Triumph Rat Motorcycle Forums banner

T120 Jumpy on the throttle in low gear

31K views 125 replies 38 participants last post by  CafRacer 
#1 ·
I am a newbie, got the license mid august this year, and bought a 2017 T120 with appr 10´km on the meter. I dont have any experience with other bikes than this one (except the CB600 I drove for the license). I notice that the throttle in 1st gear, and partly 2nd gear is extremely jumpy, which makes me a bit uncertain in slow turns... I know I need to adjust my chain-slack, but is this normal? It feels like the throttle-response makes the bike jump even though I am concentrating on slow, calm movements with my right hand..

Sorry if this has been covered in threads before - but I could not find any similar posts.
 
#3 ·
Not sure about the T120, but my '16 TTR, as all the new modern classics, had slop in the throttle due to the connections with the fly by wire setup.
I installed the Ducati Spacers which removed all free play in the throttle movement and now the bike is as close to old school cable respose as ever. Easy $35 fix!

》》》》》》》》》》Wake Up, Be Nice, Kick Ass, Repeat...... MTFU
 
#4 ·
I don't understand all this talk of snatchy/ jerky throttle on new Triumphs, Its something every rider must get control of no matter what make or model motorcycle and this my friends is a learning curve. If you think that is something wrong with the bike, go out on a deserted road and stay in lower gears and learn to be gentle with that twistgrip on and off till you feel you are in control..
 
#105 ·
For what it's worth, I like my 2018 T120 just as it is. While I've done some simple cosmetic mods to it, I'm really in no hurry to change the way it operates. I came from riding a 1981 KZ550, and only really only started riding again after a twenty five year "child-rearing" hiatus - effectively, I'd never really ridden a "modern bike". My early years were spent on motocross and enduro-type bikes at a time in California where you really never needed to be on a paved road for very long - you'd just ride through the strawberry fields and citrus groves to get where you were going.
That said, I've noticed the throttle issue that's mentioned fairly often, but I simply adjusted to it and, as Roasted mentions, practice throttle and clutch control.
Regardless, this forum is tremendously valuable and I sure appreciate everyone's input, feedback and knowledge.
 
#6 ·
My '16 T120 is sligtly snatchy at low speeds in 1st and 2nd, I've replaced the rear sprocket from a 37T to a 39T and that helped very slightly, the chain is adjusted to about 25-30mm slack - which I think helps too...the fuel injection is a little snatchy, but not very much...it does take a bit of getting used to...keep at it, I do think the new water cooled bikes are very nice machines.
 
#11 · (Edited)
Have to agree with those that suggest paying close attention to throttle control. The high torque engine does make a respectful amount of torque just above idle. So if you give it too much throttle then react by too little, thats when I could feel what you describe when I first started to ride mine. Im in my 60's and have owned my fair share of bikes. This one surprised me the first time I started from a dead stop. Slowly let out the clutch, gave it the amount of gas I was used to. Bit ashamed to admit it almost pulled the grips from my hands. With just a little adapting to it's method of power delivery and response, its become silky smooth, don't notice anything but smooth power delivery now.
 
#12 ·
Snatchy throttle

Guess I have to disagree with some of the other experienced motorcyclists on here who feel that it is just a matter of getting use to this particular bike's throttle. In my humble opinion, the T120 (at least the 2017 model) definitely has a snatchy throttle response in 1st and 2nd, period. You shouldn't have to feather the throttle and/or clutch to start out in lower gears smoothly.

None of my (more than 6 over the last 20 years) other fuel injected motorcycles had symptoms even close to this. Carb bikes were always an easy fix, but even those right off the showroom floor didn't have the issues my T120 has. Once it is up and rolling past 3,000 rpm in 2nd it runs okay, and no problem in 3-6 gears, but the engine is running too lean (which is interesting since most of my riding is over 5,000 ft. elevation and engines run richer at higher altitudes). The demo bikes I rode were same-same. Since 95% of my riding is on the open road, it is a nuisance I could live with, but I have a Booster Plug on order.

Chuck
2017 T120
 
#15 ·
Guess I have to disagree with some of the other experienced motorcyclists on here who feel that it is just a matter of getting use to this particular bike's throttle. In my humble opinion, the T120 (at least the 2017 model) definitely has a snatchy throttle response in 1st and 2nd, period. You shouldn't have to feather the throttle and/or clutch to start out in lower gears smoothly.

None of my (more than 6 over the last 20 years) other fuel injected motorcycles had symptoms even close to this. Carb bikes were always an easy fix, but even those right off the showroom floor didn't have the issues my T120 has. Once it is up and rolling past 3,000 rpm in 2nd it runs okay, and no problem in 3-6 gears, but the engine is running too lean (which is interesting since most of my riding is over 5,000 ft. elevation and engines run richer at higher altitudes). The demo bikes I rode were same-same. Since 95% of my riding is on the open road, it is a nuisance I could live with, but I have a Booster Plug on order.

Chuck
2017 T120

Totally agree.

I've had mine a year, 5k miles, ride nearly every day, and the snatchy throttle was a pain in the ass from the very beginning. Horrible in stop-and-go traffic. Only since adding the booster plug, a bigger sprocket, and the pod filters has the bike begun to finally behave like it should. The clutch is still extremely light, but my current mods have helped immensely with the overall handling in low gears.

The shady electronics are no doubt the biggest issue I've had so far with mine.
 
#13 ·
I am in agreement with Chucker. I bought a Bobber last year and the throttle response was the first thing I noticed. I have been riding bikes for forty years so this isn't my first rodeo. In that time I have ridden hundreds of bikes. However all of them had carburettors the Bobber is the first FI bike I have owned. I am used to it now, but quite often I will switch to the rain map around town as the softer response suits me.
 
#14 ·
To bad we are so far apart from each other. Mine is also a 2017, some comparison rides between bikes would be interesting. At 750 feet elevation +/- several hundred feet in my average riding area. Mine does not exhibit any lean burning issues either. Just putting out there as info for me and my bike. No fuel injection, loose chain, problems. Would not say I am slipping the clutch or feathering the throttle differently than any other bike I've owned. Once again not saying that to disagree or start an argument which can start so easily these days. I've owned other bikes with greater HP but when I compared the torque curves with the T-120, none of them had the torque right off idle like this bike has. I took that to be what I had to adapt to at first. Other than it not being made off the floor to be a long distance cruiser. It's been the best overall bike I've ever owned. Just wishing that same experience for everyone. Or..... I've just owned crap for bikes.
 
#16 ·
Thightening the chain made the bike behave totally different!

Thanks for a lot of interesting answers to my post. I took my bike out today, placed it on the center stand and measured the chain slack to be 4cm (!) Carefully looking at Stuart F´s Youtube video, I adjusted the chain to give a max 22mm slack.

This totally changed the bikes behavior, and the stupid jumpy on/off feeling was gone! Fantastic! :laugh2:

Ok, so the throttle reponse is still a bit jerky in 1st gear, but now the bike feels much more tight and maneuverable.

I am a new driver, this is my first bike, and it was big fun too experience I could fix this so easy my self. I dont have any clue if it is normal that a chain can slack out this much in only 14 months (bike was new July 2017).
 
#17 ·
Glad to hear of your progress Vedal. Was wondering what your take was on all the variables you received for replies. I have never seen that amount of difference in judgment for a single bike. Perfect as is (me), others felt bike is almost unusable until sprockets, programming, or other parts removed/ replaced. Some feel it's unsatisfactory below 3000 rpm with serious electronics problems. Glad your closer to your happy place. Guess thats what all of us are looking for.
 
#18 ·
Thank you, Bikertucker.
Well, I guess different bikes have their own personality, and that´s exactly why I bought the T120 - it has that amazing personality! Those who designed the bike had their time of thinking, designing the thing, and I know am not in any way competent to believe I can make anything better. The ride I had today, after adjusting the chain, made me happy. But I understand those who wants to improve bits and details. I am not the kind that want to change every bits an pieces to improve the bike. If I am not satisfied with what I bought, I would change the whole ting into another brand or make. But we are all different. I dont care about the "tool" - I care about the experience :) and I found the T120 is a great machine!
 
#20 ·
I believe we've finally found the reason for the 'snatchy' throttle. The Triumph ECU has been created with only 23 steps in the map from the throttle grip, so when feathering the throttle you're jumping by 4% up and down with each tiny movement of the throttle, probably contributing significantly to the on/off effect.
The BoosterPlug 'resolves' this by making the engine far too rich. This 'smooths out' the throttle because it essentially bogs the engine down. I wouldn't want this, but I can see why people might prefer it.
We're looking at an alternative approach that also introduces a 52 step throttle as part of the process, and it will be very interesting to see if this helps the twitchiness issue. If it does I'll let you know.
 
#22 ·
I believe we've finally found the reason for the 'snatchy' throttle. The Triumph ECU has been created with only 23 steps in the map from the throttle grip, so when feathering the throttle you're jumping by 4% up and down with each tiny movement of the throttle, probably contributing significantly to the on/off effect.
Are all ride by wire throttle systems this primitive? 23 steps seems rather limited for a modern potentiometer.
 
#21 · (Edited)
Thanks jsobell! That neatly explains the jerky throttle phenomenon.

I've found that starting out on a ride with a cold motor in rain mode also seems to damp out that characteristic jerky T120 throttle response. I'll often forget to change the mode to road, but that happens anyway on any subsequent start. That jerkiness is not as apparent after the subsequent starts, so the bike just gets left in road mode. Decatting seems to have helped, too.
 
#23 ·
It's not the potentiometer that has 23 levels, it's the map in the ECU that looks at the resistance reading and from that chooses the 'row' to use from a lookup table in the map. The ECU uses a lookup map of values to implement the three 'modes', which outputs a row to lookup in the mixture map, which is correlated against the rpm then adjusted based on the MAP sensors and air temp (and O2 sensors if you have those fitted) to come up with a value for injector pulse timings and ignition timings. It's a relatively straightforward process, but a juggling game, and these bikes don't have a huge number of sensors.
They simply decided that the initial maps would only have a limited number of values to look up from. Perhaps they made it too low resolution for an engine with lots of low-down torque, making it twitchy because you're often right on the edge of two values.
We'll hopefully find out sometime soon.
 
  • Like
Reactions: PÃ¥l Vedal
#25 ·
Honestly, just get a booster plug. People can say "Gotta get used to it" or "learn your bike", but the reality is the throttle response is ridiculous in low gears. I've ridden dozens of bikes, from japanese classics to modern sport bikes to big twin cruisers, even liter bikes are nowhere near as bad as these ones. Maybe if you only ever ride on nice provincial roads with no traffic and can stay in 3rd gear or higher all the time its not a problem, but anywhere that has decent traffic its just painful. You basically get ripped off the bike trying to go from closed to open throttle in second gear below 3k RPM without riding the clutch. The booster plug really does sort it out by bogging down the engine with extra fuel at low RPM and small amounts of throttle.

The real way to fix it would be a power commander, but for the price, unless youre going to do other performance modifications and need that full tuning power, I dont think its worth it. The power commander is obviously "better", but the booster plug is "good enough" and you dont have to tear apart the entire bike to install it either.
 
#26 ·
"Ripped off the bike?" It's like we don't own the same model. I just put mine in rain mode until it warms up and everything's very smooth. Most of the time I don't even bother to do that.

Installing a booster plug will kill the T120's fuel economy. Mine's a consistent 60-65 MPG, the best I've ever had of any bike owned. Not gonna mess with that.
 
#27 ·
So if, in 2nd gear, you engine brake and then open the throttle it doesnt immediately take off on you? Mine will instantly accelerate like 10mph just transitioning from closed to open throttle and will accelerate all the way up to around 40mph without changing the throttle position at all. And it does this in under a few seconds, at the very smallest possible throttle opening. The only way I can even keep any kind of steady speed sub-25mph is to bog the engine by riding in 3rd at very low rpm (like, 1000-1500rpm, on the verge of stalling). Other than that I need to constantly be riding the clutch as it will only accelerate in 2nd gear, it will not maintain any speed whatsoever, even with the throttle at the absolute smallest opening possible, which heaven forbid you hit a bump and accidentally push the throttle forward 0.1mm to closed, because as soon as you open the throttle again the bikes going to lurch forward like an alcohol funny car off the line.

And yes sadly, I need to keep it at or under 25mph because traffic wont allow any faster during my commute. All fuel injected bikes are twitchy on the transition from closed to open throttle, but honestly this is the absolute worst one I'd ever dealt with and I've owned 8 now. All chain driven, 4 of them ride by wire, this one was uniquely awful. I'd even be willing to concede that some bikes have a factory flaw in the mapping or one of the sensors, because again I've ridden liter bikes in the same traffic and had no problems keeping them under control without constantly having to work the clutch to keep them from accelerating out of control.

I didnt notice any change in fuel economy. The ECU thinks its colder by 20 degrees, so you'd use as much fuel as you would on a 5 degree day compared to a 25 degree day. Negligible amounts, but enough to level out the engine. And this is only at small throttle openings and during acceleration, not all the time. I'm happy with it.

And no, the different riding modes did not help sadly. It was ridiculous in all three.
 
#29 · (Edited)
I've always wished some one could do a side by side comparison of bikes. I am in the camp of nothing wrong. I would love to ride the bike of those who experience out of control power and surging while keeping the throttle position steady. Maybe I did adapt quickly and modulate the throttle unlike any other bike I've owned to obtain smooth throttle response. Equally would love to invite someone who experiences all of the reported faults, to ride my 2017, T-120. Us both together, on each others bike, riding in the conditions where they experience all the problems. On my bike are they now experiencing smooth throttle response with no surprises. While I am experiencing herky jerky uncontrollable throttle response on their T-120. This would indicate Triumph does indeed have a severe manufacturing problem that does need addressed. But if my bike which I call silky smooth, is now herky jerky with out of control throttle response ridden by someone else. While I experience silky smooth throttle response while riding their problem bike. Of course this indicates different issues. As I've stated previously, never in my life, have I in 47 years of riding seen such a Grand Canyon gap in opinion in performance of the same model bike. As I read this thread and others, to me it reads as if I am reading about two entirely different models made by two entirely different manufactures. Maybe Triumph to distance themselves from any responsibility should simply rename this newest model of T-120 to, The "PITBULL" .
 
#30 ·
I bought mine used so sadly I have no warranty or dealer service available (its also a 2016), and the closest dealer is 2 hours away. I bought a boosterplug rather than spend 400 dollars at the dealer for them to tell me "Nothing wrong with it" like everyone else whos tried to have triumph take a look at it. Trust me, I spent dozens and dozens of hours looking into this before deciding to drop 150 bucks on a "useless" box of resistors, and I dont regret that purchase for my bike.

As far as comparison without being able to do an actual side by side, just do what I described. Get into second gear and have the throttle opened the smallest possible amount (just past the dead zone where you start to feel resistance in the throttle). Does yours accelerate all the way up 40-45mph in 2 seconds like you've got the throttle way more open, or does it maintain a steady speed? Does it make any difference if youre at 1% throttle opening or 30% in second gear? If theres no difference then we have the same "issue", and I just dont know how to ride. But like you, I have 30 years on bikes and I really doubt I just forgot how to ride in the 6 hours between parking my old bike and picking this new one up :)
 
#31 ·
I bought mine used so sadly I have no warranty or dealer service available (its also a 2016), and the closest dealer is 2 hours away. I bought a boosterplug rather than spend 400 dollars at the dealer for them to tell me "Nothing wrong with it" like everyone else whos tried to have triumph take a look at it. Trust me, I spent dozens and dozens of hours looking into this before deciding to drop 150 bucks on a "useless" box of resistors, and I dont regret that purchase for my bike.

As far as comparison without being able to do an actual side by side, just do what I described. Get into second gear and have the throttle opened the smallest possible amount (just past the dead zone where you start to feel resistance in the throttle). Does yours accelerate all the way up 40-45mph in 2 seconds like you've got the throttle way more open, or does it maintain a steady speed? Does it make any difference if youre at 1% throttle opening or 30% in second gear? If theres no difference then we have the same "issue", and I just dont know how to ride. But like you, I have 30 years on bikes and I really doubt I just forgot how to ride in the 6 hours between parking my old bike and picking this new one up <img src="http://www.triumphrat.net/images/smilies/smile.gif" border="0" alt="" title="Smile" class="inlineimg" />
Yes, there is an issue with jerkiness which jsobell explained and others have experienced. Out of control acceleration? Uh uh. It’s not fair to discount your experience without riding your bike. Sounds like it’s just effed up.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top