... leaving the stock air cleaner ... but removing the cat and keeping the stock cvo slip on's ... Question is does he need a different map or a aftermarket tuneing devise ? Will the bike be to lean ....just removing the cat?
Some say the bike is too lean to start with, which is debatable in itself. The bike has EFI which is "closed loop", meaning it uses sensors in the exhaust to check whether the fuel calculations it has made were correct. If they weren't, the EFI will alter its calculations to get the combustion results in line with what it was programmed to do. The programming is often called a "map" but the better term is "calibration".
There are several places throughout the operating range where any needed corrections are saved by the EFI. These corrections become part of the basis for the fuel calculations and are used even in situations where the system is unable for the moment to check itself. Higher loads and more open throttle typically fall into this category, though engine warm-up and other conditions also benefit from the learned adjustments. Also, these correction factors are retained until either specifically cleared using equipment attached to the bike, or adjusted further for whatever reason during subsequent closed loop operation. They do not disappear on their own, even when the battery is disconnected for any amount of time.
It's important for the sensors in the exhaust to get good samples, otherwise the system can work unreliably. This is important because you don't want too much fuel (poor economy at best, possible engine damage at worst) or too little fuel (definitely can cause engine damage). Also, each of the two cylinders have slightly different requirements, so it's important to ensure each sensor samples only its cylinder's output.
This is where the "rubber meets the road" with what your friend is wanting to do. The stock system, taken as a whole, has been designed to work properly. If you alter it in any way, you stand the risk of degrading the way the EFI can check itself. Removing the catalyst from the exhaust definitely changes the way the system works.
Look at where his exhaust sensors are. There's a common chamber which currently is mostly filled with the catalyst. At the front of this chamber is where the sensors are. If he removes the catalyst from that chamber, he's going to change the way that chamber functions and he'll run the very real risk of the two sensors catching samples from the other cylinder. This is called sensor cross-sampling, or cross-talk, and if/when it occurs, it will have have a detrimental effect on the way the bike runs. Whether he changes the EFI calibration or not.
Now, a lot of folks do just what your friend is contemplating, and many of them report satisfaction. But the more astute folks often detect the effects of sensor cross-sampling.
My advice (which I've followed, myself) is to pull the stock headpipes and hang them on the shop wall. Keeping them for the possibility that some day in the future they'll need to be re-installed just for an inspection/testing session so the bike can be run another year on the roadways. Get a purpose-built exhaust system that goes right back in the same way, using the same factory heat shields, etc. Both
http://Fuelmotousa.com/ and
http://Fullsac.com/ make excellent products for this purpose. In fact, the latter has just released an economical version which may be particularly appealing to your friend.
Finally, your friend should get a tuning device with which to recalibrate his EFI so that the self-correction mechanism can do only what it was designed to do (compensate for different fuels, drifting fuel pressure, etc.) and
not attempt to accommodate part configuration changes. I recommend the currently-best available system from
http://mastertune.net/
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Topic: 2011 cvo 110 .....does my buddy need a tening device? (Read 1196 times)