air filter contaminated with gas

[ssmkv]

Today i removed the air filter from my ~4000 mile ninja 300 so i could do a snorkel delete (i have a yoshi slip on and no other mods.) When i removed the foam air filter, i noticed that the dirty side looked wet and oily and it turned out to be gas.

On the odd occasion when i filled up my tank i would notice later in the day that some gas has overflowed out the overflow tube but only a few drops.

Otherwise i have had no issues at all.

Any ideas how gas could have gotten there, is this something i should be worried about?

Thanks
Stephen

[Motofool]

Originally Posted by ssmkv

.........Any ideas how gas could have gotten there, is this something i should be worried about?..........

Welcome to Ninjette.org, Stephen !!!

Depending on your style of riding, it is normal that the intake valves let some mix go back into the filter box at the beginning of the compression stroke.

Wash and re-oil the foam filter....... and keep riding.

[ssmkv]

Originally Posted by Motofool

Welcome to Ninjette.org, Stephen !!!

Depending on your style of riding, it is normal that the intake valves let some mix go back into the filter box at the beginning of the compression stroke.

Wash and re-oil the foam filter....... and keep riding.

Hi Motofool,
Thanks for the warm welcome and excellent information.

I don't know what style i would be called; I rev match every downshift and ride the revs down with the throttle open slightly so that it pops and backfires (can't get enough of backfires - i drive my cars the same way) and frequently take it to WOT and 11-12k atleast once everytime i ride (which is daily to work.)

[Motofool]

Originally Posted by ssmkv

Hi Motofool,
Thanks for the warm welcome and excellent information.

I don't know what style i would be called; I rev match every downshift and ride the revs down with the throttle open slightly so that it pops and backfires (can't get enough of backfires - i drive my cars the same way) and frequently take it to WOT and 11-12k atleast once everytime i ride (which is daily to work.)

You are welcome

That explains it well.
The residual fuel on the filter may be from backfires that never ignited.

[ssmkv]

Originally Posted by Motofool

You are welcome

That explains it well.
The residual fuel on the filter may be from backfires that never ignited.

i had been thinking of replacing the air filter with a k&n insert, but some people had said that it leans the bike out. Would having a slip on yoshi and a k&n insert lean out too much or will it still be safe to daily drive. Im not really interested in getting a full exhaust or fuel controller.

in my experience with cars when you add an exhaust or intake, the ecu would overcompensate for the added air and run a little richer, are these bikes the opposite that they do not compensate for the extra air?

[Motofool]

Originally Posted by ssmkv

i had been thinking of replacing the air filter with a k&n insert, but some people had said that it leans the bike out. Would having a slip on yoshi and a k&n insert lean out too much or will it still be safe to daily drive. Im not really interested in getting a full exhaust or fuel controller.

in my experience with cars when you add an exhaust or intake, the ecu would overcompensate for the added air and run a little richer, are these bikes the opposite that they do not compensate for the extra air?

I am an ignorant regarding modifications to exhaust.

Let's call some more knowledgeable members:
@choneofakind, @alex.s, @cuong-nutz, @DaBlue1, @dcj13, @Sirref, @csmith12, @InvisiBill

[alex.s]

just a hi flo air filter in the box isnt changing a whole lot. cars use a feedback loop to correct the fuel ratio. the 300 is a simple lookup table. no "auto corrections". the slipon isnt modifying the flow of the exhaust enough to matter. the headers are what matter.


will it kill your bike? probably not. will it help your bike? probably not without chaning the fuel map. (since they come lean from the factory)

[Sirref]

Originally Posted by ssmkv

in my experience with cars when you add an exhaust or intake, the ecu would overcompensate for the added air and run a little richer, are these bikes the opposite that they do not compensate for the extra air?

Afaik the 300 doesn't automatically compensate, you would need to reflash the ecu to really get any advantage out of a full system. With a slip on there wouldn't really be any difference since the headers are where the power gains come from, as well as the increase in free flowing air.

I've never gotten gas overflow but I don't fill my tank up to the top, I fill it up to right below the little grate for the gas cap lock. Are you filling it above that?

Originally Posted by ssmkv

i had been thinking of replacing the air filter with a k&n insert, but some people had said that it leans the bike out. Would having a slip on yoshi and a k&n insert lean out too much or will it still be safe to daily drive. Im not really interested in getting a full exhaust or fuel controller.

go ahead, it won't really change much if anything though.

[DaBlue1]

See what Area P had to say about the AFR curve for the 300.

https://www.ninjette.org/forums/show...10&postcount=7

[InvisiBill]

Originally Posted by Motofool

Let's call some more knowledgeable members:
@InvisiBill

I no longer have faith in anything Hernan says.

I really don't know enough specifics about the 250/300 to add anything useful to this conversation. Based on what the others have said, it won't automatically adjust the fueling, which isn't surprising. If it really is a bit rich (it's safer to be rich than to be lean), then some small flow improvements like the K&N and exhaust might put it closer to ideal by leaning it out a tad. For best results, you'd want to retune it to match your parts, regardless of how much or little you changed (or even if it's 100% stock, according to Area P). That can get tedious and/or expensive adjusting for every little change though.