|Topic Review (Newest First)|
|Jun 14th, 2019 9:26 pm|
BIG WARNING!!! It may be important for someone considering Rapidbike for 1260. The new harness puts the device on top of the battery. The harness is not long enough to move the device under the passenger's seat (like 1200). Unfortunately, the rider seat will NOT fit in lower position with Rapidbike!!!
I tried all possible locations for the device - nothing works. The only way I see is to buy a smaller Lithium battery and stuck Rapidbike between the battery and the frame.
Not an issue for me as I use the seat in high position, just FYI.
|May 8th, 2019 6:21 pm|
Very interesting discussion and
highlighted what we should have remembered namely the operation of open vs closed loop. Thanks for that.
Now I'm really stoked to install my Rapidbike to my Multi 1260 which, I rode for the first time today.
Fast ship but the engine's power is nowhere near visceral as my Monster 1200R. No complaints as it's a different bike for a different purpose.
BTW, the Monster operates in open loop only (o2 disabled) following a Rexxer ECU flash.
|May 8th, 2019 2:25 pm|
Thanks AXSPwr! I think there is a lot of truth in what you say. RapidBike came preset for a stock exhaust. I never used it with stock, so I can't be 100% sure, but if we assume that the pre-installed maps are correct for stock (with cat) system, then looking at the adaptive values (I attached the values for both cylinders), RapidBike clearly tries to lean A/F in "low-mid RPM range/partially open throttle" with full Akra exhaust. That means the bike does actually run a bit rich in closed loop.
|May 8th, 2019 1:30 pm|
In other words, while running WOT, a fuel injected engine is running a fixed timing map read directly from the ECU. Changes to the exhaust system will have zero impact on this fuel map, so the only way a cat-less exhaust could make an engine run lean WOT would be improved harvesting from the head, combined with imperfect valve control. Not to mention, since every production vehicle uses an open-loop map that's a little bit rich for engine safety, even if those conditions existed, it still wouldn't likely result in a critically lean engine.
Partial throttle, though, is where we run into a problem without a tune, and sometimes even with one. The factory lambda sensors are programmed to operate within a range; being narrow band sensors they can't cope with oxygen levels that are way outside their normal operating condition. With a catalyzed exhaust these sensors are between the head and the catalyst; a controlled environment where such a narrow band sensor can work well. Remove the catalyst, and that sensor is open to the world. The level of oxygen detected by said sensor will increase, often outside it's operating range. If so, the ECU will throw a code, but if not, the o2 sensor will tell the engine that there is unused oxygen in the exhaust (lean), and the ECU will send more fuel to the injectors. So the common result of adding a cat-less exhaust on an untuned engine is an over-rich mixture during non-WOT operation, and a resulting net loss of power, not to mention a filthy running engine that gets poor fuel mileage. Most tuners will not resolve this issue either, because they only interact with the open-loop tables. In fact, many tuners disable the lambda sensors entirely, defaulting the closed-loop tables to under-timed settings designed to protect the engine. RapidBike is an exception in this area, at least that's their claim.
This is a complex topic and I'm certainly not suggesting everything you posted is inaccurate, I just don't think it paints a complete picture. In all likelyhood, if an owner installs an uncatalyzed exhaust on their MTS without a tune, they will experience no issue at WOT, as your dyno runs indicate. During partial throttle application, the engine will probably run rich, make less power, get poorer fuel economy, and have somewhat lower exhaust and engine temperatures due to the rich mixture. This isn't a condition likely to damage the engine, true. On the other hand, there are secondary changes that come with an uncatalyzed exhaust, such as those lower exhaust temps, that can have an opposite effect on the lambda sensors, resulting in a lean condition. How closed-loop fuel management deals with all of these parameters is basically unknowable to the layperson, so while we can say it's not normal for removing the catalyst to result in a lean condition, it's certainly not impossible either.
tl;dr: Unless you plan on running WOT all the time, you should get your race exhaust system tuned, and use a system that can work with the lambda sensors, not just disable them.
|May 8th, 2019 9:57 am|
Originally Posted by stegegjerdet View Post
|May 8th, 2019 8:28 am|
Huge differences in HP on your charts. Can't wait to experiment myself as posted in the "1260 is too smooth" thread.
|May 8th, 2019 7:33 am|
Originally Posted by DarR View Post
I still think that RapidBike worth the money. The bike runs a bit smoother, also like reduced engine braking (I got RB Racing) and additional 8HP is nice to have as well
|May 8th, 2019 7:05 am|
|May 1st, 2019 6:03 pm|
Hi, how did it go with the dominator? Seems ok? How about the noise? Needs db killer?
Originally Posted by eppy View Post
|Apr 22nd, 2019 4:02 pm|
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