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Discussion Starter #1
Okay so I have removed a few exhausts in the past and usually after adding a slip on or removing the CAT the bike likes to pop or even flame on Deceleration but on the 400 I have removed my CAT and even added a slip on and im getting no flame or popping? Does the bike come from he factory a little rich? it would be the first bike I have ever ridden that does lol now here is why im thinking the bike is running lean and not rich, Im starting to feel some more heath coming from the bike and I usally find thats a sign of a lean mixture, bike feels much more responsive and runs great with no popping or back firing so im a little confused, just would like some other people opinions and history on similar issues ect
 

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It's been my experience too that with adding aftermarket slip ons you can induce a bit of popping on the over run.
Some say that the popping is already there with the OEM system but you just cant hear it because of the CAT and the ridiculously high levels of baffling from stock now.

Also PAIR valve systems are known for inducing popping/detonation with the fresh air it adds to the mix. Have you removed yours yet?

Looking at the colour of your tail pipe will generally give you an indication of how lean your running
 

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Discussion Starter #3
It's been my experience too that with adding aftermarket slip ons you can induce a bit of popping on the over run.
Some say that the popping is already there with the OEM system but you just cant hear it because of the CAT and the ridiculously high levels of baffling from stock now.

Also PAIR valve systems are known for inducing popping/detonation with the fresh air it adds to the mix. Have you removed yours yet?

Looking at the colour of your tail pipe will generally give you an indication of how lean your running
thats been the case with me as well, im using the same slip on I was using on my 300, on the 300 it would pop like crazy yet on the 400 it doesnt pop at all? par system is still in there as well
 

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thats been the case with me as well, im using the same slip on I was using on my 300, on the 300 it would pop like crazy yet on the 400 it doesnt pop at all? par system is still in there as well
Just a slip on on my 400, I get a bit of crackling and popping on mine.
 

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May I ask, what is lean or rich referring to exactly?
Edit: And why does it make it pop or not (the pop / fire i get).
 

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May I ask, what is lean or rich referring to exactly?
Edit: And why does it make it pop or not (the pop / fire i get).
It's referring to the air/fuel ratio (AFR) of the mix coming into the combustion chamber. Generally somewhere around 13 parts air to one part fuel.
So a mixture that deviates from this towards more fuel is referred to as being 'rich', and a mixture with an increased number of air parts is referred to as being 'lean'.

The popping is the detonation of unburnt (left over) fuel after the combustion process has taken place. Somewhere inside the exhaust port or possibly the header pipe even.
 

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Aw!! Okay, I think i read our bikes are 11:5:1?? OHHH so a lower first number refers to less air/fuel. Sorry i could probably just google this. So the original poster is trying to accomplish a lower air / fuel ratio, meaning more fuel and less air, right in order to POP IT LIKE ITS HOT?
 

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Discussion Starter #8
Aw!! Okay, I think i read our bikes are 11:5:1?? OHHH so a lower first number refers to less air/fuel. Sorry i could probably just google this. So the original poster is trying to accomplish a lower air / fuel ratio, meaning more fuel and less air, right in order to POP IT LIKE ITS HOT?
lol no you dont want after fire or popping as it likely results from a unbalanced AFR. Im wondering why my bike isnt after firing and or popping after having allowed so much more air into the engine by adding a full system and slip on. So popping or after fire usally means lean condition yet im getting none of that though the exhaust does feel hotter which does indicate a lean condition as usually a rich condition means the bike has more fuel and runs cooler. most bikes come lean from the factory to pass euro4 laws and emissions so thats why im very confused
 

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Aw!! Okay, I think i read our bikes are 11:5:1?? OHHH so a lower first number refers to less air/fuel. Sorry i could probably just google this. So the original poster is trying to accomplish a lower air / fuel ratio, meaning more fuel and less air, right in order to POP IT LIKE ITS HOT?
Your getting confused with the compression ratio. The AFR is not a listed spec and it changes at different RPM, it's not a constant.
Yes, probably best you google this stuff if interested.
 

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Discussion Starter #10
Your getting confused with the compression ratio. The AFR is not a listed spec and it changes at different RPM, it's not a constant.
Yes, probably best you google this stuff if interested.
Yep I think it changes every 100rpm, example your bike can feel nice and responsive all the way upto 4000rpm but as soon as you hit 4000rpm it has a slight jerk or even if really bad a back fire while accelerating tho as soon as you pass over 4000rpm lets say 4300rpm the bike feels great again it likely means your AFR is incorrect in that rpm range. usually the lower RPM's are where people have problems aka it runs lean due to the company selling the bikes lean in the lower rpm range and then people adding slip ons and full systems which only makes the mixture even leaner, they come lean from the factory to pass emission laws ect hence why the top of the RPM range is usally rich so when you add a full system you usally feel the bike more sluggish down low and more power on the top. for this a dyno is your best bet but usally just flashing the ECU to a custom map will fix most problems, you can download akro and yoshi maps from the dyno jet website right now :)
 

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Yep I think it changes every 100rpm, example your bike can feel nice and responsive all the way upto 4000rpm but as soon as you hit 4000rpm it has a slight jerk or even if really bad a back fire while accelerating tho as soon as you pass over 4000rpm lets say 4300rpm the bike feels great again it likely means your AFR is incorrect in that rpm range. usually the lower RPM's are where people have problems aka it runs lean due to the company selling the bikes lean in the lower rpm range and then people adding slip ons and full systems which only makes the mixture even leaner, they come lean from the factory to pass emission laws ect hence why the top of the RPM range is usally rich so when you add a full system you usally feel the bike more sluggish down low and more power on the top. for this a dyno is your best bet but usally just flashing the ECU to a custom map will fix most problems, you can download akro and yoshi maps from the dyno jet website right now :)
Good info mate. The only thing that I would add is that at higher RPM's the system goes back to Open Loop operation, running off the fuel maps stored in the ECU rather than measuring data from the O2 sensor and correcting to suit. Generally correcting to a lean AFR, like you said, to pass emission tests.
 

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Discussion Starter #12
Okay I have been in talks with a few Dyno companies down in sydney that work closely with woolich racing ect and all have said the ninja 400 down in Sydney come lean stock :/ they said most have been lean with the exception of a couple. so looks like adding a full system will definitely require a fuel map adjustment. ARHHH more money to throw away. will be flashing using the Akro fuel map as I usally find the akro maps usally add more fuel in than the yoshi system and alot more people use akro system so theres a lot more data and testing going in on them, unless kiwi does his tune first and sends me his map ;)
 

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...will be flashing using the Akro fuel map as I usally find the akro maps usally add more fuel in than the yoshi system and alot more people use akro system so theres a lot more data and testing going in on them, unless kiwi does his tune first and sends me his map ;)
Lol, Wont be till the spring mate, I ain't doing the 1100km round trip to the guys shop in winter. The joys of living in remote areas eh.
Remind me nearer the time about the map if u still want.
 

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Discussion Starter #14
Lol, Wont be till the spring mate, I ain't doing the 1100km round trip to the guys shop in winter. The joys of living in remote areas eh.
Remind me nearer the time about the map if u still want.
yeh thats fine mate, I wish these ECU flash kits could work on multiple ECU but you have to register your ECU then u can only flash that single ECU :/ that way we could all just share 1 kit and all have bikes running much better, for now ill flash the akro map, either way will be alot better than stock
 

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It's been my experience too that with adding aftermarket slip ons you can induce a bit of popping on the over run.
Some say that the popping is already there with the OEM system but you just cant hear it because of the CAT and the ridiculously high levels of baffling from stock now.

Also PAIR valve systems are known for inducing popping/detonation with the fresh air it adds to the mix. Have you removed yours yet?

Looking at the colour of your tail pipe will generally give you an indication of how lean your running
can i remove the PAIR system with just my slipon?
 
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