Hi everyone. My problem conserns about possible ignition coil failure in my Thunderbird Sport. I bought this bike end of last winter. Bike is year 2000 model and driven 46900km. For that age, it is in good condition. Only bad was that i didnt got the servicebook with it. So.. I did oil change month ago. Also did all basic checkings and add some radiatorfluid. Bike starts nice and runs good, But... After it gets warm, i can feel something is not in balance. It starts to run bit rough, gives some ”puffs” like missing fuel or spark. Idle is not good and wants to go off. When driving and rpms are over 2000-2500 it runs ok and accelerates very nice, but whe stopping on trafficlights it needs some help with throttle to stay running. I changed the new correct sparkplugs (NGK) and for 300km it was like new bike. Idle was nice and it was running very nice in every rpms. After 300km it started to do same tricks again and idling went bad again. Im newbie with bikes, but i have done lots of reserch and i found these symptoms could cause from several problems, but the most possible thing here could be the bad ignition coils. I have fixed cars and mopeds so i know something, but not from the soul of motorcycles. Today i took my crappy cheap multimeter and did some research with ignition coils. First. Battery is ok. Voltage without running is 12,94V and when running 14,66V. I saw this bike has original Gill ignition coils that has never been changed. I put my multimeter to 200 ohms and mesured all three coils. Primary gives me 0,5 ohms with every coils. Then i put my multimeter to 200K and also 20K and checked the secondary from coil without sparkplugwire and it gives me nothing.. Nothing at all.. what went wrong? I did everything correctly. Same with every coil. Shouldnt this bike be dead? It still runs.. even little bad when warm, but still it runs. I checked sparkwires separately also. I put multimeter to 20K ohms and every cable gives about 5.30- 5,39.. can you tell me what does this all mean? Did i do something wrong or is it like im thinking now.. ignition coils are in bad condition and needs to be replaced? Here is also little video from my TBS running on idle when warm. Thank you for your help
Welcome Sami, The secondary resistance should be about 21.5 to 22.5 K ohms so you’ll need to change your meter to a higher range to get a reading, 200K range perhaps. The leads should be a low resistance and all similar, remember to take into account the resistance of your meter leads too.
Hi freck Thank you from your answer. Yup. Sorry i didnt write correctly. I mean i checked the secondary resistance with both 20K and 200K ohms.. and nothing.. i ll make correction in my first message.
Have a look here, some info on checking coil resistances. https://www.triumphrat.net/t3-sport-touring-forum/175886-coil-secondary-winding-test.html
If the bike’s still running then your coils must be ok, though if it doesn’t run as well when warm then there could be something breaking down with heat. From the resistances you’re measuring on the leads these could be your problem. Is what you’ve measured in ohms or K ohms? Does it include plug caps? Have you checked for corrosion at all the connections?
I own 2 of these T-3 powered bikes. Coils are a known problem with them. I have had to do both of mine. The factory supplied "Gill" coils. When they get old they start breaking down. When this happens I just get rid of all three of them, because they will just die, one at a time. I have long suspected that them being mounted between the engine and the fuel tank does not help the situation. Gets pretty hot in there. ...J.D.
You would think if being a known problem the makers would think about changing the coil make...coils will happily take quite a bit of heat if made correctly most petrol cars use coil on plug and they get far hotter during use than any remote bike coil.
Sami my guess is you are taking the measurement at the wrong points on the coil? As you say the bike runs so the coils are working but possibly not very good. I am at work and can't remember where to take measurements but youtube should help.
Triumph seemed to have solved this problem. I had it on my 1995, and my 2000 Triumph, but the 2002 has so far not shown any signs of this problem. I know.of some owners who have converted thier earlier Triumph T-3's to a coil on plug setup. I just went with a different brand of coil. That seemed to solve the issue. ...J.D.
Hi and thanks everyone for advices Im quite sure, i did multimeter messurements correctly, but i try once more. I did some research and found lot's of talk about ignition coils with these symptoms. They are quite the same as in this link below. Like i said before, the bike has the original GILL -ignition coils and those are 19 years old. Bike has 46900km, and that is not so much, but we have hard weathers here in finland. of course nobody drives wintertime, but not sure how this bike has been stored. When i bought this at winter, it was stored in small shed with same temperature than outside (winter -8 to -25 celcius) so of course with time, this kind of temperature changes are not good. Also as you can see on video, RPM:s are not shown correctly on tachometer. Tachometer works, but show too low RPMs. https://www.webbikeworld.com/motorcycle-ignition-coils/
Multimeter on 200k ohms. Red wire on primary + terminal and black wire on HT terminal .. Nothing! Same when turn multimeter 20k ohms. Or even red wire on - terminal. Can this be right.. ? Im starting to feel stupid and confused. Like i told before, i do know some mechanics, but electricity is not my strongest part. Still, bike starts and first runs ok, but after warming idle goes bad.
I also have a thunderbird sport. I also had the same issues when I first bought it 2 years ago. Riding it regularly seems to have solved the issue. It still idles a bit funny at times, it gets hot, the tachometer reads wrong at times, it's heavy ....... but it's an awesome bike, wouldn't change it for the world. Just go and ride it!
Here is video after 10mins running. Engine wants to stall. Sounds like misfiring with "puff puff" sounds from the right exhaustpipe. When giving some gas, it still responce nicely and takes RPM:s, but idle is bad.
This problem doesn't bother me when riding on highways and roads where you can just go. But when arriving town with trafficlights and lots of stops, this takes enjoyability away. On every stop you need to keep engine running instead just ride and enjoy. Annoying symptom
I have a '98. I haven't changed them, I believe that they're the originals, but like yourself I looked into them as a potential reason for certain quirks. Last summer I rode 2400miles across Europe, in 11 days, it ran better than ever getting that use!
