Running rich on No. 1

[rocketjohn]

I am betting Triumph made the front cylinder run a little rich to squeeze just a little more oomph out of an engine that is otherwise strangled with leanness to meet emission regs. Seeing as how it always seems to be that one cylinder.

 

[leatal]

It's hard to believe a modern engine with fuel injection and electronic ignition and an ECU cannot be made to burn each cylinder exactly the same?

I don't think so.

Somebody splainit to me!

I actually removed all three injectors from the throttle bodies and attached a clear plastic hose to each to observe the fuel flow. All three injectors fired at the same time and seem to inject at the same pulse length (although impossible to measure exact pulse length with naked eye). I'm guessing Triumph doesn't bother with the sophistication required to adjust different pulses for each cylinder and simply has them all fire the same pulse length at the same time. If you are worried about the rich condition, you can swap #1 injector with #2 injector, clean the header flange, run it awhile and check to see if the rich condition moves to cylinder 2. Or if you have a few miles on the bike, get them all professionally cleaned, rebuilt, and flow tested. Relatively cheap at about $18.00 each including O-rings and injector grease.

 

[Rocket3Pilot]

I actually removed all three injectors from the throttle bodies and attached a clear plastic hose to each to observe the fuel flow. All three injectors fired at the same time and seem to inject at the same pulse length (although impossible to measure exact pulse length with naked eye). I'm guessing Triumph doesn't bother with the sophistication required to adjust different pulses for each cylinder and simply has them all fire the same pulse length at the same time. If you are worried about the rich condition, you can swap #1 injector with #2 injector, clean the header flange, run it awhile and check to see if the rich condition moves to cylinder 2. Or if you have a few miles on the bike, get them all professionally cleaned, rebuilt, and flow tested. Relatively cheap at about $18.00 each including O-rings and injector grease.

Yes, I agree that would be the logical test but it seems that the implication is that all Rockets are rich in #1 cylinder? So it's not likely that they all randomly have richer injection in #1.

 

[leatal]

Yes, I agree that would be the logical test but it seems that the implication is that all Rockets are rich in #1 cylinder? So it's not likely that they all randomly have richer injection in #1.

Maybe the injectors fire as #1 is on the intake stroke while #2 and #3 intake later in sequence (after the injectors have already fired)? Maybe #1 gets full gulp of vapored fuel and #2 and 3 get less and less; so #1 runs rich, #3 runs lean, and #2 runs just right? Nothing we can do about it except to avoid excessive idling and keep her revved!

 

[Rocket3Pilot]

Maybe the injectors fire as #1 is on the intake stroke while #2 and #3 intake later in sequence (after the injectors have already fired)? Maybe #1 gets full gulp of vapored fuel and #2 and 3 get less and less; so #1 runs rich, #3 runs lean, and #2 runs just right? Nothing we can do about it except to avoid excessive idling and keep her revved!

Interesting theory. One of our many Guru's should know whether the injectors all fire at once or independently as necessary?

 

[TURBO200R4]

i would guess that they would fire when the intake valve starts to open and quit when it closes.

 

[Paul Bryant]

This is an interesting subject.
No one is going to know any of this unless they remove the header.
In future I am going to ask people to report back to me what their Exhaust ports look like when they fit one of my Headers.

 

[barbagris]

Of course - With a PC5 - the enterprising R3 owner COULD consider tuning by cylinder!.

 

[kipper]

Tuning by cylinder already done on mine.

 

[Mittzy]

I have never noticed any of my cinders running anything but black pipes