Ninja 400 Riders Forum banner

Running Lean or Rich?

10K views 14 replies 5 participants last post by  10gunz 
#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
 
#2 ·
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
 
#6 ·
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.
 
#7 ·
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?
 
#8 ·
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
 
#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 ;)
 
#13 ·
...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.
 
#14 ·
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
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top