Stock air fuel ratio

[djorgensen3]

Okay I have tried the search method and found several threads about air/fuel but nothing with the ballpark stock air/fuel ratio's and how a full system with no PCIII affects it. Anyone have any answers to this question? So what's a stock a/f ratio and then how would the ratio be affected on the same bike if a full system were added but no PCIII? I was told that adding a full system to a stock bike with no PCIII will richen up the fuel curve. Is this true?

 

[POSR]

I don't know what the stock A/F ratio is, but a full system will lean the mixture not richen it. A full system without a PCIII is gonna be a bike that pops a lot and really stumbles through the entire power band. Also, it may run a little hotter due to the mixture being lean. Hope that helps

 

[proud dad]

It leans the mixture up down low and in the midrange.WOT isn't really a problem.Mine would surge like crazy at low speeds with a full muzzy.Had to get a pc.Some exhaust are worse than others cause they flow better.A Yosh for example don't flow as well so alot of people run them without a pc.

 

[djorgensen3]

Well the reason I asked is, just for fun, put the stock map in my PCIII and the bike ran absolutely beautifully. It was smooth as silk all over the entire range. It ran better than the maps I've tried in it. No I haven't ahd it dyno'd yet. It's a little spendy for me right now so that has to wait. Oh and the ideas you guys posted are exactly what I though would happen. Moving more air through the system should lean everything out.

 

[GSX1300R-T]

The stock A/F ratio at idle is around 13.5 to 1. Busa(s) do not like 14 to 1 at idle or anything leaner. When I first got my 01 and started with the bolt-on mods,..........Yosh slip-ons and a K&N was my first money spent. Immediately the bike felt worse. A week later,.......I added a PCII,......and used a recommended map. The bike ran better than stock,........but the gas mileage SUCKED. A year or so later,......I purchased a wideband setup,.........and tuned the bike to it's best performance and best fuel mileage. (175 hp at the rear wheel,....and 46 mpg)

I did not use the dyno for the actual tuning,..........only to determine horsepower after the tuning.

Anytime you move more air in or out of the engine,..........you need to change the fuel curve. Good luck,.....and let us know how it goes!!!!