carlos Posted May 12, 2017 Share Posted May 12, 2017 I cut the cut off and added a 3 inch tip. . . No remapping . No check engine . How bad is this for motor ? Should I remove and add a megaphone style exhaust ? Link to comment Share on other sites More sharing options...
koth442 Posted May 12, 2017 Share Posted May 12, 2017 Probably not awful for the motor. Clearly lacking back pressure causing a lean condition. '15 FJ09 Link to comment Share on other sites More sharing options...
duhs10 Posted May 12, 2017 Share Posted May 12, 2017 I cut the cut off and added a 3 inch tip. . . No remapping . No check engine . How bad is this for motor ? Should I remove and add a megaphone style exhaust ? What do you mean you "cut the cut off"? '15 FJ-09 w/ lots of extras... Fayetteville, GA, USA Link to comment Share on other sites More sharing options...
koth442 Posted May 13, 2017 Share Posted May 13, 2017 I read that as cut the tip off. Didn't even notice it said cut the cut hahaha '15 FJ09 Link to comment Share on other sites More sharing options...
norcal616 Posted May 13, 2017 Share Posted May 13, 2017 Cut the "cat" off and added a 3in exhaust tip is how I deciphered his question... 2012 wr250f - C-class 30+ age group 2015 fz-07- Hordpower Edition-80whp 2015 fj-09- Graves Exhaust w/Woolich tune by 2WDW @120whp Link to comment Share on other sites More sharing options...
Supporting Member texscottyd Posted May 13, 2017 Supporting Member Share Posted May 13, 2017 I'm pretty sure this question is related to an earlier thread about exhaust modifications. https://fj-09.org/thread/4741/custom-exhaust-help Depending on how radical the cat & muffler removal ended up being, I could see where some significant remapping would be in order. I bet that is LOUD! Link to comment Share on other sites More sharing options...
adjuster Posted May 14, 2017 Share Posted May 14, 2017 Still have the stock O2 sensor? Should not be too lean in closed loop. (Most of the riding around.) For best power, you'd want to reflash the ECU for more fuel on top, and to avoid possible lean running if you run around at 7k all the time. (I find most of my riding is about 3 to 5k, and that's it... Go much into the 7-9k range for too long, and you are going way too fast for city traffic, or most mountain roads around here at least for my riding style.) The popping and flames are the AIS system doing it's job. It's trying to burn off all the excess fuel in the cat that is no longer there.... So you get flames and popping on deceleration. Might have lost some low end tourqe, but might get some top end power? There is not much to find, this bike is pretty good with the stock exhaust already, and the airbox we know flows more air than the engine can pump at top RPM. Perhaps cutting the air intake sound control snorkel could reduce some pumping losses, but even stock it flows plenty of air for this engine's needs. (And the stock filter flows more than the engine can pump, so better filters only might reduce resistance to flow, but that's going to be a small gain since again, it's down low and mid range that this engine really shines, where you ride most of the time.) Link to comment Share on other sites More sharing options...
Supporting Member betoney Posted May 14, 2017 Supporting Member Share Posted May 14, 2017 I find most of my riding is about 3 to 5k, and that's it... I'm kinda speechless... But as long as you are having fun thats all that matters. I try to get up to at least 5k before shifting and never let it get at or below 4k in any gear, it just feels like it is lugging the motor to me, and thats after changing to a 15T C/S sprocket. I never get to 4th gear around town, 3rd is all you need under 45mph. Rev her out, she LOVES to pull in every gear!! ***2015 Candy Red FJ-09*** Link to comment Share on other sites More sharing options...
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