Ignition Coil Rebuild

5 replies to this topic
  • kylepennock

Posted November 17, 2005 - 12:35 PM


I was woundering if i can rebuild my coil... ok maybe not rebuild but attach a new spark plug wire??

Can someone tell me how ? thanx :applause:

  • dorkpunch

Posted November 17, 2005 - 01:08 PM


what is it on? some of them you just have to unscrew the old spark plug wire and then screw the new one on. depends on the bike/stlye though... at worst case youll have to cut the old one out and solder the new one in.

  • Vintage Not Pimpage

Posted November 19, 2005 - 11:36 PM


Take it to an auto electricians.
The coil on my old CR250RF went bad once and a mates old man who was a auto elec had it fixed in no time.

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  • midwestmotocross

Posted November 21, 2005 - 07:35 AM


Speaking of this, I have a coil that gives me a reading of 17k OHMs on the plug end, when spec says it should be 7k...in anyone's experience, could this be just in the plug wire or does that even make sense? The bike is an '81 XT250.

  • Ozboy

Posted November 24, 2005 - 04:56 AM


coils which have a permanent HT wire in a "saddle" on the coil can have the lead replaced by gently filing the plastic away at the far end of the lump until the end of the wire is exposed, then, using a good tool, desolder the wire & pull it out. Test for rsstance of Secondary-abandon if >125% above std. Buy correct diameter HT wire - WIRE CORED, strip abt 1" and twist togther, fully install and re-solder with resin-cored electronics solder, trim off excess wire let cool and coat with convenient blob of Silastic/similar to prevent shorts. Recheck resistance of secondary and primary - should be within 10% of specified.

  • Ozboy

Posted November 24, 2005 - 05:05 AM


my manual says XT250 81

HT coil primary resitance 1.0 Ohms, 15% tolerance

secondary 5.9K Ohms 15% tolerance

Spark plug cap 5K Ohms - NGK labeled so- don't have to use it.

spark plug - resistor type 5K Ohms if used.

17K Ohms- sounds suss to me, but if it runs........

If new afternarket coil chosen MUST be CDI type!!!!!!!!!!!


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