How to Test a Motorcycle Coil With a Multimeter
RickTaff
Nova Slayer
Joined: 28 Jul 2016
Karma : 
 Posted: 22:06 - 16 Apr 2017 Post subject: Is there a simple way to test the Ignition Coil? |  |
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| I think my coil may be on the way out as my bike struggles to start even when warm, and cuts out after engine is warmed up; also seems to misfire when riding. Resulting in a stutter, hesitation. Have changed Spark Plug, cleaned carb. But have been advised my symptoms are also those of a failing coil, so is there a simple way to test the coil? Wont have a Multi meter until middle of week, as mine is broke so need to borrow one, have been told of some test which involves removing the spark plug cap from the plug, inserting a screwdriver into spark plug cap and holding near engine block to see if there is some sort of spark while hitting the electric start... seems a bit dangerous to me. Any advice massively appreciated, cheers. | |
Rogerborg
nimbA
Joined: 26 Oct 2010
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Kickstart
The Oracle
Joined: 04 Feb 2002
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| Posted: 22:17 - 16 Apr 2017 Post subject: | |
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| Hi That is the normal way to do a quick test. Although you can just stuff a plug in it and hold the plug against the engine while you do it. But that won't tell you how healthy it is. The manual will have a range of values for resistance of the coil, and it might work while outside those ranges. Hence you really need a multi meter. Even then things change with temperature. Also some coils have an integrated cdi unit. In which case full tests might not be possible with a meter. All the best Katy | |
RickTaff
Nova Slayer
Joined: 28 Jul 2016
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| Posted: 22:24 - 16 Apr 2017 Post subject: | | ||
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Thanks,. Will get hold of a multi meter and check what Ohms i should be reading | |||
RickTaff
Nova Slayer
Joined: 28 Jul 2016
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| Posted: 22:25 - 16 Apr 2017 Post subject: | | ||
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Do you know of any other symptoms i would experience besides the ones i listed, if it is indeed a bad coil? | |||
WD Forte
World Chat Champion
Joined: 17 Jun 2010
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WD Forte
World Chat Champion
Joined: 17 Jun 2010
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Robby
Dirty Old Man
Joined: 16 May 2002
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RickTaff
Nova Slayer
Joined: 28 Jul 2016
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| Posted: 10:26 - 19 Apr 2017 Post subject: | | ||
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Was a 125cc Lexmoto Street Bit late replying but the coil was fine. Multi meter test showed coil reading 4.4 ohms, when it needed to be between 3 and 5. Other test with one prong in coil and one in spark plug cap showed a reading of close to 13k ohms. Ideal stated as between 10 and 20k Coil fine... gave bike to a mechanic in the end, he did a few tests and noticed that when starting bike, and giving it a few revs the throttle is unresponsive at about 5-6k RPM and thus the RPM's wont climb. The bike will then make a sort of muted stumbling noise (and exhaust has very faint thumping/popping noise) and cut out, then instantly spit out of the exhaust. [but not every single time] Spit sound is reminiscent of somebody cracking a whip Diagnosed it as a compression issue, and valve clearances need doing. He said it wasn't the piston or rings. Thanks anyway | |||
WD Forte
World Chat Champion
Joined: 17 Jun 2010
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 | The last post was made 4 years, 231 days ago. Instead of replying here, would creating a new thread be more useful? |  |
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How to Test a Motorcycle Coil With a Multimeter
Source: https://www.bikechatforums.com/viewtopic.php?t=319404