So my bike has been acting up lately. Yes its those darn Carbs again, at least I think so. The bike seems to be hesitating at the top end it doesn't want to rev to redline. After 9k-11k it just feels forced to keep going. It also makes weird crackling pops and it almost feels like it's missing the power. It will also refuse to go past 85-90mph. I don't know why it started doing it, it seems like it just started out of the blue. The bike was running fine during the winter, not so much now that its starting to warm up.

The bike has pods, smog delete with block of plate, full exhaust, newish Iridium plugs, its Rejetted with DynoJet kit. 108 mains, stock pilots, 2 1/2 to 3 turns not sure, needles in the 3rd clip, elevation 600 or so feet. I recently did the old ninja CDI box swap but it was running fine before. I'm going to pull the plugs soon and inspect them. I also checked for vacumm leaks, resynced and cleaned the pods not to long ago.

Any suggestions? I am going to rejette again hopefully that solves my issue. Going to try 110 mains and #40 pilots, mid range seems fine might add a washer, maybe even drill the slides. It also has a erratic idle no matter what i do. If I bring it to 1500rpms it climbs to 1700rpms then settles back down. If I lower it under 1500 it iddles real low, just shy of 1k. It also doesn't turn on without full choke on.

Im just frustrated with it, when I apply the choke when the engine is somewhat warm it boggs a little , drops the rpms then starts to climb again. So its hard to tell if its lean or rich.. Once she's fully warm then the lean idle symptoms arise.. I checked all the wires on the cdi box all is well.

Any help or suggestions would be much appreciated.

How old is the gas?

What's the condition of the air filter?

The plug color will tell you if your lean or rich. Light color/white = lean, dark color/black = rich. Check the simple stuff first though, battery connections, gas, filters (pod/fuel), carb boots, petcock, vac leaks, ect, ect.

Pods are more fickle to temp changes and somewhat a pain to tune. Your gunna have to pay someone to tune it or... learn to love carbs or... loose the pods. /real-talk

Good luck!

Fuel is good always use 93 and it never has sat more than 2 weeks. I'll pull the plugs today, and inspect everything else. I'll probably end up pulling the carbs out and opening them up, make sure everything looks clean..

Save dem pennies yo, there really isn't a "need" to always run 93 all the time. In fact, you might find the bike performs better with the cheap stuff.

Save dem pennies yo, there really isn't a "need" to always run 93 all the time. In fact, you might find the bike performs better with the cheap stuff.

Once I moved to Tn from Cali I started putting 93 in everything even my Bronco and lawn mower lol.. Gas is cheap over here so I take advantage of it.:bounce:

Once I moved to Tn from Cali I started putting 93 in everything even my Bronco and lawn mower lol.. Gas is cheap over here so I take advantage of it.:bounce:

:doh:

Just a few things to consider

1. Gas- 87 octane is better than 93 for the Ninja 250. Winter gas is good for the winter, but would be better for summer it you could get it. E0 87 octane (http://pure-gas.org/index.jsp?stateprov=TN) is what you want. More octane does not necessarily equate to better running or more power. Even though you've basically changed your timing with a CDI swap, your compression did not change.
Read; The truth about winter gas (http://zhome.com/ZCMnL/PICS/winterGas/winterGas.html)
Bad Gasoline (http://motorcycleperf.com/TechTips/BadGasoline.html)
More Octane For More Power? | Mythbusters (http://www.superstreetbike.com/howtos/1108_sbkp_more_octane_for_more_power/#ixzz2Z7oCaVzC)

2. Erratic idle- Could be battery/electrical issues;
Motorcycle Battery Maintenance & Battery Charger Tips (https://www.ninjette.org/wiki/Battery)

3. Idle speed- Your Ninja is no longer stock, so the stock idle setting really does not apply to your application. Many have increased their idle speed a little to what performs best.

http://i1303.photobucket.com/albums/ag157/Krazywalle/output_zps6f7n2x3m.jpg (http://s1303.photobucket.com/user/Krazywalle/media/output_zps6f7n2x3m.jpg.html)
Here are my plugs, I kept the motor at 9-10k rpms then shut it off. Battery was fine had a full charge in under 2 minutes. I'm going to open up the carbs and see what I find..

Your plugs look OK, but your filters look a little blue. Is that FAB 1 on them?
Too much FAB 1 can cause the filter not to breath well. Ask me how I know.

Your plugs look OK, but your filters look a little blue. Is that FAB 1 on them?
Too much FAB 1 can cause the filter not to breath well. Ask me how I know.

Yeah that's the stuff... I remember once I ran it without the filters just parked and it ran well.. Started up easier with hardly no choke..

Yeah that's the stuff... I remember once I ran it without the filters just parked and it ran well.. Started up easier with hardly no choke..

It's good stuff and only takes a little bit. You have to spray a little bit and let it sit. If a spot gets to much, press the filter into that spot. I accidently sprayed too much on my filter that has much bigger pores than yours. It instantly ran like crap after putting it in. So it was re-clean, re-dry, re-oil. All good.

Save dem pennies yo, there really isn't a "need" to always run 93 all the time. In fact, you might find the bike performs better with the cheap stuff.

My bike runs better on the regular.

My bike runs better on the regular.

Everyone is trying to persuade me to use regular.. I suppose I can try a tank full once I get the old gas burnts up. The bike is in shambles right now, doing a whole bunch of random stuff as usual.
http://i1303.photobucket.com/albums/ag157/Krazywalle/output_zpse94ksqoc.jpg (http://s1303.photobucket.com/user/Krazywalle/media/output_zpse94ksqoc.jpg.html)

Try it on pure gas if you can. None of that ethanol bullsh**

Try it on pure gas if you can. None of that ethanol bullsh**

I do whenever I get a chance and I'm not lazy, its a 45 mnt journey round trip. But I've only used the 93 ethanol free not 87..

I do whenever I get a chance and I'm not lazy, its a 45 mnt journey round trip. But I've only used the 93 ethanol free not 87..

I bet you'll find the same results, if not better ones, from the 87. I don't know about you but I actually enjoy an excuse for a long ride for anything...including getting some fuel.
Also, meant to say good luck with your ride. I hope all ends up well with it and you can enjoy her.

So I inspected the bike, looked at what you guys suggested. Everything checked out OK. I decided to mess around with the jetting, the needles were left as they were 3rd notch from the top with two washers. I changed the pilots to #40s and turn the idle air mixture screws 2 1/4 turns out.

So I went to both extremes on the main jets. I took out the 108s and dropped in 110s. What I noticed was the bike was running way too hot, previous symptoms got worse, hesitation, crackling, rpms not wanting to climb after 9k rpms. I could just smell yummy gas fumes coming out the pipe. I knew it was bad to I only rode for about 3mnts. The idle still hangs a little but it got better than before, and the transition from off idle to the neddles is very smooth now, and then all hell breaks loose when I hit the main jet circuits.

So I pulled the carbs opened them up and take out the 110s and install my 104s. I was real excited and figured that would fix it. Went for a test ride and all the symptoms stated previously became worse! Except the smell of fuel. Now from 8k rpms it would just crackle and sputter and the rmps would just fight each other trying to climb up but couldn't in any gear.

The plugs with the 110s were very similar in color to the 108s. The bike revs freely in neutral with no load. There's no vacuum leaks or broken hoses. One thing I do need to do is disassembled and inspect the fuel petcock, but I've never done it. The battery had some slight corrosion on the positive terminal so I cleaned that up. I might also switch back the CDI box the OEM one. Try and rule out that possibility.

I'm confused........... .... It must be the Gremlins!

....So I inspected the bike, looked at what you guys suggested. Everything checked out OK.

Did it run better with or with out the air filter?

... I remember once I ran it without the filters just parked and it ran well.. Started up easier with hardly no choke..

Did it run better with or with out the air filter?

I haven't done that yet, thanks for the reminder. The 104s are still in there I filmed a video but my roommate ran off with the laptop so I can't upload it right now. Here's a picture of the plug
http://i1303.photobucket.com/albums/ag157/Krazywalle/output_zpsqow9asxk.jpg (http://s1303.photobucket.com/user/Krazywalle/media/output_zpsqow9asxk.jpg.html)

... Here's a picture of the plug


Looks normal.

Looks normal.

Yeah that's what I don't get, it looks like that with 110,108,104 main jets. I just came back from test ride with the filters off. Problem still persist now it starts lower in the rpm range, and you can hear it better too... I'm thinking maybe it's the CDI box..? I'm probably going to put my old one back on, and test it with the 104s and the 108 main jets... See what happens... Unless a 106 main jet will fix it? Which I don't have..

yikes! all this time consuming working messing with the carbs, and the only thing you recently changed was the CDI? Might be worth a shot , and easier, just to swap the OEM one back in and see if it corrects the problem

.... I just came back from test ride with the filters off. Problem still persist now it starts lower in the rpm range, and you can hear it better too... I'm thinking maybe it's the CDI box..? I'm probably going to put my old one back on, and test it with the 104s and the 108 main jets... See what happens... Unless a 106 main jet will fix it? Which I don't have..

"- Performance gets worse when the air filter is removed." (https://www.ninjette.org/wiki/Lean_or_Rich) is a typical lean condition
Did you re-clean the air filter?
CDI's can go bad without warning. Should be simple enough to switch back if you didn't hack up the harness too bad.:p

go up 2 pilot jet sizes, drop the clip a spot. stay at 108.

go up 2 pilot jet sizes, drop the clip a spot. stay at 108.
I have the #40s in it right now, the bike runs good with those.


"- Performance gets worse when the air filter is removed." (https://www.ninjette.org/wiki/Lean_or_Rich) is a typical lean condition
Did you re-clean the air filter?
CDI's can go bad without warning. Should be simple enough to switch back if you didn't hack up the harness too bad.:p
I need to clean the pods, but there not too dirty or clogged up. I might have to add some more wire luckily I have a whole harness to hack up. I also drained all the old fuel. I have a fresh 5 gallons of 87 ethanol free.

how did you decide 40 was right

how did you decide 40 was right

Because its idling smoothly.. What would changing the pilots do for wot? Isn't that what the main jets are for? Here's a crappy video, you can't really hear well. But towards the end you can see the idle is spot on..

aT3-QnTHnmM

.... What would changing the pilots do for wot? Isn't that what the main jets are for?

Not a lot, but they still provide fuel throughout the throttle range albeit decreased to some degree.

To me it sounds like your pilot is too low, and your main is too high

To me it sounds like your pilot is too low, and your main is too high

I have some 106s on order, I'm probably going to stick with the #40 pilots for now there definetly an improvement.. I put the 108s back in.

Here's a picture of my art work that I did to the bike. Still don't know if I like it.. That plastic dip stuff sucks.. I also broke my rear blinker I shortened it and broke the epoxy..
http://i1303.photobucket.com/albums/ag157/Krazywalle/Mobile%20Uploads/IMG_20140420_181218204_zpsa4otkmck.jpg (http://s1303.photobucket.com/user/Krazywalle/media/Mobile%20Uploads/IMG_20140420_181218204_zpsa4otkmck.jpg.html)

Did it run better with or with out the air filter?
I would test this first.

The initial problems you had make me think it may run better without the filters - which would suggest they are blocked by too much oil.

I would test this first.

The initial problems you had make me think it may run better without the filters - which would suggest they are blocked by too much oil.

I think he did a run without the filter.

....I just came back from test ride with the filters off. Problem still persist now it starts lower in the rpm range, and you can hear it better too...

Everyone is trying to persuade me to use regular.. I suppose I can try a tank full once I get the old gas burnts up. The bike is in shambles right now, doing a whole bunch of random stuff as usual.

The best choice for the Ninja is always 87 without ethanol, but if you can only get 93 without ethanol that's still better than 87 with ethanol.

Basically, the lowest octane you can get without ethanol is the best choice IMO.

I think he did a run without the filter.
Guess I missed it- thanks.

I did a test ride with no filters and the 104 mains, symptoms stayed the same, and were also more noticeable. I did not run the bike with the 108s and no filters. I did clean the pods and lightly oil them, still the same.

Bikes back together now, it's rideable but I wouldn't want to go WOT over 9,000 rpms.. It won't do over 85-90mph either. It runs like crap with 110s and it runs like crap with 104s.. With 108s, still runs like crap but less noticeable, so hopefully 106 is the lucky #s.

On the plus side I can take the carbs out under 5 mnts! With no front fairings installed..

The best choice for the Ninja is always 87 without ethanol, but if you can only get 93 without ethanol that's still better than 87 with ethanol.

Basically, the lowest octane you can get without ethanol is the best choice IMO.

I found a gas station 5 mnts from my house that sells both. Once the bike is running well I'm going to test MPGs and the dyno butt to see if it runs better on 87 or 93 eth. free. It just really bugs me to put 87 in it after years of running fine with 91oct and 93oct. Its had 89 once cause that's the highest they had and I only pumped like a gallon. And now it has like 1 gallon of 87 eth. free for testing purposes..

I found a gas station 5 mnts from my house that sells both. Once the bike is running well I'm going to test MPGs and the dyno butt to see if it runs better on 87 or 93 eth. free. It just really bugs me to put 87 in it after years of running fine with 91oct and 93oct. Its had 89 once cause that's the highest they had and I only pumped like a gallon. And now it has like 1 gallon of 87 eth. free for testing purposes..
You are lucky.

As far as octane goes - more octane doesn't mean more power. It only means more resistance to detonation - that's it.

To make the most amount of power you want the least amount of octane that you can run without detonating - you make the most power right on the edge of where detonation occurs.

For a stock engine, anything over 87 is not required and will give you less of everything - power, mileage, and economy.

Again, that's comparing non-ethanol 87 to non-ethanol 89/91/93.

I still think you are best with the lowest octane fuel that doesn't contain ethanol - sometimes that may be Premium.

So I left the carbs how they were originaly with the 108 mains, #40 pilots, I did however switch the CDI back to the OEM one. That helped a little bit. I rode the bike one cold morning it was in the mid 40s and the bike still had the symptoms. I was starting to suspect it might be the valves. They were due an adjustment in 1.3k miles so I figured might as well rule that out.

Just picked the bike up today they said one exhaust valve was loose, and they also swapped out my fairly fresh iridium plugs! I was like WTF, the service guy had said they do that with the valve adjustment. So I kindly requested my old ones.

I was able to do a small very small power wheelie shifting into second!:D. It was confirmed by my son behind me in the truck. All my symtoms went away, and I can now do triple digit speeds. After I did my 100mph celebration test run, I pulled up to the light and my temp light came on momentarily, it is 80* outside right now. I might go back to the old CDI box because it tweeked the low end circuit on the carbs so it's a little rich not horrible though. I might still install the 106 mains. But maybe later, right now I'm just glad it runs like normal again.

....I was able to do a small very small power wheelie shifting into second!:D.

A wheelie huh? :clapping:
Ever get that with 93 octane? Just sayin...

A wheelie huh? :clapping:
Ever get that with 93 octane? Just sayin...

I have but its rare, only happens when I shift hard and fast going into 2nd. So I was able to get 229 miles to a tank wich averaged out to 56mpg. That was done before the bike got fixed, so I'd assume id get better MPGs now. Highest I've gotten on 93 ETH. Free is 59mpgs...