Idle a little jumpy.

[agentbad]

Idle is a little wonky after my latest rejetting. Those of you with pods and stock exhaust what's your jetting setup?


Current setup:
K&N 0990 pods
Pilots: 40
Mains: 110
Needle: 3 washers under both needles
Fuel screws: 2.75 turns out
Exhaust: stock

[Ghostt]

Try fine tuning the pilot screws,

Warm it up, turn 1 side pilot screw in until the rpms drop, then back out till RPM's peak (and no further)* Twist throttle...see how it reacts...tweak to taste.
Repeat on other side... test ride. You're looking for best throttle response and transition from just cracked to 1/4 throttle opening or so.*

Thats a quickie, 10 cent tutorial on setting pilot screws.**

[alex.s]

pods and stock exhaust...

[Ghostt]

I warned him about pods.

[ieathonda]

Pods would def be the factor in your idle. CV = constant velocity. With the stock airbox both carbs have evenly displaced air flowing through which would create a much more stable idle than per se pods. Pods are real sensitive to changes as well not to mention they favor higher rpm ranges.. Correct me if I'm wrong anyone but this is why I opted for a kn drop in vs a pod setup

[Ghostt]

Originally Posted by ieathonda

Pods would def be the factor in your idle. CV = constant velocity. With the stock airbox both carbs have evenly displaced air flowing through which would create a much more stable idle than per se pods. Pods are real sensitive to changes as well not to mention they favor higher rpm ranges.. Correct me if I'm wrong anyone but this is why I opted for a kn drop in vs a pod setup

Okay one more time, here's my 2¢ on the pod filters,

I would highly recommend that you DO NOT REMOVE THE AIR BOX, the carburetors on the bike are CV type and need to box to function properly, buy a K&N that fits the OEM airbox(K&N KA-2508 Kawasaki High Performance Replacement Air Filter by K&N* *Amazon.com: K&N KA-2508 Kawasaki High Performance Replacement Air Filter: Automotive* ) that's the short version.

Long boring but important answer, CV carbs stands for "constant velocity". The function of the carbs is dependent on having a calm reservoir (airbox) from which to intake air at said constant velocity. Pods draw from the turbulent, unpredictable air swirling past them as you ride, which is anything but constant. Other carbs work fine with pods. CV's = no bueno, save yourself the headaches.

Now onto jetting, first you need to tune the idle mixture screws first, I recommend 3 full turns out from bottom as a good starting point, then fine tune them afterwards. As far as buying a jet kit, I personally don't have one on either my 250, or 500 ninjas. I did got up one size on my main jets, due to they are lean from the factory, and shimmed the main needles with a small washer.

[agentbad]

Originally Posted by alex.s

pods and stock exhaust...

Haha I know. Need to get on the next Area P group buy.

Originally Posted by ieathonda

Pods would def be the factor in your idle. CV = constant velocity. With the stock airbox both carbs have evenly displaced air flowing through which would create a much more stable idle than per se pods. Pods are real sensitive to changes as well not to mention they favor higher rpm ranges.. Correct me if I'm wrong anyone but this is why I opted for a kn drop in vs a pod setup

I had a smaller K&N pod on there before that was rock solid but I crushed it trying to get it back on the carbs for millionth time. It idled great with the old one and would scream at high rpm. This one has been a little bit more finicky. If I had to do it over again I probably would go your route.

Originally Posted by Ghostt

Try fine tuning the pilot screws,

Yeah so I took a close look at everything and found one of the vacuum lines had come off when I reinstalled it last week. Also had the one of the pilot screws turned out too much. It's running a lot better now. I'm still going to take it back out and put the 112's back in since it seemed more responsive in high RPMS.

Oh yeah is there a trick getting the choke cable back on during the reinstall. Real pain the ass even with the needle nose pliers.

[ieathonda]

Choke cable is easy.. Make sure you put it into the retaining hole first inserting from the left side. Then, stretch the bent metal cable shroud to the little clip that holds it and it'll snap in. 10 seconds tops.

I dont mean to negatively bash your setup but from when I was looking up proper ways to tune pods I would try and sync the carbs and the pilot screws. I even opted to tune them further by checking exhaust temps with a laser thermometer and checking the plugs. They're finicky and will require a little more elbow grease to run well.

[Ghostt]

Originally Posted by ieathonda

Choke cable is easy.. Make sure you put it into the retaining hole first inserting from the left side. Then, stretch the bent metal cable shroud to the little clip that holds it and it'll snap in. 10 seconds tops.

I dont mean to negatively bash your setup but from when I was looking up proper ways to tune pods I would try and sync the carbs and the pilot screws. I even opted to tune them further by checking exhaust temps with a laser thermometer and checking the plugs. They're finicky and will require a little more elbow grease to run well.

The only proper way to sync carburetors is a bench sync, that's it. After that it's all tuning the carburetors themselves.

My 2¢ on syncing the carburetors @ieathonda

You can get a reasonable sync with the carbs in hand. Back the idle adjustment off to close that carb then match the second carb to it with the sync screw. You can then turn the idle adjustment up while using a thin feeler gauge (maybe .002") between the throttle plate and the throttle bore, adjust to just fit, and then check the second one and adjust to match. If you have good feel for this it will run fine once installed.*

It would do folks well to take a minute to review and understand what a sync tool does, how it works. And take another minute to look at the carb linkage and sync adjustments available to fix irregularities that might occur. It can help take some of the mystery out of this as well as stop unnecessary carb sync screwups.*

Meaning, that the carbs were right once, the butterflies were matched and it performed well, but then changed. Undecided And the problem somehow occurred in the butterfly direct shafts, or the sync screw turned or wore that pad that it rests on, or the carburetor pairing/ bridging brackets twisted in relation to each other, and enough so that the butterflies no longer operated in sync, such that performance noticeably suffered. And a fix will be accomplished by changing the butterfly position, the only thing the sync adjustment does. Hmmm. Really? Undecided*

Meanwhile, the tool measures vacuum at each individual runner. That's all it does, how it works. And vacuum is effected by a huge list of things, butterfly position being only one of them, and the only one addressed with that tool while turning those sync screws. The rest of that list includes, valve adjustment, jetting, float level, compression differences between cylinders caused by wear as well as factory CC differences in the head, intake runner, as well as flow by port variations, etc. Variations in cams, wear or factory tolerance. Then there's the potential big one, pilot jets and pilot screw mixture settings. All of those effect the vacuum and will be read by the sync tool, accurately identifyng the difference that exists, and with the only adjustment being used to "correct" the problem, move the butterfly relationship, one to the next.*

It's that clear understanding that has me of the opinion and long time practice to not touch the sync screws on a set of carbs that were right once and were never dismantled from the rack. And jet cleaning as well as float needle changing doesn't require that they be dismantled. And further, if I DID dismantle a set of carbs, I just matched the butterflies on the bench at assembly, using a feeler gauge, and then never touched them again, never gave them another thought.*

That method, properly executed, will have THAT portion of the complete equation, balanced flow to each cylinder in a multi-cylinder/ carb application due to butterfly position, satisfied entirely adequately. And in fact, it has worked for me every time I've done it on every bike (as well as individual runner/ butterfly V-8 intakes, all eight) that I've ever owned or any that I've fixed for others. And the times I fixed for others was usually after an attempt by others to sync the carbs, chasing a problem, or sometimes not even chasing a problem, but one they created wth a sync tool, chasing a problem from that list, that was never a butterfly position change problem. Those linkages are so direct and simple that they don't know how to screw themselves up. Not enough to care about.*

I'm sure this will start a lot of controversy so I won't argue it, just offering it for those who understand the whole picture that I outlined and might make good use of it. It is what I've done, on every engine I ever worked on, including blue printed racing engines as well as regular old, high mileage street stuff. I've had at least four, four cylinder bikes with over 100,000 miles that ran quite well, the whole time, and never had a carb sync performed. When they did finally get a total disassembly, this is how I set them up, on the bench. Over the years I've straightened out at least a half dozen messed up ones, probably more, and on the bench, after fixing the original problem which was fouled pilot jets.*

I only posted this because it seems like its coming up fairly often, especially with problems from a sync gone bad. One I would suggest was never a sync problem to begin with. A big or sudden change in performance is NEVER a sync problem. NEVER. Remember that. Cool If there is a problem, and you connect the gauges? YES, there will definitely be an imbalance indicated. But because that hole has a problem that is from the rest of the list. A bad plug, a plugged pilot jet, a screwed up float, a bad valve or setting, etc. Every one of them effecting the vacuum in the intake but NOT from a sudden move of a butterfly position, a sync adjustment.

[agentbad]

Carbs are synced and fuel screws adjusted with the bike fully warmed up. Yeah I figured there was an easier way to get the cable on though a pic would help.

[agentbad]

Here's what it sounds like:

Link to original page on YouTube.

She actually runs great and won't stall just a bit of a hiccup at idle. I'll fool with it more this week but hard to get off the thing when the weather is this good.

[Ghostt]

Try setting the idle at about 1,500 RPMs a little higher might help, it did mine.

[agentbad]

Originally Posted by alex.s

pods and stock exhaust...

Any slip-on options still exist for the Pregen?

@Ghostt

Yeah I tried that first but still a little bit off. I've been playing with the fuel mix screw as well. I think I have a minor exhaust leak on the right side. It seems like it's coming from the drain port. The other side has some patch work from PO.

[Ghostt]

Originally Posted by agentbad

Any slip-on options still exist for the Pregen?

@Ghostt

Yeah I tried that first but still a little bit off. I've been playing with the fuel mix screw as well. I think I have a minor exhaust leak on the right side. It seems like it's coming from the drain port. The other side has some patch work from PO.

Follow my how-to guide on idle mixture screws, as I posted above.

And what drain hole? What kind of patch work? Pictures?

As far as slip ons go, save your money, if you what loader mufflers, I have a pair of debaffeled OEM ones you can have.

Or if your handy there are a number modifications you can do to the OEM ones as well.

[agentbad]

I ended up just doing it by ear turning it in until it started to miss then backing it out 1/4 at a time. I think this is the closest I've got it so far. As for the sync I just used a sync tool but I get what you're saying with bench syncing. The bike otherwise is running great if I could only stop sneezing. Here's a pic of the bottom of the right exhaust:

[Ghostt]

As far as that leak goes, personally I'd live with it, or pick up some used ones in great shape off eBay, that what I did to replace the diy debaffled ones that came with it, it was way too loud, and sounded like crap.

When you get bored, tune the idle mixture screws per my how-to.

So is the bike running better now? Did you raise the idle up? Et ....

The picture below shows debaffelled(left) Vs OEM(right)

[agentbad]

Originally Posted by Ghostt

As far as that leak goes, personally I'd live with it, or pick up some used ones in great shape off eBay, that what I did to replace the diy debaffled ones that came with it, it was way too loud, and sounded like crap.

When you get bored, tune the idle mixture screws per my how-to.

So is the bike running better now? Did you raise the idle up? Et ....

The picture below shows debaffelled(left) Vs OEM(right)

Haha, yeah I did put the idle to 1500 with the fuel screw adjustments. Seems to be a little more consistent now. I didn't really want to fool with a new exhaust because the performance gains vs just pods is negligible.

[Ghostt]

Originally Posted by agentbad

Haha, yeah I did put the idle to 1500 with the fuel screw adjustments. Seems to be a little more consistent now. I didn't really want to fool with a new exhaust because the performance gains vs just pods is negligible.

Good call, and wise.

So other than the idle being a bit off, how is the bike under riding conditions?

[ducatiman]

ever checked your valve clearances, agent?

[agentbad]

Originally Posted by ducatiman

ever checked your valve clearances, agent?

The last adjustment was done around 8k and I am getting close to 13k now. It idled pretty well after my last carb surgery messing with the jetting but for whatever reason it's acting up now. I guess I will go ahead and pull them off again and put on the spare carb to see how it does.

[agentbad]

Okay so threw on the spare carb and switched out the mains to 112's. Top end is super sexy again but the idle issue persists. Starting to drive me a bit mad. Could it really be my valves?

[MrAtom]

I just live with my idle like this. Is that bad?

[agentbad]

Originally Posted by MrAtom

I just live with my idle like this. Is that bad?

I mean if I can't change it I will do the same.

[ducatiman]

agent-

Perhaps the audio in your vid is deceiving, but i'm hearing some heavy tapping.
I'd check them before chasing your tail.

Tuning starts at the valves...adjust and then work outward.

I'm not a fan of pods being used with CV cabs....so I'll yield to allow others to comment there.

[agentbad]

Originally Posted by ducatiman

agent-

Perhaps the audio in your vid is deceiving, but i'm hearing some heavy tapping.
I'd check them before chasing your tail.

Tuning starts at the valves...adjust and then work outward.

I'm not a fan of pods being used with CV cabs....so I'll yield to allow others to comment there.

Okay I'll go ahead and tackle that later this week. I guess I shouldn't be surprised it already needs another adjustment with my riding style.

[isuoboe]

I was going to ask the forum about the necessity of periodic carb syncing. Clearly the long quote by Ghostt (from ieathonda?) is saying NO NO NO. My bike is a 2006 Ninja 250 with 8K miles. It runs fine. The only problem I've ever had in the 3 1/2 years and 7K I've had the bike is when I didn't get the coil wire plugged back in after a valve adjustment. (That was a relief to have corrected!) I take care of "winterizing" by riding all winter, usually every week. Coldest I've ridden was 15º F. I don't go far or fast!)

One question for everyone; I'd just like to affirm that this is normal: when the bike is cold, it is pretty hard to regulate the choke so the idle is under 2,500. (I read somewhere that it shouldn't be over that.) This isn't a concern; I have no trouble warming it up by riding gently right away and have the choke off in a couple of blocks.

[Motofool]

Originally Posted by isuoboe

..........My bike is a 2006 Ninja 250 with 8K miles...........One question for everyone; I'd just like to affirm that this is normal: when the bike is cold, it is pretty hard to regulate the choke so the idle is under 2,500. (I read somewhere that it shouldn't be over that.) This isn't a concern; I have no trouble warming it up by riding gently right away and have the choke off in a couple of blocks.

That is normal.

Please, read this:
http://faq.ninja250.org/wiki/What_is..._at_startup%3F

[isuoboe]

Thanks, Motofool! I had not heard of the "gradual on" choke method. I'll have to try that. I appreciate the feedback because I don't actually know anyone with a Ninja 250!