Sputtering at high RPMs

[Malicious Logic]

Does anyone else have issues where if you go WOT as in throttle pulled back as far as it'll go, it starts to get sputtery? Around 10k RPMs, it starts to sputter a little when I have the throttle all the way back but if I roll it forward just a little so it's not all the way, it goes smoothly. This is at any gear though it's mainly noticeable at 6th on the highway at WOT. I have to end up finding the sweet spot a little off WOT to get it to go. Otherwise, it sputters. I can post up a video of what I'm talking about if needed.

Is it just me or a common thing?

[edxmon]

im going to be honest and say im not even sure what you mean by "sputters"?

You mean it goes: "Poot-poot.....POOT...POOTPOOT...poot" :P, basically erradic exhaust sounds as if the engine was going to die? (like when starting a cold bike and not giving it choke)

[Motofool]

The mix may be becoming too lean at high rpms and full open throttle = more air (less restriction to flow) than fuel (more restriction to flow).
Try to find the reason for the restriction of fuel: poor tank ventilation, clogged fuel filters, clogged or too small main jets, incorrect level of fuel inside the bowls, etc.
If all that proves not to be the problem, check the gap of the spark plugs.

[cbdallas]

Start with the easiest fix first. Run some Seafoam through it and see if the issue is a dirty jet. Definitely sounds like a lean WOT condition to me.

[Malicious Logic]

Ed: I'll try to put up a video and show what I mean. Not necessarily going to die. My best guess, being someone with limited-to-no mechanical skill, is that it sounds like it's not getting enough fuel.

Hernan: That all sounds like something I'd need to take it to the dealer for.


Charlie: Is this the proper stuff?

http://www.autozone.com/autozone/acc...er=597209_0_0_

[DaBlue1]

Sounds like you may be having a rich bog at WOT.
Do you have any intake mods on the bike?
How clean is your air filter?

[cbdallas]

That's the stuff. I use it at about 1.5oz / gal. It's worked wonders with several of my old garage-rescue bikes.

[Malicious Logic]

Charlie: So I just add 1.5oz/gallon of gas and then just ride it? Is there a certain time period? Or does it just continually work as it's burning through that tank of gas?

Blue: It's got a 2 brothers slip-on but that's it as far as I know. Haven't checked my air filter. Just looked through the DIYs and it sounds like something I'll have to wait until the weekend to check if I want to keep commuting on it.

[alex.s]

sounds like jetting is definitely off... hard to say which direction without a plug check and knowing whats actually in the carbs. has it been like this as long as you have had it? is it a recent development? did you change anything before it happened? maybe let it sit for a few weeks or something? you say 2-bros slipon... are you sure its a slipon and not a full pipe? you need more information about your bike's current setup. if you dont feel confident taking apart carbs maybe find someone who is

[Malicious Logic]

Originally Posted by alex.s

sounds like jetting is definitely off... hard to say which direction without a plug check and knowing whats actually in the carbs. has it been like this as long as you have had it? is it a recent development? did you change anything before it happened? maybe let it sit for a few weeks or something? you say 2-bros slipon... are you sure its a slipon and not a full pipe? you need more information about your bike's current setup. if you dont feel confident taking apart carbs maybe find someone who is

Pretty sure it's a slip-on. It's been this way for the little over a month or so that I've owned it. I always just assumed it was supposed to do that. Definitely don't feel confident taking them apart nor do I really know anyone around here that rides/that I trust to take apart my engine.

[cbdallas]

Ride to the gas station, open the tank and pour ~7oz of Seafoam in. Then add fuel until it's about an inch from the top. Ride until it's as empty as you dare let it get.

[Malicious Logic]

Originally Posted by cbdallas

Ride to the gas station, open the tank and pour ~7oz of Seafoam in. Then add fuel until it's about an inch from the top. Ride until it's as empty as you dare let it get.

Lol, hope you don't mean in the same day. Without highway, it'd be a challenge to burn off an entire tank within one ride around town.

[alex.s]

Originally Posted by Malicious Logic

Pretty sure it's a slip-on.

pretty sure is not sure. take photos and post them here.

check the spark plug tips. white means lean, dark means rich. im willing to bet its a full pipe with no jet kit and maybe some shims under the needles

[DaBlue1]

How does the bike ride, like around 7k or so? Do you think you have enough confidence to check the air filter and see if the snorkel is in place? (takes about 10 min. or less)That may give a little indication of what mods are on your intake.

[cbdallas]

You're taking me a LITTLE too literally. You don't have to burn it all in one day. Ride like you normally do, just wait until it's nearly empty before refilling.

But when / if you can, ride it on the highway. Constant high engine speeds = more fuel being drawn through the jets = Seafoam can do its job. It'll do it's job either way, but drawing more fuel through the carb will pass more cleaning agents through the tiny jets, possibly cleaning them faster & more effectively.

[Malicious Logic]

Originally Posted by DaBlue1

How does the bike ride, like around 7k or so? Do you think you have enough confidence to check the air filter and see if the snorkel is in place? (takes about 10 min. or less)That may give a little indication of what mods are on your intake.

Think I should be able to check it if this is the correct DIY:
http://www.ninjette.org/forums/showthread.php?t=10090

I'll take some pics of the exhaust and post them up when I get off. I'll also check the air filter and take pics of that. Not sure how to check the plugs.


Charlie: Lol, alright. Sorry, just didn't know how to use it.

[THE BIG SITT]

I had the same issue. Mine was caused by a dirty air filter. Check that before you go and buy stuff...

[Felipe the Ant]

Rejet. How many miles on it? If it runs fine elsewhere I doubt you need to clean the carbs.

Take it apart and look around, it's not hard

Also look for a mouse nest in the airbox

[Malicious Logic]

Sorry, forgot my cable yesterday so couldn't upload pics. Here's some of the exhaust:









And then the air filter:






Clean side



And then...THIS is the random bolt that I found just chillin' in my air box. Surprised me a little but should've expected it after finding multiple loose items under my seat.





I tried to make a video of it yesterday but seemed to not really be as much an issue anymore. Might try again today and see if it happens. Bought the seafoam but haven't put it in yet.

[alex.s]

a clean air filter will definitely help

[DaBlue1]

Originally Posted by alex.s

a clean air filter will definitely help

+1, however a new one would be better. A stock filter is cheap to replace (Kawi recommends replacement @ 2 years) and an aftermarket one may be even better.

[Malicious Logic]

Well, I tried sea foam but the problem is still there. Also changed my oil but didn't effect it.

My MPG, as tracked by fuelly, is around 40. Not sure if this is due to riding style or related to whatever is causing the sputtering problem. Contacted my dealership of choice around here and they said it'd cost $90 per carb to clean them, but no idea if that's the issue or what. The bike is an '09 with only around 2800 miles on it. Would the carbs really need cleaning already?

I also went on a ride this past weekend with a buddy who has a WR250R and at one point, we jumped on the highway. He seemed to have way more pull in the top of his top gear than I did. I believe I was going around 75 and was tucking to counter the Oklahoma winds and next thing I know, here he comes up beside me, sitting straight up. If he hadn't let off, I'm sure he would've passed me. Now, I don't know how aerodynamic the new-gen Ninja 250 is but I'd imagine more so than the WR250. Also thought I'd read that the Ninja had more top end than the WR250 (not that the ninja has much itself).

Bottom line, really want to try to figure this out. I feel like I'm really missing out on a good chunk of my powerband because in the middle of that powerband, my bike starts sputtering.

[DaBlue1]

Originally Posted by Malicious Logic

....Well, I tried sea foam but the problem is still there. Also changed my oil but didn't effect it.


....Bottom line, really want to try to figure this out. I feel like I'm really missing out on a good chunk of my powerband because in the middle of that powerband, my bike starts sputtering.

What about changing the air filter?
When you say middle of the powerband, what rpm are you speaking off?
Is your snorkel installed?

[Malicious Logic]

Originally Posted by DaBlue1

What about changing the air filter?
When you say middle of the powerband, what rpm are you speaking off?
Is your snorkel installed?

Usually around 10k-10.5k is when it starts. Haven't changed the air filter but didn't really seem that dirty. Is the pic of mine above really a bad one? and yeah, the snorkel is still there.

[DaBlue1]

Originally Posted by Malicious Logic

.... Haven't changed the air filter but didn't really seem that dirty. Is the pic of mine above really a bad one?

It's quite normal for one side to be dirty, but both sides of your filter is filthy. The fact that it is black and not gray says its pretty clogged not to mention compressed. The pores on the stock filter are very small and can become clogged easily especially in dusty condition. In all reality your filter needs replacement. Kawi recommends replacement at 2 years. If nothing else, at least clean the one you have and see what happens.