-hold and 1 mS sample time for the voltage readings. It was worth it, though, because voltage readings show actual performance rather than just wire resistance. For the coil input resistance, I shorted the leads and zeroed the meter to remove the lead resistance before taking the reading.

At any rate...

Ignition coil input resistance (red & green or blue/white & green wires) .7 ohms
Ignition coil output resistance (green wire & plug cap) 10,600 ohms (10.6k ohms)
Stator coil output resistance (red wire & ground) 275 ohms
Stator coil output voltage - approx. 140 to 160 peak AC volts when kicked over rapidly
--RayRivers

 

[gaillarry]

Thanks very much, great info !!!