Rough Idle + Dying at low RPM

[brixtonanimal]

Unfortunately my last post was 2 days ago, problem solved and onto the next one. I’m going to try to document as much as I can about the problem I’ve experienced. If anybody has any feedback, i would find it tremendously helpful, if not, i’ll Keep updating as i work through the problem.

Current behavior: The bike intermittently idles roughly. This happens after the bike is warm, but not on startup (even if warm). When coming to a stop, the bike idles alright, then after a few seconds of sitting the rpms begin to bounce between 450-950 in 1 second intervals. If I give some throttle, the idling returns to approximnately 900rpms, and then sets back into rough idle after a bit more time. The bike has died one me one time after accelerating and pulling in the clutch to downshift; on this instance, i had the clutch pulled in for longer than normal giving the rpms time to drop all the way down.

Previous behavior: An unsolved problem that has been going on for a few years, hasn’t returned but seems to be related - the bike would shut off on the road when i pull the clutch in for a few seconds. This would typically happen when warm, and often after parked for a bit. An example is if I would go into a restaurant and come back out after the bike had been sitting. It would fire up just fine and a few miles down the road the rpm’s would fall extremely low when it should have been idling. It felt very similar to vaporlock that I’d experienced on old carbureted cars.

I have heard that a potential problem may have been something to do with a thermostat, perhaps the bike is reading a false temperature, not sure.

Any advice in diagnosing the problem would be helpful, I’d love to get it sorted before the issue becomes larger.

Robert

[wytfut]

Do you have the super X tune?
If do... I'd hook up and adjust the leakage....... You may have to tweak it up a touch. I'm still not a electronic fuel injection expert, but we had to do that on both of our Xs this past year with very similar symptoms.
I'll be watching for a reply....

My other possible is a fuel issue. As in old, or a partial plugged injector.

Lemme know
Bruce

[brixtonanimal]

Thanks Bruce, I do have the tune, I’ll talk to the mechanic about getting that adjusted. Separately I will look at the injectors too.  Thanks again for the help

[blackheart]

On my bike the idle air control valve has never worked well. Typically it would idle extremely high rpm then every once in a while it would idle at extremely low rpm.  Mine has never died but also has never worked correctly has about 15k miles now.

I'd say your issues sound like idle air control valve.  Atlantic doesn't carry them.   Eventually I plan to blank mine off permanently and adjust the throttle position to maintain a 950 rpm hot idle.  Actually I will probably blank the air passage and drill an orifice in the blank for the correct speed such that the zero position of the throttle doesn't change much.

[brixtonanimal]

It looks like this triumph idle control valve would be a direct replacement. Is that a difficult job to replace?

Idle Air Control Valve 2699-0036 Triumph #T1240888 - not verified

[wytfut]

The triumph AIC IS NOT a direct replacement...
Sorry....

You may find one that is identical, but it will not be calibrated for our Xs

U can remove it and clean it up. Take it off and cycle it. If it does sound nice and smooth cycle... It need cleaning.

Be very aware to have piece held in garbage bag or can when fooling around with it. The plungers are notorious for blasting off into the putter limits.

Rich..... Did you ask just recently? Curious since we got a flood of parts in ...

[blackheart]

No that was about a year ago Bruce

[brixtonanimal]

Wanted to follow up on this one - I do have the current super x tune with all relevant updates performed. I am thinking that maybe the following things are happening:

- Vaporlock, has anybody encountered this issue on these bikes?

- Plugged injector - could this be a symptom only when warm? I'd think it would always be present

The bike fires right up when cold, and only intermittently has this issue. It really seems that the engine is starved after it's been sitting warm.

[wytfut]

I'm hoping with the super X tune you have, so you can hook up, and read it.
We need to try and tweak the leakage a bit higher.
I can explain step by step...

Haven't heard from you so long, didn't realize your X was still having problems

Bruce

[brixtonanimal]

Yea it’s super intermittent so it’s not top of the priority list (doing some carb work on another bike) but it keeps me from riding it long distances. Do I need any special tools to adjust the leakage?

[rt66john]

You set the leakage using the Super X Tune program on a laptop while it's connected to the bike's ECU.

[wytfut]

Exactly John...
Robert.... no tools required... just your computer and your cable plugged into your OBD port under the seat.
first up... sorry not a quick reply..
Been battling a dose of food poisoning since friday, then yesterday, fiber got cut in our area...

So first up Robert, were you a early purchaser of the superXtune where as you got the CD, and cable included.... and the password/key?

If not, there is nothing much more I can do here but make some slight suggestions.  If you had your ECU flashed by someone....    I'd be calling Jamie with him.

Being "super intermmittent", it could be as simple as a different or poor grade of fuel.
For example when I went to Virginia for one of the events years ago, I filled up on a gas pump no one else was using..... the rest of the time I was there, it was dying constantly, until I got enough good fuel in it to help it out.
I again saw this with Dennis Bennetts DWS in Arkansas 2 years ago.
This this past July, I filled up in Minnesota for the 20th birthday, and my bike again starting dying at idle, but only occassionally. Quit by the time I got home, as I had diluted the fuel enough, that it stopped.
so there is that also to look at.

Adjusting the "leakage area" is very simple.... and as our bikes age and gasoline changes, there will be more adjustments to be made....

if you have all the goodies Robert... let me know, I'm ready to explain how it all works...
Bruce

[brixtonanimal]

Hey Bruce, thanks for the detailed reply. I don't have the CD, and think I just had the flash performed, but I'll have to go through my files and see. I definitely don't have a cable for it. I'll call Jamie and see what can be done.

The bike dying is very intermittent, but the pulsating idle (between 500-900rpm) is constant once the bike is warm.

Robert

[brixtonanimal]

I noticed my fuel hose is sitting on top of the engine, I bet vapor lock was causing the shutdown after sitting. An easy fix, so I’m going to hope that’s my issue

[wytfut]

sounds reasonable....
good luck