New T120 Surging

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Siddigger

Member
Picked up a new T120. Run great till I took it in for the 500 mile checkup. The bike now surges. Real pain in lower gears. Going around corners in 1st or 2nd gear the bike bucks. Could dump the bike if gravel or wet. Can not hold a steady speed without surging. Took it back to dealer and they said it run fine. They stated all they do is change oil and do a readout which passed. Is it true that is all they do? Thanks
 
i also picked up a T120 Black a little over a month ago. no surging or stalling that I have experienced. bike runs great and picks up well but it could use a few more horses. it's also too quiet. waiting on V&H to release their exhaust soon. also, be on the lookout for a fender eliminator kit from New Rage Cycles. Should be out in a couple of weeks. I saw their prototype and it's nice.
 
Picked up a new T120. Run great till I took it in for the 500 mile checkup. The bike now surges. Real pain in lower gears. Going around corners in 1st or 2nd gear the bike bucks. Could dump the bike if gravel or wet. Can not hold a steady speed without surging. Took it back to dealer and they said it run fine. They stated all they do is change oil and do a readout which passed. Is it true that is all they do? Thanks
Digger,
There is a newer version ECU tune/map available for the T120 already which may solve your problem.
Your dealer should be able check your version and if required to download the latest ECU tune.
But what you may try first is to reset the ECU adaptation yourself.
Procedure is to start your T120 from cold, don' t touch or switch anything and let it idle until the cooling fan starts. Let it idle for another 12 minutes, again without any switching. When done switch the engine off.
The adaptation will be reset when re-started and usually clears the off idle stumble.
This procedure works not only for the T120 but also for most other KEIHIN equipped Triumphs.
Even for the aircooled T100 EFI but they need 20 minutes from cold (no cooling fan).
 
Picked up a new T120. Run great till I took it in for the 500 mile checkup. The bike now surges. Real pain in lower gears. Going around corners in 1st or 2nd gear the bike bucks. Could dump the bike if gravel or wet. Can not hold a steady speed without surging. Took it back to dealer and they said it run fine. They stated all they do is change oil and do a readout which passed. Is it true that is all they do? Thanks
Hello my 2017 T120 had the same problem take your throttle apart and spray some contact cleaner on it and dry it with mild air pressure
 
Digger,
There is a newer version ECU tune/map available for the T120 already which may solve your problem.
Your dealer should be able check your version and if required to download the latest ECU tune.
But what you may try first is to reset the ECU adaptation yourself.
Procedure is to start your T120 from cold, don' t touch or switch anything and let it idle until the cooling fan starts. Let it idle for another 12 minutes, again without any switching. When done switch the engine off.
The adaptation will be reset when re-started and usually clears the off idle stumble.
This procedure works not only for the T120 but also for most other KEIHIN equipped Triumphs.
Even for the aircooled T100 EFI but they need 20 minutes from cold (no cooling fan).

I had this same problem and thought I would be buying a new ECU but gave this a try and amazingly it worked great. No more surging!
 
Picked up a new T120. Run great till I took it in for the 500 mile checkup. The bike now surges. Real pain in lower gears. Going around corners in 1st or 2nd gear the bike bucks. Could dump the bike if gravel or wet. Can not hold a steady speed without surging. Took it back to dealer and they said it run fine. They stated all they do is change oil and do a readout which passed. Is it true that is all they do? Thanks
take your throttle apart and clean with contact cleaner dry with mild air pressure
 
This is why I have avoided buying a British bike. As much as I love Triumph (since 1956) the reliability just isn't there after living with Honda for many years.
 
Picked up a new T120. Run great till I took it in for the 500 mile checkup. The bike now surges. Real pain in lower gears. Going around corners in 1st or 2nd gear the bike bucks. Could dump the bike if gravel or wet. Can not hold a steady speed without surging. Took it back to dealer and they said it run fine. They stated all they do is change oil and do a readout which passed. Is it true that is all they do? Thanks
Just took my new Bonnie (2018) in for the first 500 mile service. I did not notice anything weird afterwards, but I have only ridden it home ~30 miles.
 
Gheeze...hope all this talk of the T120 having ECU issues and unable to correct is ---well just talk.
Having just purchased a 2018 T120---rode it 225 miles home---didn't notice any problems and it had 575 miles on it when I got it. Now over 800 miles. Is there any place all these problems are noted,,,or just on the forum here?
I would think all this would be compiled and noted at one site.
Maybe I should have gotten an older twin with carburators---and spent several grand on the engine hop ups--probably getting at least 100 HP out of it...and no F.I. and computers to worry about.
 
JoDArk, the original poster was writing in 2016, so it must have been a 2015/2016 T120. I can't imagine Triumph (or any other reputable manufacturer) allowing such a trouble to continue in the product for 2 or 3 years, so your 2018 T120 should be free of this problem. However, if something troubles you about your T120, DO NOT delay getting it back to your nearest shop.
 
JoDArk, the original poster was writing in 2016, so it must have been a 2015/2016 T120. I can't imagine Triumph (or any other reputable manufacturer) allowing such a trouble to continue in the product for 2 or 3 years, so your 2018 T120 should be free of this problem. However, if something troubles you about your T120, DO NOT delay getting it back to your nearest shop.

Thanks---hopefully no problems. I'll know next week when I take it for a weekend trip--maybe 1500 miles or so.
There will be a Triumph dealer where I'm headed if any issues pop up. Those first 225 miles I put on were all on Interstate at 70--75 and she rode great...except I couldn't hear the exhaust note with the wind and my helmet on---that has to be fixed---so far what I've seen and heard on YTube is the Remus slip ons….but $$$$$$
 

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