Hello one and all,
I've recently had a TwoBros Juicebox Pro fitted to my Ninja 650R, should the O2 sensor still be connected to the exhaust bung or would it override the Juicebox? I'm having an Arrow slip-on fitted tomorrow so wondering whether I should ask them to not connect the O2 sensor?
Thanks in advance
Ive never used the Juice Box Pro but imagine it should come with pretty clear installation instructions? Though if the Juice Box is designed for the US model Ninja 650R that bike does not have an O2 sensor, in which case the instructions might not be correct for your bike...Originally Posted by skybluestu
I had the old Juice Box on my old ER6n and it did NOT require the removal of the exhaust sensor. I'm tempted to guess the same if true of the Juice Box Pro.
The Large Print Giveth, and the Small Print Taketh Away
How did the install go? Typically these "piggyback" FI modules work best with the stock O2 sensor removed/disconnected. If it is not, then the ECU will try to go into closed-loop mode at certain RPM/throttle openings and try to adjust the mix to its pre-programmed O2 % setpoint. Effectively nixing out your post-ECU map adjustment in the closed-loop ranges.
I know my PowerCommander III for the FJR and the PCV for the FZ1 both came with an O2 sensor "fake out" plug so that the bike did not throw a CEL (Check Engine Light) error. So I don't think there is any danger in removing the O2 sensor as the ECU will just default into open loop and let the Juicebox do its thing without interference.
After reading the advice from Tony and also on a few other forums I decided to keep the O2 sensor connected when I had the Arrow pipe installed. It does seem more responsive with a smoother flow all through the rev range but there is some slight popping/backfiring on deceleration, I thought the juicebox was supposed to prevent that?
***EDIT*** Just read about backfiring during deceleration and many bikes with the stock pipe removed do this and is nothing to worry about.
True that it won't hurt anything, but it sure is irritating. The backfire is due to a few different things and a Juicebox or Powercommander alone typically will not fix it. Some people claim to have reduced it by adding fuel in the zero throttle column but I have my doubts. Mainly because the main culprit for the backfire is programmed into the factory ECU as an emissions requirement for cutting the fuel under certain throttle positions and RPM. This is a US Federal EPA and EU requirement and no modern ECU controlled bike is exempt. Adding fuel to a piggyback module will not work in this case because the fuel injection is TURNED OFF at the source. You could add 100% extra fuel to the map and it would do nothing.
What happens is the fuel is cut at say 6000 RPM at zero throttle to reduce emissions and then the ECU turns it back on at 4500 RPM and "re-wets" the hot and dry combustion chambers with fuel. That's where you get the loud BANG on decel. The other way backfire or burbling happens is from the AIS (air injection system) that is supposed to assist in burning unburned fuel in the exhaust ports and assisting the catalyst in being more efficient. Not sure about the Ninja, but most bikes can have the system plugged at the airbox or have the entire system stripped off by installing AIS block-off plates on the heads or valve cover.
Yes, what Feejer says is accurate. A properly tuned fuel injection module will help reduce, but will not eliminate after-fire.
Plugging or removing the PAIR valve (also called Clean Air valve) will also help reduce afterfire.
The PAIR valve is an emissions device designed to introduce air from the airbox into the exhaust manifold to increase the efficiency of the catalytic converter. It has no effect on performance.
If stock exhaust has been replaced with aftermarket there is no longer a catalytic converter so the PAIR valve no longer serves any purpose. It will continue to put air into the exhaust which will increase the amount of afterfire. Afterfire will not damage engine or exhaust. (Well, I have seen some glass pack mufflers lose their packing as a result of excessive afterfire, but that's not an issue for most pipes).
The pair valve is the same on Kawasaki EX650 (ER6n/Ninja 650R) and KLE650 Versys:
PAIR valve plugged with silicone caps.
Airbox breather outlet plugged.
Exhaust intake plugged.
A view from the airbox to the PAIR valve after plugging both and removing the hose.
Ride On!
Tony
The Large Print Giveth, and the Small Print Taketh Away
Thanks guys, much appreciated!
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