Observation and a question about PCIII maps

[Red05]

I noticed in looking at the various PCIII maps that the majority of the boxes, arranged in throttle opening/RPM range, have negative numbers, particularly in the middle areas. As these charts are called fuel tables, I take it the map leans the mixture (less fuel) in these throttle opening/RPM ranges. Replacing the exhaust with a free flowing high performance unit I would think would increase the amount of air going through the engine. Wouldn't more fuel (enrichening) then be necessary to maintain proper mixture? I realize I've made some assumptions here and I may be way off base.

 

[clrwtrbusa]

Busa's tend to run rich with the factory settings. Changing the air filter will lean the bike out some, but changing just the exhaust will still only flow the same air as the stock pipes. Although there are maps for specific setups, the best map is one set up for your bike. We tried the same map on 2 bikes with same mods. One ran good and the other had flat spots in the powerband.

 

[Red05]

Thanks, clrwtrbusa. Yamahas, at least the FZ1 & FJR I've owned, both ran fairly lean stock. I guess I assumed the Busa would be the same way. I've got the HMF dual muffler set-up on my bike, and it runs very well with the Akrapovic full system map. That said, your comment about each bike being different makes me want to eventually take it to a tuner and have it custom mapped.

 

[clrwtrbusa]

If you are thinking about getting it mapped, decide on which air filter you will want to run and get it before hand. That way your bike is set up the way you want it. Lots of people pay for the tuning and then change stuff right away, me included



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[Red05]

Good point, clrwtr. I'll do that beforehand.