Facebook slapped me in the face with this this morning:
Saturday, 10 May 2025
Triumph 955i Stalling Issues.... Fixed!?!
Sunday, 30 May 2021
That Darned Tiger: Stalling issues on a Triumph Tiger 955i
The Tiger worked for a couple of months this spring but started recently stalling again. The engine was getting rougher and any time I came off throttle quickly, such as downshifting, the engine would 'fall' right through where it normally idled and stall. If I didn't downshift and let it drop to idle on the clutch it wouldn't stall.
If you're familiar with the blog then you know this isn't my first dance with Triumph's early fuel injection systems. I've replaced the vacuum housing for the idle control system (a plastic piece that looks a bit under-engineered) and all the hoses and gaskets last year when chasing this thing, but looking over the deep winter maintenance I did I don't think I rebalanced the fuel injection after taking it all apart to clean it.
Balancing the FI on these 955i Triumphs is tricky because you have to take apart a lot of the bike just to get at the adjusters. I've been in and out of this so many times that I'm quick - I don't even have to keep the fasteners sorted because I know where they all go.
To balance the fuel injection on a 955i Triumph engine, take the fuel tank and airbox off. On the Tiger, if I put the fuel tank next to the bike the fuel lines are just long enough to connect so I can run the engine with the tank attached but off the bike.
NOTES & RESEARCH
http://tkmotorcyclediaries.blogspot.com/2020/07/triumph-955i-engine-stalling-next-steps.html
http://tkmotorcyclediaries.blogspot.com/2020/07/triumph-955i-stalling-issues-part-3.html
http://tkmotorcyclediaries.blogspot.com/2021/01/triumph-tiger-955i-old-rubbers.html
https://www.triumphrat.net/threads/955i-engine-stalls-need-help.16567/
Throttle balance?
https://www.thetriumphforum.com/threads/955i-stalls-and-wont-start-until-cold.27123/
https://www.thespeedtriple.com/threads/my04-speed-triple-stalls-the-engine.26192/
https://www.reddit.com/r/Triumph/comments/b45o3s/rough_idle_and_stall_out_problems/
Throttle balance (again) - do it with TUNEBOY this time!
Check rubber parts for perishing:
https://www.triumphrat.net/threads/stalling-and-fuel-adaption-problems.973460/
Tuesday, 16 March 2021
Tiger Triage
Out in the garage I flipped on the tunes, got the Tiger up on a 2x4 on its centre stand so it's a bit higher up and put a car battery on the back so the front tire tipped up in the air well clear of the floor. The speedometer wasn't reading anything so I slipped the front wheel forward off the axle bolt and double checked everything.
Sunday, 14 March 2021
Tiger Testing After A Winter of Deep Maintenance
- the swingarm maintenance has transformed the rear suspension! Unseized bearings mean the back end is supple and responsive now
- the front forks and steering feel brand new thanks to fork servicing and pulling the steering apart and re-greasing everything
- the new tires are spectacular! The old Michelins still looked ok but they were badly squared off and made the bike hesitant to turn - it drops into turns like a gymnast now!
- the deep cleaning on the fuel injection system has worked a charm. It idles well and the fueling is excellent.
- the cosmetic touch-ups make the bike look much younger than it's 18 years and over 80k kms
- the new indicators suit the bike way better and work perfectly
- new horn is loud and works well
- I've bled the front brakes and they're tight now, but after repeatedly bleeding the rears they're still not what they were, though they do now produce some stopping power. I need to check for any leaks and bleed again.
- The speedo doesn't show speed! This has never been a problem before. I'm going to check the connection to the gauge because I was knocking it around and might have knocked it loose
- speedo step two will be to raise the front end, remove the front tire and check how I installed the speedo unit - it only goes on one way so I'm not sure how that could be wrong but if the gauge check doesn't do anything that's the next step
- The engine light is on! Though the engine feels fantastic, sounds great and the fuel injection which was problematic last year idles steady and fuels very smoothly. The simple computer in the bike sometimes needs a few runnings to clear an error after a long time unpowered (like the 99 day Canadian winter break we had this long, cold, COVID-winter)
- engine light step two if it doesn't go off by itself is to connect the TuneBoy engine management system I've got and see what errors it's throwing up.
The bike goes and works better than it did in many regards before the winter-maintenance. A couple of details and it seems ready to take on another short Canadian riding season. I'm still hoping to hit 100k the year the bike turns 20 years old (2023).
Photos are all taken with a Ricoh ThetaV 360 camera wrapped around the wing mirror with a flexible tripod. The camera is set to take a photo every four seconds then I just go for a ride and see what I caught when I get back. Photos were edited in the Ricoh software and then touched up in Adobe Lightroom.
Sunday, 22 November 2020
Triumph Tiger 955i Winter Maintenance List
2003 Triumph Tiger 955i winter maintenance list
Chassis Maintenance

Parts List (that I hope I don't need)
- Triumph BEARING NEEDLE 2526 Part # T3800014
- Triumph SEAL, SD 25 32 04 Part # T3600170
- Triumph SPINDLE, SWINGARM Part # T2056007
- Parts List

Front fork oil change and refresh.
Steering hub check, clean, replace if necessary
- Forks & hub parts list
- Triumph FORK SEAL Part # T2040283
- Triumph 'O' RING Part # 2040081-T0301
- Triumph GAITOR,FORK Part # T2040288
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Triumph FUEL INJECTOR, F-TYPE, LONG Part # T1240891 |
- clean fuel injectors?
- how to do that except the first comment is not to backflush a fuel injector as they almost never go bad and this can wreck them
- Royal Purple FI PEA Cleaner
- I think I'm going to go with the SeaFoam I've been using if they aren't showing any signs of leaking
- Motion Pro makes a clamp that lets you force cleaner through injectors, but it's expensive (for a clamp) and I'm not sure it's necessary
- Another FI cleaning how to
- And another is removing and cleaning injectors necessary? Evidently.
- I think I'm going to draw some PEA cleaner through with a vacuum pump and let it soak rather than trying to pressure force cleaner through the system
- I balanced the injectors in the spring with an FI vacuum/mercury system, but I'm going to try it again using the TUNEboy diagnostic system I've got.
LED Indicator Light Upgrade
- replace existing LEDs with heavy metal update
- got the parts in
- kept the original flasher relay so if these aren't LED they'll still work
- put LEDs on it aside
Tire Change
- change tires and inner tubes (either through Lloyd or DIY?)
- https://www.cycleworld.com/how-to-change-a-motorcycle-tire/
- looks pretty straight forward - where can I get tire irons? Tire spoons aren't expensive and are available on Amazon.
- Already got the tires in from REVCO.
- Also have new inner tubes with Counter Balance balancing beads already in them
- chatted with our auto teacher at school, I'm going to have a go at this DIY next week in the shop
Brake Fluid Flush And Fill
- Read the BIKE article on braided brake lines
- done this before on the Concours
- Tiger needs new fluid anyway (3 yrs since last flush)
- Get DOT4 fluid
- replace lines with DISCO HEL lines
Other
Wednesday, 12 August 2020
Triumph Tiger 955i Engine Remapping
If you've never wrapped your head around engine maps, they're not very complicated. Tuneboy does a good job of explaining how it works in their primer that comes with their software.
Back in the day you had a carburetor that used screws and jets to set the amount of fuel that got metered into the engine. If you changed altitude you had to start swapping hard parts (usually the jets that sprayed fuel) to keep the bike running right, and sooner than later you had to manually trim the whole thing to keep it running right. Electronic fuel injection took that all away. A computer under the passenger seat on the Tiger takes inputs from sensors in the air-box (barometric pressure), in each of the three injectors , the fuel pump, radiator (engine temperature) and a crankcase sensor to constantly adjust things to use the most effective amount of fuel to make the bike go. Put another way, carburetors are a mechanical, low resolution solution to feeding fuel into an engine. Electronic fuel injection is a responsive, high resolution fix to the problem of delivering the right amount of fuel to a motor.
Tuneboy map editor - you can change settings and tell the ECU (electronic control unit) what to do under certain circumstances. |
A fuel map is a spreadsheet of numbers. Sensors feed the computer what RPM the engine is turning at and how much throttle is being asked for and based on the number in the fuel map, the computer delivers a set amount of fuel. The 'fuel map' is literally a map that directs the computer to deliver a set amount of fuel. If you're at high RPM and have just shut off the throttle, a smart EFI system will cut fuel delivery entirely, saving both fuel and emissions, something a carb couldn't manage. If you suddenly give the bike a handful of throttle at low RPM, the map will direct the fuel injectors to deliver an optimal amount of fuel as it picks up speed, whereas a carb will always just send a mechanically set amount of fuel based only on how much wrist you're giving it.
In Tuneboy's system, you can change fueling and ignition maps, and modify things like idle speeds. The issue has been that the only maps I can find for Tuneboy are the stock ones from Triumph, which were set up to favour fuel economy and emissions over smoothness and drive-ability. Meanwhile, TUNEECU (if you can navigate their 90's style web design and atrocious apostrophe use) offers you modified tunes that can smooth out your lumpy OEM map.![]() |
Even though the old vacuum pipes held vacuum, I swapped them out for some similarly sized clear fuel line I had (you can see them going from above each injector to the idle stepper motor. The TUNEboy software also comes with a diagnostics tool (with very cool 90s graphics!) that lets you test the radiator fan, idle stepper motor (which moves up and down modulating the vacuum in that black thing to the left/bottom in the picture) and the RPM gauge. LINKS You can find TUNEboy here: https://www.tuneboy.com.au/ It comes with a cable that'll connect to your Triumph and is easy to get going, and comes with all the stock tunes. It also lets you tune on a dyno, if you're minted. It ain't cheap, but the minted guy who bought my bike new was, so he sprung for it and I'm still enjoying his largess over a decade later. TuneECU can be found here: https://www.tuneecu.net/TuneECU_En/links.html Try to get past the out of control apostrophe use - they're better at software than they are at the speaking English goodly. The older version is free, but finicky with Windows' old serial port drivers. You can buy the app on the Android store for fifteen bucks, which seems perfectly reasonable. You can then connect via bluetooth from a phone or Google tablet, though I understand you miss some connectivity that way. It gets tricky these days finding the On Board Diagnostics (OBD) serial cable you need to connect the bike to the PC. You can buy 'em from the UK, where people like fixing things. CJ Designs in Wisconsin will sort you out with one too: https://cjdesignsllc.com/?s=TuneECU The modded engine maps for Triumphs on TuneECU can be found here: https://www.tuneecu.net/Custom_Tune_list.html The TuneECU page goes into detail about how you might use the TUNEboy cable, but it requires so much messing around with knocking default Windows drivers out of the way and forcing others on that I wouldn't bother (I didn't). |
Sunday, 2 August 2020
Tiger Brains

Once I got them in I fired up the TUNEBOY software and figured I'd run the idle control system test since it would move the plunger up and down and with everything off I could check to see that it's all working as it should, except the ECU wouldn't connect to the computer. I've done dozens of TUNEBOY adjustments now and know how the bike syncs with the PC over the serial port, but it wasn't connecting. While trying some variations I turned the ignition on on the bike and the ECU made unfamiliar popping noise, and then none of the dash lights would come on (the running lights still do though). The ECU no longer clicks off when the ignition is switched off either, which suggests it's not coming on either.
The intermittent nature of this failure always made my ass twitch in terms of it being electronic rather than mechanical. Mechanical failures tend to be more consistent and easier to diagnose, and I've replaced everything around the idle control system now, so unless Triumph sold me a dickey idle control motor, which seems unlikely since the first one lasted 17 years and did over seventy-six thousand hard, Canadian kilometres and survived seventeen -40°C Canadian winters. Assuming all the new parts are working as they should, an ECU that was losing the plot is as likely a culprit as anything else I've been chasing, and now it seems to have popped entirely.
So what do you do when your old Triumph's bike brain loses the plot? Get another, I guess. Used ones seems to be extraordinarily expensive and look to be in rough shape out of US used parts suppliers on eBay. And for some reason they're charging twice what European suppliers are for shipping. With that and the fact that The States seem like they're on the edge of a civil war, I think I'll be looking to the dependable Germans who have COVID19 well managed for a replacement Tiger brain. If I'm thinking that, I wonder how many other people are avoiding business with the US right now.

The most frustrating part about this is that I may well have solved the idle problem with replacement hoses, or maybe I didn't. Maybe I chased down all of these hoses and parts for nothing and it was the ECU losing the plot all along. Electronic Fuel Injection (EFI) is a wonderful thing, but the early systems were fragile. There a lots of posts online about early Triumph EFI headaches, and I've added to them.

Early fuel injected bikes are a lot like that Vulcan - they can do things earlier bikes can't like get better mileage, not need parts changed to ride at altitude and generally require less maintenance. I just fixed up one of the last carbureted bikes, a 1997 Honda Fireblade, over the winter. EFI was around then, but Honda wisely went for highly evolved carburettors rather than new, fragile and poor performing EFI systems. I rebuilt the carbs, which are a complex but highly evolved four-carb set, and the bike runs like a Swiss (or rather Japanese) watch. The EFI on the Tiger did the job without any attention for 17 years and seventy-six thousand kilometres including two rides into the Rockies - something no carburetor could do, but when it finally broke, boy did it break. It's things like this that will make these first generation EFI bikes rare in the future. Like the Vulcan, they're so complicated and difficult to maintain when they go wrong that they'll get retired from service where an older, simpler bike might still be fixable.
RESOURCES FOR CHASING DOWN ECU PROBLEMS ON A TRIUMPH 955i MOTORBIKE:
https://www.ebay.com/itm/Triumph-Speed-Triple-955-2000-2004-ECU-Steuergerat-CDI-S1000T3/324154967093?hash=item4b79244435:g:BCEAAOSwZrteryUL
There are early Triumph EFI issues aplenty online:
https://www.triumphrat.net/threads/ecu-repair-refurbishing.525873/
https://www.triumphrat.net/threads/bad-ecu-on-my-2006-speed-triple.159082/
https://www.triumphrat.net/threads/955i-idle-hesitation-porblem.971699/#post-2004081361
https://www.triumphrat.net/threads/ecu-unit.80778/
https://www.thetriumphforum.com/threads/s1000t3-ecu.22000/
https://www.triumphrat.net/threads/1999-955i-ecu-needed.93566/#post-1107942
Used Parts, not of the vintage I'm looking for though:
http://www.rubbersideup.com/triumph/tiger?p=2
https://www.bikebandit.com/oem-parts/detail/triumph/t1291000/b1389042?m=121594&sch=565828
Wahay! A new ECU is two-grand, AMERICAN! That's over $2500 Canadian! The whole bike cost me three grand. See what I mean about the costs of keeping emerging, fragile old tech active?
Saturday, 18 July 2020
Triumph 955i Engine Stalling: next steps
Looking up the issue online, intermittent stalling on a Triumph 955i engine seems to be an issue. I've replaced the idle control system and tested the vacuum tubes again (no leaks), so I don't think that's the issue. It might be a sensor that doesn't return information consistently, but there are a lot of sensors feeding the computer that controls the fuel injection, so unless the bike is showing an error, I don't want to start replacing them willy-nilly.
The bike does occasionally show errors on the Tuneboy Software that came with the bike:
July 1st it showed:
P0113 Intake air temperature sensor
P0230 fuel pump relay fault
P1231 fuel pump relay open
P0463 fuel level sensor input
P0505 Idle control system malfunction... but then they all seemed to go away and the bike was running well when I left for the long ride last weekend (over 800kms over 2 days), at least until I was riding home at the end of it when the intermittent stalling returned. It was showing this again this week:
I'm not sure that the air temperature sensor would be enough to stall out the engine, but this at least gives me a couple of things to look into: that air temp sensor and the fuel level sensor (though again, that shouldn't affect the idle).

I balanced the throttle bodies with it, but the stalling persists. I'm now looking at the mapping for the bike in addition to keeping an eye on errors that might pop up. This video uses Easy Tune, which I haven't monkeyed with, but gives the impression that early Triumph electronic fuel injection was a bit of a mess and many dealers don't know how to resolve it:
That's a bit worrying because if I'm still stumped I was going to take the Tiger down to Inglis Cycle and have them resolve this with some factory testing, but if I'm going to pay dealer rates and get the bike back still stalling, that's not cool.

I think I'm going to go back and look at the fuel pump relay and the wiring for it as an intermittent fault there would starve the engine and cause stalling. Less likely are the air temperature sensor and fuel level sensor, which have been a bit whacky with the fuel gauge going from full to empty and back to full again, but I don't see how that could cause a stall. If there's gas in the tank, the engine will use it.
My order of operations is:
- fuel pump relay (which might have gotten wet at a recent cleaning, so it's on my mind)
- fuel level sensor
- air temperature sensor
If they aren't crazy expensive, I might just get all 3 new rather than paying shipping x3, which would probably cost more than the parts.
NOTES:
https://www.triumphrat.net/threads/955i-engine-stalls-need-help.16567/
"throttle slides were out of balance"
https://fortnine.ca/en/tecmate-carbmate-synchronizer-ts-110
fuel injector/carb syncronizer
https://en.vindecoder.pl/L4PLUMC0662000046
vin looker upper if you're wanting to confirm year and make
https://tuneecu.net/TuneECU_En/install1.html
'free' ECU tuning options for Triumphs - early FI Triumphs seem to have a number of issues
https://www.youtube.com/watch?v=QvHqNeClz2U
video guide to TuneECU (I can't stand online how-to videos, I prefer text. Waiting for 30 second intros each time drives me around the bend, but maybe you like that
https://www.ftdichip.com/Drivers/D2XX.htm
chip drivers for FTDI cables
https://www.r3owners.net/threads/tuneecu-with-tuneboy-cable.7856/
Using a Tuneboy cable with TuneECU
https://www.triumphrat.net/threads/cant-get-tune-ecu-app-to-connect-ugh.962476/
connections issue with TuneECU (I found Tuneboy pretty straight forward, but it's a more expensive option that I'm using only because it came with the bike)
https://www.bikebandit.com/oem-parts/2003-triumph-tiger-955i/o/m121594#sch565841
Parts diagram for a 2003 Triumph Tiger 955i focusing on the EFI relay (it's under the seat) Triumph RELAY, EFI Part # T2502109
Sunday, 14 June 2020
One Tight, Not Too Tight
That philosophy is at odds with the heavy handed git who owned it before me and managed to maintain it into such a state of disrepair that it kept it off the road for years.
From the rear brake cylinder that was assembled backwards and over tightened, to the over tight wheels and the slipping clutch I've just adjusted to actually be at spec rather than over-tightened, I'm finding the Honda was a victim of a heavy hand and unsympathetic mechanical inclination.
When I was a teen my dad was talking me through a head gasket repair on one of my first cars. We weren't minted, so the only way I was driving was if I could keep an old car on the road; mechanical training was an implicit part of vehicle ownership for me growing up. As we were tightening the head back on he made a point of talking me through the bolt pattern - always tightening opposite bolts so it would seat evenly, and then said something that I've never forgotten as we started tightening down the head: "always one tight, not too tight." I guess the guy who abused this lovely piece of Honda engineering into years in a garage never got such good advice.
Mechanical sympathy is an important part of maintaining any machine, but especially a motorcycle, where if you are cack-handed you can end up seriously hurting yourself when it breaks. In that way, motorcycle mechanics are a lot like aircraft mechanics, it's a do it right or it can go very wrong kind of situation.
Part of that sympathy is taking the time to understand what the engineers who designed the machine want you to do in terms of looking after it. In the case of the CBR900RR, Honda would like you to leave 10-20mm of play at the end of the clutch lever - this one was set so you could strum it like a guitar string. This play is to ensure that the clutch fully disengages when you let go of it. An over tightened clutch cable means it's always set to be slightly pulling and engaging the clutch. Making it too tight isn't just a failure of the hands, it's a failure in thinking that wounds the machine. In this case, the over-tightened clutch cable explains why the 'Blade was slipping RPMs when I opened it up. A sympathetically tuned motorbike will give you a purity of interaction that allows you to more fully understand the machine. This is one of the reasons why I value technical fluency so much, it puts your ability to operate technology into focus in a way that the technically ignorant will never realize.
***

One of the nice things about the Tiger is that it's fuel injected, so all that carburetor management is taken care of, but the evil end of computerized fuel injection is that after seventy six thousand kilometres it's finally gone wrong, and an electronic system like that can go wrong in a lot of different ways.
I'd never gotten into the Tuneboy Software that came with the Tiger (the original owner installed it along with a Power Commander), because if it ain't broke, don't fix it. But now that it's broke, I got going on it the other evening. Getting into the bike via a computer was pretty cool. The software is Y2K retro-hip and the connection was straightforward. The 20+ pages of instructions weren't really needed (I'm handy with computers). Windows 10 automatically recognizes what you're plugging in (back in the day, WinXP would have needed drivers installed), and the software is responsive and quick to connect. It occasionally drops connection, but unplugging it and plugging it in again resolved that each time.
The compact disk (told ya, Y2K hip!) had all of the stock maps for my year of Triumph Tiger 955i engine on it, so I saved what was on there in case it was some kind of cool specialty map the previous owner had worked out (dude worked at a nuclear power plant, so don't underestimate his tech skillz), and then I flashed it with the stock numbers, which took about 20 seconds and returned a confirmed result. There is a slight lag, but otherwise this is easy to use stuff.

The problem with an idle fault on a fuel injected bike is that the engine management system is taking in data from a number of sensors and using it to balance engine activity, like idling, based on that information. I've got the mechanical component that regulates idle on the bike incoming, and I hope that resolves the issue, but what I fear is that it's something else, and with these complex electronics systems could mean that anything from a dozen different sensors or relays to a loose or broken wire. With any luck, it's that idle air control valve and I'm back on the Tiger... and the Honda, just not at the same time.