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Ping slap cough, on quick throttle blip under load

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13K views 42 replies 15 participants last post by  joosuk96  
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#1 ·
This may be normal but I am concerned with a certain reproducible behavior on my 17 ST.

At a standstill, engine idle, letting out the clutch slightly, and quickly cracking the throttle open - sometimes results in a brief metallic sounding "cough" before engine RPM increases as expected.

The sound coincides with a hesitation in power output, and a perceptible but very subdued knock sensation felt in the engine and chassis.

I fear it is piston slap, detonation or some other undesirable condition. It does not happen in neutral, at least not that I can tell. I don't tend to rev the engine for no good reason while not in gear.

If I crack the throttle open more gradually at first, and then quickly mash on it, slipping the clutch, there is no cough, and I can accelerate hard. The condition is strictly limited to going from idle to wide open, near instantly. Which I do not do frequently, but occasionally find the need to open her up like this under specific circumstances. And the cough sound is troubling as both a mechanical concern and failure to deliver power at the moment I desire.

I've been told that this is a fueling issue, where the throttle body is unable to supply the required fuel for a very sudden request for more fuel, when coming off idle. Seems plausible, but does anyone else have an explanation?
 
#2 ·
How many miles on your bike? I know some Thruxton 1200s experience periodic stalling when blipping the throttle or after prolonged idle and leaving a stop and grabbing a hand full of throttle. Mine did this and still does on a rare occasion emit a loud click and the engine shuts down. Starts right back up. The issue was improved slightly for the 1200s with the new tune Triumph release shortly after the 16s entered service. Also, the more you ride the bike the more the ECU learns so issues should subside. Another thing you might try is the idle relearn procedure. From dead cold, start the bike (no throttle input). Let the bike idle until the fans come on (~20 min) and then another 12 min after the fans come on. Shut the bike down and restart. This should help the idle situation and the clicking noise. These bikes are fuel injected with throttle by wire. I have heard the clicking noise are the throttle body steppers. Ask the dealer if there is an updated map for your bike and the check the throttle body balance. Your bike being a 17, doubtful there is a new tune available. The other alternative is to run a Power Commander V with improved fuel mapping which I have heard takes care of these issues. Good luck with it.
 
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#3 ·
It's pre-detonation, and it's been discussed dozens of times on here, so just search for one of the dozens of "my bike stalls" posts.
It's not fuelling, as that results in a splutter and stall, and official word over here from Triumph Australia is that they don't do it for more than the first 5000 miles, and they believe it's due to poor valve bedding from the factory, hence why it resolves eventually as the valves bed into the seats better. Fact or fiction? Who knows, but it doesn't look to be related to the ECU.
 
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#7 ·
Thanks for this info, I will look for those other threads.

My engine never stalls, it is just a "misfire" or similar. The sound is a bit like a tiny hammer lightly striking the side of the engine.

The fact that I can control the condition with the throttle should mean something. Slow (normal) throttle opening from 0% to 10% and then cracking it wide open a moment later equals no problem. It is only when quickly going from 0% to 50% or more, and asking the engine to come off-idle to rev up as fast as it will allow. The cough happens right at the moment it goes off-idle, but then otherwise the RPMs climb rapidly as you'd expect.
 
#4 ·
@Delta i have also been experiencing the metallic ping you described on my 2016 ST on sudden throttle input.
it's reproduce able in neutral as well.

the ping was very rare initially but with 10000 Kms on the ODO it became frequent.
As i felt that the ping has something to do with the piston or cam chain, the bike is currently at the service centre.

the Service Centre peps have recorded the ping and sent it to Triumph India and are awaiting further instructions.
 
#8 ·
Gotta ask about fuel grade? I was running 87 pure gasoline and switched to 91 pure. It made a noticeable difference in off idle sound, and performance. I don't wear a helmet, so I'm very conscious of engine sounds. I'm not yet educated on the new Triumph engine computer control. I'm wondering if they use a Piezo, or what, for knock detection on these. IME, a water cooled engine "should" be less prone to detonation, but a lot of it comes down to the combustion chamber and how well they clean the piece, as well as the water flow route through the head itself? A 10.50 compression engine, IME, begs for the highest octane you can give it.
 
#12 ·
I have it happening also. Just as described. Always under no to light loads and always cracking the throttle off idle. Never had it stall as a result though.

Here's what I find odd and why I believe it is the fueling and/or ignition map.

I had similar experiences with a 1980s UJM. A Suzuki GS850g, a bike built during a time notorious for lean tuning for emissions purposes...
 
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#14 ·
rebel1735 said:
recording of the Ping sound http://vocaroo.com/i/s1PwVig4ltzM

any insights?
Click to expand...
on second thought that is rather odd if that's what your talking about and your just bliping the throttle.that sounds like a knock to me , i know the manual says 87 octane . but for any engine exposed to full throttle acceleration, routinely i go with 89 minimum and full premium 92 or 93 , hey guys see if it makes a difference >
 
#17 ·
Sounds like pre-detonation. Try a tank of Premium and see if it does it any less.
Honestly, with 11:1 compression and relaxed timing you shouldn't get any knocking, but if the fuel has no inhibitors then it's possible. I can get this to happen if I have my timing increased by 5% and I use low-octane fuel (I've tried it) so I now stick with premium.
 
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#18 ·
First tank of premium 93 octane went in this morning. Previously using regular 87 octane, ran down to one bar on the fuel indicator, not much left.

Engine did seem to respond differently almost immediately, a touch quicker to spin up RPMs, slightly louder, and most importantly, I am not able to reproduce the ping. At least not yet, I'll have to do some more testing.

Just to clarify, since the thread title is a little inaccurate, the ping noise happens under NO load. It only happens when revving quickly, coming off-idle. I'm fairly certain it is engine knocking:

https://en.wikipedia.org/wiki/Engine_knocking

Thankfully it only occurs off-idle, and only on rare occasion. Under load, the engine runs as expected.
 
#22 ·
finally managed to have a world with tech. rep. from Triumph India, his explanation was that the sudden throttle input interferes with the engine cycle before it completes and therefore the ping. He also said that the same would be present on any big capacity high torque engine.

As the ping is more easy to replicate on my motorcycle on hotter days, my hunch is that its a fuelling issue which can be resolved by using something like power commander etc. for the next one year while the motorcycle is under warranty i have decide to practise a smooth throttle action.

@Delta are you still sticking with the 93 octane fuel? i am little confused since 93 octane is not is the fuel recommend by Triumph for these engines.
 
#25 ·
I run on 87 octane like the owner's recommends with an extra tea-spoon of Arnold Palmer when I re-fuel. The Lite, not the Zero. Hasn't done the throttle-blip 'ping' thing since.
Image

(Oh, and I did that Owner's Handbook 'Do-It-Yourself', start the engine when cold & don't touch the throttle, while letting the engine idle for 12 minutes from the first time you hear the cooling fan turn on. Hasn't 'pinged' since... Not stating that this is, or is not the remedy. But hasn't happened since I did that. And it was nasty in the mid 90's(F) the last two times I rode.)
 
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#30 ·
Wish I would've seen this before I made my own post. Newbie mistake, do I need my flame suit? Haha.

OP, thank you so much for posting a sound clip of it. I have the exact same sound on my Street Cup. I just recently switched from 93 to 87 and the timing of the sound correlates with the gas switch. Now I have an excuse to take a ride tonight to burn off the 87 and fill up with 93.

How immediate did the sound go away for you guys after running 93? Has anyone experimented with running mid-grade to save a few bucks?
 
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#31 ·
No flame suit required. This site could use a FAQ or some stickies, though.

It was @rebel1735 that posted the video, where the knock was very pronounced and repeatable. Mine's never been anywhere near that bad.

I have not tried 91 octane since saving ten cents per gallon over 93 octane doesn't net much on such a small gas tank.

Not sure how many miles you log in a given timespan, but saving fifty cents per tank is hopefully a non factor for people riding near new, ten thousand dollar motorcycles. :0:)
 
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#32 ·
I've experienced these same issues intermittently since purchasing my bike and I have run 91 or higher since new. I get the occasional ping, I've had the sputter cough, I've had a detonation/backfire incident, and I've even had the bike stall on a throttle blip shortly after startup. All incidents are always on throttle blip, most of the times at idle but I have had it happen to me when going to downshift. I have the off road exhaust coming in shortly so my hope is that with a more rich remap and a little less back pressure maybe the issue wont arise? (not the reason I got the exhaust but maybe it will help?) It doesn't happen very often but when it does its kind of frustrating.
 
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#34 ·
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#35 ·
That thread is about the 1200HP engine common to the Thruxton owners and covers a "clicking" and stalling issue that was cured with the updated stock tune from Triumph back in July of 2016. The most helpful post in that thread was unsurprisingly from Forchetto, here:

http://www.triumphrat.net/water-coo...ater-cooled-twins-technical-talk/704314-thruxton-r-idle-issues.html#post8361146

Possibly these two as well:

http://www.triumphrat.net/water-coo...er-cooled-twins-technical-talk/704314-thruxton-r-idle-issues-2.html#post8704825
http://www.triumphrat.net/water-coo...er-cooled-twins-technical-talk/704314-thruxton-r-idle-issues-2.html#post8903474

This thread one is about engine knocking on the 900HT engines, regardless of the tune. There is not a stalling issue here.

I question your assertion that the two threads are discussing one and the same issue, since the updated stock tune does nothing for the problem being discussed here. That and the fact that we are discussing two different engines. And that a simple octane bump has a direct effect on curing the knock.
 
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#42 · (Edited)
I think it's more of a problem with our crappy 10% Ethanol gas than an octane problem. I only use Non-Ethanol 91 octane in my 2024 T100 with no problems. It is the only octane of Non Ethanol gas available where I live otherwise I would stick with regular Non-Ethanol 87 octane if I could get it. I also use it in my 1981 Honda CB750C, not for the higher octane but because I believe the 10% Ethanol gas is horrible for fuel injectors in EFI bikes and even worse for carbureted older bikes. When Ethanol in gas burns it creates water. This water usually burns along with the gas but over time can create residue that can plug up injectors or carb jets. Try switching to Non-Ethanol gas and running a couple tanks of gas mixed with a couple ounces of Marvel Mystery Oil or Sea Foam. It will clean your fuel system and you'll then know if was dirty fuel system or not. If you don't have Non Ethanol gas available to you I would add 2 ounces of MMO to every tankful of gas all the time to keep the fuel system clean and get some top end lubrication as a bonus. Just my 2cents. Cheers!
 
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#43 ·
Surprisingly, it was solved. After going to Triumph and requesting an ECU update, I tried using regular octane fuel and the pinging symptom disappeared. Triumph said that the crankshaft may have been misaligned and then adjusted, but this does not seem to make sense, and it seems that the existing ECU mapping setting was strange. Since this issue does not exist in recent model years, it seems that it was a problem with the ECU version.
 
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