Co Mod

[local40]

Anyone done the co mod? Was it worth it and would you do it again? Also did you find any long term affects?
Thanks!

[rbentnail]

Gazillions have done the Barbarian Jumper Mod. it's the Bee's Knees!!

[ionbeam]

Anyone done the co mod?....

Actually, in the past 14 years nobody has ever done the CO mod. Err, well, perhaps only a thousand or two. Or more.

It was originally done to 'fix' lean surging. The guys that first did the mod (Tom Barber/Barbarian and Dwayne Verhey/Torch) also installed 4 rivnuts into the exhaust headers (internally threaded bungs swaged to the pipes) and used an EGA (Exhaust Gas Analyzer) to set the CO levels. They were set so that the exhaust out the muffler tips (post cataclysmic converter) was a tiny bit under 1.5% CO which meets all EPA exhaust standards. The readings at the head pipes were 4%-5% CO, pre cat con readings. There was no guessing and the setup was correct for only that one 2003 FJR. All year FJRs after that didn't make quite as much OEM HP which indicates the tuning of the '03 was different so the CO levels that the guys changed were unique for that one bike & that one year. Anything you do with the CO levels is just a guess and a hope unless you bung the head pipes and use an EGA. And finally, the CO adjustment is primarily a setting that affects FI at idle and just off idle and really doesn't have much effect at higher throttle settings.

When the CO level is offset in the positive direction the fuel injection shot is slightly enriched which causes the engine to slightly 'bog' due to excessive fuel. The overly rich condition causes the throttle response to feel softer (because the engine isn't running as good as it should) and it helps to reduce lean surging. Gas mileage normally goes down a tiny bit and the plugs turn black over time (due to richness). Extra fuel can wash oil off the cylinder walls too.

A DynoJet Power Commander (PC) gives you access to the full RPM range and lets you offset the fuel mapping with a wide range of +/- values. It also offers a digital 'accelerator pump' feature for those times were you whack the throttle open. Unfortunatly, the FJR does not and never has let you adjust spark mapping. The PC shows you a full RPM map on you computer screen and lets you do your programming and then download the custom FI maps to your PC. There are also a number of pre-made maps. Ideally, you would take your FJR with the PC installed to any DynoJet shop which has a DynoJet chassis dynamometer. You make a number of full throttle pulls on the dyno and then it spits out a custom FI map tailored specifically to your bike and your comfort/performance goals.

[local40]

How important is it to unplug fuel pump before entering dinostic mode?

[ionbeam]

How important is it to unplug fuel pump before entering dinostic mode?

You don't have to do this for Gen I or Gen II FJRs, simply hold the buttons and turn the key on.

[local40]

Thanks Iobeam. I think I will leave it be.

[local40]

On number 62 it shows a number 2. The way I understand it that is a ambient air sensor. I have a surge at start up but goes away when warm. Do you think there is a connection?

[ionbeam]

Thanks Iobeam. I think I will leave it be.

Sometimes the most good you can do is to do nothing

Do check your throttle body synch if you haven't done so yet, it can sort out a lot of little niggling things. If your problem is not so much lean surging but vibrations I can link you to a "Really, Definitely, Completely Un-Authorized Throttle Body Sync" procedure which does help vibrations, and in spite of the name given to the procedure it is safe and proven effective with no negative side effects.

[local40]

Sure. I would love to look at it.

[ionbeam]

On number 62 it shows a number 2. The way I understand it that is a ambient air sensor. I have a surge at start up but goes away when warm. Do you think there is a connection?

Yes, that is the atmospheric pressure sensor that lives under the seat (on your Gen I) and is attached to the bottom of the cross brace.

I really doubt that the sensor is a problem. FWIW, if the sensor is unplugged your FJR ECU will use a lookup table and run just fine. If the sensor is out of range it will run like s#it all the time. The atmospheric sensor is exactly the same as the intake pressure sensor on the left end of the intake manifold and the two can be swapped. Clear the code and see if it ever comes back.

Of course Yamaha has to display the pressure reading for the ambient sensor in a bohemian unit of measure. You would be looking for a reading like 0.98 on the diAG readout screen. If it reads correctly, then it is working and will be correct across the full range. One atmosphere, at sea level, at room temperature can be measured in several different ways.

Perfectly, one atmosphere is 760mm Hg. In countries like the US & England that use wonky units of measure, one atmosphere = 29.9 inches of Hg or 14.7 PSI.

752mm HG is 29.6" HG

752mm HG is 14.5 PSI.

752mm HG is 0.98 atmosphere

[local40]

Iobeam you are the man. Thanks for your help!!!

[local40]

Ionman I show 98 on the sensor. How the heck do you know all this?

[wheatonFJR]

Ionman I show 98 on the sensor. How the heck do you know all this?

Ionbeam was placed here on earth in the year 28BC by aliens to provide knowledge for future FJR owners. He's been here a loooonnnng time.

[local40]

I believe that Wheatonfjr.

[ionbeam]

...Do check your throttle body synch...I can link you to the "Really, Definitely, Completely Un-Authorized Throttle Body Sync" procedure which does help vibrations...

Sure. I would love to look at it.

My friend and riding bud Fred W (FeeJeR Fred here on this Forum) wrote the unauthorized procedure. It's been done a lot and never had a problem. You can read the procedure here.

[Uncle Hud]

Thanks, Professor.

[0face]

Ionman I show 98 on the sensor. How the heck do you know all this?

Ionbeam was placed here on earth in the year 28BC by aliens to provide knowledge for future FJR owners. He's been here a loooonnnng time.

I just actually laughed out loud ya bastage!




Sent from my iPhone using Tapatalk

[gixxerjasen]

Best Co mod you can do with your bike. Does nothing for your bike but does much for you.