coil testing is it possible

hi all

just a quick one can any one tell me how to test a coil an easy way apart from buying heaps of tools any info would be great

thanks john

 

The coil can be checked for resistance. Remove the plug ends that attach to the sparkplug and check the resistance with a multimeter between the High Tension leads. This would be the plug wires on cylinders 1 & 4 for the first coil and 2 & 3 for the second. This is the secondary resistance and you are looking for 11k ohms + or- 20% at 20 deg C. Next unplug the small wire lead to the coil and check the primary resistance between teh wires i the connector there. Looking for 2.5 ohms + or - 10% at 20 deg C.

 

I do the resistance check and run the coil on a valid system with a $10 spark checker from Harbor Freight.

 

Untecho test , coil on bench [or in bike] , put in sparkplug , earth sparkplug outer with wire to center steel thing in coil , next , wires from a battery to the 2 small wires to the coil BUT only flash one wire [a real quick touch] and if it ok it should spark at the plug.

This is a guess , but it something like that , do not leave the 12v wires both attached , fix one [say negative] and flash the other [positive].

AND keep the fingers away , i hate that when it happens :cry:

 

I've checked all my coils, it's easy. I was disappointed to find how weak the stock coils are. I'm using a special tester that generates the signal to fire the coil but you can do it on the bike with the engine running if you get a spark tester at the auto parts store, not the neon light one, but one with an adjustable spark gap. You can adjust the distance the spark will fire to see how far it can jump. Some of them are also calibrated in KV but I doubt that's very accurate. I found the stock coils would produce a spark that jumps about 1/4" and looked very weak while aftermarket coils like the Accel and Dyna can make a fat spark that jumps almost an inch.