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Early symptoms of HT Coil failure ??-----

Posted: Sat Jun 07, 2014 10:42 pm
by Alan R
Hi guys----------Can't remember which way round is it for the early signs of an HT coil starting to fail........Mis-firing from the higher RPM downwards----OR the other way around ??

Early symptoms of HT Coil failure ??-----

Posted: Sat Jun 07, 2014 11:52 pm
by Leon Novello
Hi Alan: Not much help I suppose, but I had problems with a Honda once that it wouldn`t idle properly. I found that the previous owner had fitted a car coil, or maybe it was faulty. I bought a genuine Honda coil and it idled like a Swiss watch after that.

Early symptoms of HT Coil failure ??-----

Posted: Sun Jun 08, 2014 11:48 am
by Gwilly
Trouble is Alan there can be different symptom types with dying coils..

Best is when they just short out and fall flat on their face, refusing to provide any spark for starting..

Another will start and tick over fine but will give weak or intermittent spark as a handful of throttle is applied pulling away or on long uphill gradients..

Often symptoms appear as the coil gets hot on a fast run.. A failing plug or HT cap with high resistance can make the coil work harder creating more heat..

Fortunately with a single it is fairly cheap and easy to substitute each component until the fault is cleared, especially if ohms resistance testing is giving "negative" results..

Just be thankful your not running a six cylinder CBX or the newfangled digital electronics that cannot be changed for a few quid to test results...

Hope the showery weather didn't spoil your Axminster trip to much.. ATB Gwilly..


Early symptoms of HT Coil failure ??-----

Posted: Mon Jun 09, 2014 9:38 am
by ed.lazda
When the coil went on my Bullet, it just died suddenly, no warning, near home at the end of a long weekend away. And I agree with Gwilly. Took me half an hour with a multimeter to diagnose it, then another half hour and all of about twenty quid to put it right.

Early symptoms of HT Coil failure ??-----

Posted: Mon Jun 09, 2014 11:21 am
by Adrian1
Don't mean be a smart**** but are you 100% sure the plugs is good?

Early symptoms of HT Coil failure ??-----

Posted: Tue Jun 10, 2014 10:51 pm
by Paul M H
Yes agree with ed.lazda same problem today see my earlier post. The coil just suddenly died no spluttering or miss fire it just blow like a light bulb or someone had cut the ignition or hit the kill switch.

Early symptoms of HT Coil failure ??-----

Posted: Wed Jun 11, 2014 2:53 pm
by Alan R
Hi guys------- ADRIAN, yes the first thing I did was to change the plugs for known OK ones....no joy I'm afraid...........LEON, these are new ( 1 year ago ) pattern coils from WEMOTO for the HONDA GL1000 BUT, I suspect they may be 10v as the bike originally had a Ballast Resistor for cold starting......This has been removed so I now have a "Standard" 12v set-up....When I asked the suppliers I was assured that they were for 12v use.........GWILLY, had a great time just south of Axminster based at MUSBURY....one day "scorchio" on Weymouth beach followed by another "scorchio" at Lyme Regis beach...Other days blustery and light showers but nothing to upset the week....Other symptoms now lead me to think it might be the mechanical auto-advance unit playing up ( weak or broken spring ??)............................ I'm currently laid-up with a bad case of Montezuma's Revenge !! so can't stand still at the bike for more than 5 mins at a time !!------------

Early symptoms of HT Coil failure ??-----

Posted: Wed Jun 11, 2014 8:31 pm
by JTL
Hi all... I have a coil that turns very warm/hot when riding for more than 20 mins (slow and fast). I can touch it with my bare hands, buts it's hot. It's the OEM "Lucas" on a 500 cc 2003 Indian home market Bullet. It has done 21K km. Is this the first sign of a failling coil?... Jacob

Early symptoms of HT Coil failure ??-----

Posted: Wed Jun 11, 2014 10:33 pm
by Leon Novello
They all get hot, Jacob. Anything with 40000 volts running around inside will get hot.

Early symptoms of HT Coil failure ??-----

Posted: Thu Jun 12, 2014 4:05 pm
by JTL
Good news, Leon. Thanks... Jacob