Co Adjustment Question

[BlueBullitt]

I did the CO adjustment. My original settings were 5,6,6,17. Not knowing what these numbers mean, the other board said the differences were normal. I bumped each 7 points. I was wondering what stock settings some of you had from the factory, if they are different, and if any one knows why #4 is so much higher. Thanks.

 

[jbay]

My stock settings were 6, 3, -4, 4

A difference of 10 between #1 and #3

 

[radman]

It varies all over the place, don't look for orderly progression in the stack. And bumping 7 arbitrarily may not be the best plan. Frank seems happiest only 3 higher than stock, less in hot weather, more in cold. The only real solution to all this is, I'm convinced, is with a Power Commander, my next purchase.

 

[BlueBullitt]

Has anybody tried evening them out? or do you always add the same to each cylinder?

 

[ionbeam]

It would be very unusual for all the cylinders to have the same CO trim value. Making them all the same is probably not a good idea.

Every engine runs different, every cylinder on every engine inducts and exhausts (slightly) different. MamaYama' has some way to run each engine with the ECU attached so they can trim each cylinder to some target CO value. This implies that every engine/ECU are married together at the factory. Replacing either one should require matching the new engine/ECU together.

Alan

================================

More than you may want to know:

Yamaha factory has a set of headers with bungs and EGA probes installed in them. At some point during assembly the engine will be run with this set of headers installed. The exhaust will be sniffed at each of the four pipes and a 'fuel trim' value will be calculated for each cylinder. This is the number you see when you view the CO offset values. The trim value will be written to static memory in the ECU. The custom trim numbers should get the cylinder to cylinder exhaust CO levels very close. The problem is the target CO level is set for EPA standards and results in a lean engine. Lean engines tend to run hot and surge.

Because the CO offsets aren't calculated with the actual exhaust headers in place (the ones that are on the bike when you take delivery) the calculations my be off a bit but not enough to be a real problem.

CO = carbon monoxide

ECU = Electronic Control Unit a.k.a. da computer

EGA = Exhaust Gas Analyzer

bung= A hollow threaded insert swaged into a hole drilled in each of the header pipes. The EGA probe screws into the bung.

 

[BlueBullitt]

Thanks Ionbeam and its not more than I wanted to know, I just like to know what I should be looking for now that I've had my hands in it. Now after adjusting when I check the plugs do you just adjust each cylinder individually if you find a lean or rich condition? I assume adding is richening and subtracting leans. As it is the surging is gone and the bike pulls cleanly everywhere.

 

[radman]

Plugs won't tell ya **** on this bike. Too good a burn regardless of mix. Without a gas analyzer it's near impossible to get an accurate read on the numbers.