CO settings

[kolonial72]

During a recent tech day, I adjusted my CO settings +7 in an attempt to smooth out the at-idle miss sound and 3400 rpm surging. Didn't quite do the trick. I wanted to add more to the settings, but the settings had been adjusted before, and I didn't know by how much.

A few months ago I took the bike to a shop for some tires. While it was there they installed a Barbarian jumper and did some tuning on a dyno. They made several adjustments to the CO settings. I had not asked for the information on how much they adusted, so I went back today to ask them.

Cylinder: 1 2 3 4

Stock: -2 20 7 16

Shop: -32 -10 -23 -14

Current: -25 -5 -16 -7

So, they took everything -30. That's minus thirty. I saw those and was like, wow. Maybe I'm running a little lean. Since the shop adjustment, I've gotten 38 to 40 mpg, which was my mileage before. And the peak horsepower on the dyno was 125.37, so that seems okay.

The trace of speed versus HP is fairly straight from the start to the peak, except in the range of 70 to 80 mph. That comes out to about 4000 on the low end and something less than 4500 rpm on the high end in 5th gear. In that range there is a bump on the curve. The curve ramps up quickly from 70 to 85 hp between 70 and 77 mph. Then the curve is almost but not quite level at 85 hp from 77 to 80 mph. The curve then behaves quite nicely.

Oh, also during the tech day, I trimmed the plug wires and cleaned corrosion off of the ECU connector under the tank. Neither of these actions seemed to have any effect on the miss/surge. Checked the throttle sync, still good.

I plan to change plugs this coming week. Not sure when they were changed last, but it's the first I've done it in the 4000 miles I've had the bike, which has 15k and change on the odo.

So here's my question. Is running the engine this lean going to be a problem, be it short term or long term? Based on the response, I may adjust the settings back to stock.

 

[Shadow]

Strange, making a lean engine run even leaner.

Most seem to ad 7 to 10 points to each cylinder.

Never heard of removing points.

 

[03HiYoSilver]

kolonial,

How's the heat temp showing? Is it running hotter?

If you run too lean you could hurt the cylinders since the fuel acts as a coolant.

To really get an optimal CO Setiings, fuel injection is supposed to yield CO values of 3.8-4.0% at the header. To accurately test these values, you would need to install Riv Nuts (one at each header). I believe at the factory, the CO settings are set at about 3.3%.

RivNuts part# ACC-11130-00-26 (6mm) RivNuts Installed https://www.fjrforum.com/forum//index.php?showtopic=28571

 

[kolonial72]

Hey thanks for the reminder, HiYo. Probably the surest thing would be to install the nuts and really test the pre-cat exhaust.

I don't believe the engine runs any hotter than it did before the changes. Of course, the ambient temperature in PA is up about 45 or 50 degrees since then....

 

[SPORT]

K72,

That does seem a bit odd. Agreeing with the above sentiments, I would also like to add that the bike 'should have' began to run rougher. As we did our tech day last Saturday I went another +7 making my CO's +14 from stock. Of course I also did the CDogman's airbox mod, but she runs most excellent now.

I am perplexed as to how reducing CO's from stock makes the bike run better???

Just keep an eye on the temp guage and note whether it runs hotter than normal through the summer; if so, I'd consider adjusting accordingly.

BTW, what did the shop charge for running on the Dyno and making adjustments?

 

[Wicked Webby]

Ya...

Sounds like a very lean setup....

What elevation you riding in?

Anything else done regarding the fuel/exhaust?

WW

 

[SPORT]

Ya...
Sounds like a very lean setup....

What elevation you riding in?

Anything else done regarding the fuel/exhaust?

WW

WW,

Were only about 466 ASL and should pose any problems. PA is unlike the Left coast in that our elevation may change 1,200 feet....maybe?

 

[charismaticmegafauna]

<snip>...How's the heat temp showing? Is it running hotter?

The running temperature of the FJR engine is controlled by the closing/opening of the thermostat and the switching on/off of the fan/s.

If you run too lean you could hurt the cylinders since the fuel acts as a coolant.

If you run too rich you could hurt the cylinders by washing them with excess fuel.

Actually, what you want is 'stoichiometric' (abt. 14.7:1 A/F ratio) -- and leaner (or richer) will have lower EGTs (exhaust gas temperature).

To really get an optimal CO Setiings, fuel injection is supposed to yield CO values of 3.8-4.0% at the header. To accurately test these values, you would need to install Riv Nuts (one at each header). I believe at the factory, the CO settings are set at about 3.3%.

You can also use these taps to install pyrometers to measure EGTs.

Lean (lean-burn) is good for most everything: engine, environment (NOX excepted), etc?.

Driveability: now that's something else, altogether -- and depends on operator, engine & vehicle design, ambient temps, altitude, fuel, and a myriad of 'variables'. The FJR's ECU and Lambda sensor adjusts for all that (in most cases).

If you're unhappy with your FJR's driveability....?, you need to either: BJ mod or (something-like) a Power Commander....