The Yamaha Road Star Warrior Forum

OK, mates. I am not really keen to stir this up again and do not want to stand up as an “Eletric no 2” (LOL) but I have read enough about this ECU Bump business.

Myself, I went through extensive and meticulously experimentation on this matter. My bike was at that stage stock (no BAK) and just had this loud Jardin exhaust I inherited from the previous owner.

After bumping up +3 then a long run, another +3 etc, there was no evidence on my plugs demonstrating any improvements in colouring. They were predominantly whitish and trust me I now how a brownish looking plug is supposed to look. The only thing I noticed was a change from this metallic bright sound on that exhaust to a deeper/throaty sound but just at idle.
I then left it because I was convinced that a PC-III will do more than I was expecting from this anyway.

I recently put a negative commend about this mod declaring it as a busted myth and because I was sick of it, I flicked an email to our technical support from yamaha-motor.com.au with the following content:

In opening the loop wire (pin #27 and #29) on the ECU and attaching pin #29 to mass, followed by the instructions documented in the Yamaha Service
Manual (holding down both button "Select" and "Reset" on the tachometer and then turning the key to "On"), the device turns into an enhanced
diagnosis mode.

Continuing to hold the buttons down will display the "DIAG" and then pressing "Select" it will switch to the symbol "Co" further leading to "Co
01" and "Co 02". In this mode you can make changes to the air/fuel mix of the according cylinder.

My question here: Does this change offset the entire stock A/F map or just the idle settings?

Thanks and regards,
Jack

Answer today:

Dear Jack,

Thank you for resubmitting your enquiry, the CO adjustment through your instrument/ display will only affect idle fuel mixture.

Regards,
Duilio Pianca
Customer Relations Department
Yamaha Motor Australia

Now, with this in mind, once and forever, I declare this ECU Bump again a myth and as busted!!!

Well I'll be.  I've been telling people behind the scenes that I think it affects the rpm range because it makes sense reading the service manual description.  I guess the guys who did the on-the-fly bumps on the dyno are right.  I wonder how it can be when there are so many guys out there with years on a bump and good plug color.  I candidly don't know what to say.

Can somebody do the same enquiry at the US web page (yamaha.com)?

If you plugs were still white after a +3 bump then another +3 bump the bike is still lean. It would depend on where the factory had the ECU CO set to begin with. If  it was like my bike when I got it with 1 mile on the speedo, one of the cylinders was at -8. If I used your guide & added +6 to that cylinder it would still be at -2 & still be lean & the plugs would still be white.

A couple of points of adjustment is a fine tune adjustment, you need to take a big swing at the CO adjustment.

I really don't care what some guy flying a desk at Yamaha has to say about it, bumping the CO is an adjustment across the entire rpm range. PERIOD.

The system is basic speed density which operates in open loop. It does not have the ability to change the fuel mixture on its own because it does not have an 02 sensor. It also does not have an idle air bypass system except for the LCV which is operational by temperature only & not based on a pre set rpm parameter. If the ECU could read the rpm at idle & if it had an full time idle air bypass valve the ECU would control the idle speed. The ECU does not have the ability to tell what rpm the engine is at with the exception of the rpm limiter. The fuel delivery is controled by engine & air temperature, throttle position & air & manifold pressures & operates on pre programed parameters.

Huh... well put me down for one being fooled. lol.  I thought I was 100% convinced it was through the whole range after bumping ECU up by 6 pts my plugs went from white to very black.  I backed it down 3 and they looked good at the beginning of the summer after a 120 miles.  I think I'll take all my plugs out tomorrow to see what they look like, but I'm gonna side with the experts on this one.

Churchkey:

I really don't care what some guy flying a desk at Yamaha has to say about it, bumping the CO is an adjustment across the entire rpm range. PERIOD.

Accepted. Can you back this up? I will take care of the rest with that fly on a Yamaha's desk... LOL

Churchkey:

If you plugs were still white after a +3 bump then another +3 bump the bike is still lean. It would depend on where the factory had the ECU CO set to begin with. If  it was like my bike when I got it with 1 mile on the speedo, one of the cylinders was at -8. If I used your guide & added +6 to that cylinder it would still be at -2 & still be lean & the plugs would still be white.

A couple of points of adjustment is a fine tune adjustment, you need to take a big swing at the CO adjustment.

I really don't care what some guy flying a desk at Yamaha has to say about it, bumping the CO is an adjustment across the entire rpm range. PERIOD.

The system is basic speed density which operates in open loop. It does not have the ability to change the fuel mixture on its own because it does not have an 02 sensor. It also does not have an idle air bypass system except for the LCV which is operational by temperature only & not based on a pre set rpm parameter. If the ECU could read the rpm at idle & if it had an full time idle air bypass valve the ECU would control the idle speed. The ECU does not have the ability to tell what rpm the engine is at with the exception of the rpm limiter. The fuel delivery is controled by engine & air temperature, throttle position & air & manifold pressures & operates on pre programed parameters.

I'll have to side with CK on this one. I did the bump even after I installed my Dynatek FI Module. It made a difference in power and backfire. I also bumped it without the FI module. Huge difference in performance. I had to bump that sucker up about 10 points per Co# to get it to run with my Samson Ground Pounders but it did make a difference in overall performance through the rpm range.

I'm sure the guy you emailed has never done the ECU bump himself. He's probably just a book geek and has no hands on experience.

Is there any way to measure the pulse-width of the signal going to the injectors? I think that would settle this debate once and for all.

 PhatAzz,

I think you got some bad info. Before I bought the PCIII I adjusted mine and it worked great. Plugs were pretty "white" and it took quite a bit of adjusting to get them a light tan.

One other thing. Most mechanics that are certified on the Warrior are completely unaware of this adjustment, so to think some "desk-jockey" at Yamaha knows about it is assuming a lot. It would have been interesting if you would have asked the question without offering the suggestion that it might only adjust the idle. He didn't know (and perhaps no one in his department did) so he quickly grabbed your suggestion (it only adjusts the idle mixture) as truth.

It's either that or Yamaha doesn't want anyone to know how to do this, and since most mechanics don't know about I'd have to say they don't want it known for some reason or another. 

That's fine with me and all makes sense. I just need some evidence and will slap it on is flying desk. Seriously.

phat-azz:

That's fine with me and all makes sense. I just need some evidence and will slap it on is flying desk. Seriously.

How about this; go bump your ECU up about 20 points per cylider and then take it for a ride to see what happens. Then bump it down 40 from the first bump and take it for a ride and see what happens. That will be evidence enough for you and that's all that matters, right?

I did that awhile back, and also called Yamaha (Star) USA technical, and got no answer.  But I could hear their eyeballs glaze over across the phone line.  You did good work Jack, maybe some of us here can make some headway without getting all bong-ish.

phat-azz:

Can somebody do the same enquiry at the US web page (yamaha.com)?

07midnite:

phat-azz:

That's fine with me and all makes sense. I just need some evidence and will slap it on is flying desk. Seriously.

How about this; go bump your ECU up about 20 points per cylider and then take it for a ride to see what happens. Then bump it down 40 from the first bump and take it for a ride and see what happens. That will be evidence enough for you and that's all that matters, right?

Correct. But this just works for me and since I have a PC-III the train is gone already.

I want this Yamaha desk flyer bringing up some additional info on this. He claims this, now I want to know why?

I have to disagree. I had noticable change bumping +-3.

wyomingwarrior:

I'm gonna side with the experts on this one.

 +1 and the expert here would be Churchkey