Saturday, 17 May 2025

Tiger Test Ride(s)

 The Tiger rode like it has never had any fueling problems after I hacked the idle control system last time. Idle control is a common problem on 955i Triumphs and I've spent years trying to get mine back into spec even as finding parts for them gets more difficult. Turns out the solution is to remove it.

Ride #2: 40 minutes locally

Second ride this week and the bike idles rock steady and is as smooth as it has ever been, and the backfiring that had been getting worse is completely gone. Today it started on the button, ran from cold with no issues and took me on a 40 minute ride without a hiccup.

We live in an overcrowded little town now thanks to Southern Ontario swelling in size post COVID, so I took the Tiger through a lot of stop-start traffic to see if I could get it to hiccup, but it wouldn't! Makes me want to move more than ever though.

No problems on the back roads.

Pickup up from stops, no problem. Cornering roll on throttle? Smooth as butter. Idle never wavers and I'd forgotten how much fun to chuck around the Tiger is...


So if you're having never ending headaches with your Triumph 955i idle control system, yank the damned thing! Modulating the idle through varying the vacuum between the intake manifold and the airbox (the servo moves up and down revealing the vacuum passages for the three throttle bodies) serves some purpose (perhaps emissions?), but at this point in the bike's life at over 90k and 22 years in, removing the lot and connecting the intake vacuum lines together offers a viable fix for what may be one of the last of these bikes on the road in Canada. I'd be willing to play Top Trumps with any other 955is on mileage too.

Ride #3: Going Long

The next run was a 275 km run up to Georgian Bay to look at a blue horizon. These days it's also a reason to get out of our increasingly overcrowded and traffic jammy town.

The first 45 minutes are straight lining through farm desert, but the geography starts to get some character once you get into the Niagara Escarpment in the Gray Highlands. I didn't throw the 360 camera on until we got to the less tedious bits.

At just under half a tank the Tiger took me 140 kms and two stops to a fuel stop between Blue Mountain and the big water. It was still showing most of the red on the fuel gauge and took less than 17 litres (it's a 24 litre tank), suggesting that this mod isn't hurting mileage.

After the fill up it was some twisty bits over to Creemore for a bite and then the long haul back through farm desert (with its big, juicy flies) and then lines of traffic to get back to my driveway. Through it all the Tiger was mighty.



Flesherton to Thornbury through Beaver Valley (41kms)





Thornbury Harbour to Creemore Brewery (77 kms)



Thornbury Harbour!

Just past the scenic caves on Blue Mountain.

Creemore for a late lunch.

Steady 100km/hr sections, twisties, as big an altitude change as you can find in Southern Ontario and we never missed a beat. Left at 10am, got home just past 4pm, multiple stops, always started on the button whether cold, or or somewhere in between.Temp was mid-teens leaving and mid-twenties returning.

It's been a while since you've heard this on here, but I'm a happy Tiger owner.


1) Bin 2, 3 and 4
2) Remove the top of the servo (1) and leave it plugged in but detached from the airbox.
3) Block off the hole in the bottom of the airbox left by the removed idle control stuff..
4) Plumb the three vacuum lines out of the throttle bodies into each other through a T-junction.

Bob's your uncle! No promises, but it did the trick for me.

Saturday, 10 May 2025

Triumph 955i Stalling Issues.... Fixed!?!

 Facebook slapped me in the face with this this morning:


...so I went on a mission.

I pulled the tank (for the millionth time?) and set up the 955i Triumph Tiger so I could try many different things to test if the idle was working. Previously I'd followed the manual, but no longer!

I did the usual checks for vacuum leaks and I continue to suspect the overly complicated and no longer supported idle control system. After trying everything I'd tried before, I decided to go OFF BOOK.

If I can't fix this @*&%ing thing perhaps I can hack it! With the bike in test mode (plugged in and ready to run with all sensors attached), now is the moment to try some alternatives, so I pulled the entire idle control system and tried variations without it.

I plugged the servo back in because I figured leaving it unplugged might piss off the computer. I also removed the end of the servo so it wouldn't interfere with the airbox and then blocked off the airbox with Gorilla Tape.

I'd also done my due diligence by balancing the throttle bodies and making sure everything else was plugged in as normal. I also reflashed the computer through Tuneboy with the South African map I found a few years ago.

 So what happens when you remove the entire (problematic) idle control system in a Triumph 955i engine and simply connect the vacuum tubes out of the throttle body to each other?

Well, it seems to have fixed everything. The bike idles right where the computer sets it, the backfiring problem is gone and the motor fuels smoothly (though this is probably in large part due to that fantastic South African fuel map). Best of all, no more stalling.


That's the work around. I got some silicon tubing from Amazon along with some T connectors (maybe $30 all in?). The last round of Triumph replacement parts cost me north of $200 and when I had to start buying used parts (because Triumph has stopped supporting their own bikes) and getting them shipped over to Canada it cost even more... but this hack is thirty bucks in parts and I also have a pile of unused silicon tubing and T connectors left over. I attached the silicon hoses to the T connector and then into each of the throttle bodies, so it's a closed loop with no chance of leaks.

In the pic you can see the idle control servo (black object above the intakes on the left side). That's what it looks like with the plunger removed. It still moves up and down but has nothing to do with moderating vacuum between the airbox and the throttle bodies which is what has caused me years of headaches.

I'm so jumpy about the motor falling through idle and stalling (it's a perilous place to be when you're on the road on a bike that keeps cutting out), but this hack hasn't just solved the idle problem, it has also resolved all of the other issues. The bike idles steady right where I set it in Tuneboy, but more surprising is that the backfiring that had crept in is completely gone. The bike feels tight, full powered and like it did years ago. My only thought now is that it might hurt the gas mileage, but I'll keep an eye on that as I get some miles under me this summer.


It still starts like normal. I'm occasionally getting a high idle (3-4 thousand RPM), but as I rode it that happened less - like the computer was figuring out the new normal. I'm curious to see if not having that system in affects cold starting but that's not going to be an issue for the next four months, and I don't mind being my own choke if it means a steady idle.