Bike not wanting to rev past ~5k while driving

[FvnnyL3tt3r1ng]

So I'm just driving along just fine and all of a sudden my bike gets this bogged down sound and it won't go past 5k rpms in any gear, as if the rev limiter is kicking in. I did get it up to 7k on a long straightaway but very briefly. I looked at the spark plugs and they look fine. I put a new fuel filter on tonight and rode it (after the problem started; old filter was warped), same problem (slightly better). I synced the carbs because I was planning on that anyways as well.....

The bike DOES however, redline in neutral! Not sure if it does with the clutch pulled in while in gear though........ The oil was topped off before I rode and I got a good 40 miles in before the problem started happening..... any ideas?

[csmith12]

What else has changed? New exhaust? Check airbox and filter. Did the bike sit for a while?

[FvnnyL3tt3r1ng]

Originally Posted by csmith12

What else has changed? New exhaust? Check airbox and filter. Did the bike sit for a while?

Nothing really. I drive this bike every day.

[csmith12]

Bad tank of gas?

[Jiggles]

Did you check your air filter?

[93etgocart]

my cbr did this when the rings blew out. Not saying thats it but just an experience

[FvnnyL3tt3r1ng]

Originally Posted by Jiggles

Did you check your air filter?

I didn't. I have a K&N air filter I don't remember how tight of a fit it was....

[Jiggles]

Check it, see if its wet, dirty, or has engine oil in the airbox

[FvnnyL3tt3r1ng]

Originally Posted by csmith12

Bad tank of gas?

Never had a bad tank of gas in my life so I wouldn't know what that's like. I just don't get why I can redline in neutral but not in gear while driving........

[Jiggles]

If you were running really rich (clogged air filter) that would be one reason

[Alex]

If it sounds funny, and suddenly has half power, it sure seems like you're running on only one cylinder.

[FvnnyL3tt3r1ng]

Originally Posted by Alex

If it sounds funny, and suddenly has half power, it sure seems like you're running on only one cylinder.

I think so too but why

[csmith12]

Originally Posted by csmith12

Check airbox and filter

Mice build a nest in the airbox? Sounds like a starvation problem, gas or air. My vote is on gas.

[FvnnyL3tt3r1ng]

Checked air filter and it looked fine.

Is it possible that something in the fuel line clogged the carbs?? It happened while I was driving....

[GeorgeRYoung]

Something clogged up one or both?

[Panda]

Plugged up snorkel?

[alex.s]

it sounds like only one of your main jets is clogged.

run it then mist the headers with water. one will boil and evaporate the water instantly while the other will take considerably longer. the one that is cooler is the one you want to look at.

[FvnnyL3tt3r1ng]

I take it now would be a good time to learn how to rebuild or at least clean my carbs since the bike is about 12 years old and I'm almost certain has never been cleaned before............

[FvnnyL3tt3r1ng]

Originally Posted by FvnnyL3tt3r1ng

I take it now would be a good time to learn how to rebuild or at least clean my carbs since the bike is about 12 years old and I'm almost certain has never been cleaned before............

Glad I chopped my airbox last week.

[FvnnyL3tt3r1ng]

When doing the carb cleaning, are there kits I can buy with nice replacement parts such as gaskets/screws/needles/washers? What are the minimum tools needed to do this job? I already have carb cleaner but I'd be up for replacing any o-rings/gaskets if they're cheap enough...

[DaBlue1]

Originally Posted by FvnnyL3tt3r1ng

Glad I chopped my airbox last week.

Did you by chance remove the carb boots at all? If so, you may want to check them for leaks. Too much air can also cause the symptoms you have.

http://www.ninjette.org/wiki/Troubleshooting_Guide

Poor Running at Low Speed:

Fuel/air mixture incorrect:
Carburetor holder loose
Air cleaner duct loose

[FvnnyL3tt3r1ng]

Originally Posted by DaBlue1

Did you by chance remove the carb boots at all? If so, you may want to check them for leaks. Too much air can also cause the symptoms you have.

http://www.ninjette.org/wiki/Troubleshooting_Guide

Poor Running at Low Speed:

Fuel/air mixture incorrect:
Carburetor holder loose
Air cleaner duct loose

Good point! I have been noticing a little lag in the past month or so though come to think of it because I remember saying to myself that I'd have to learn how to clean the carbs soon.

It still gets me that it won't go about ~5k rpms even in first gear though....but fine in neutral/clutch in

[Motofool]

Originally Posted by FvnnyL3tt3r1ng

.....It still gets me that it won't go about ~5k rpms even in first gear though....but fine in neutral/clutch in

Because the engine has lost the torque now.

The resistance of the tires and mass of the bike is enough to move the rpms' back to the zone of better torque (lower rpms').

Did you check if one cylinder is dead (cold)?

Wasn't this the bike having spark only on one side?

[FvnnyL3tt3r1ng]

Originally Posted by Motofool

Because the engine has lost the torque now.

The resistance of the tires and mass of the bike is enough to move the rpms' back to the zone of better torque (lower rpms').

Did you check if one cylinder is dead (cold)?

Wasn't this the bike having spark only on one side?

No actually I forgot to try the spray-water-on-the-header method someone recommended but the spark plugs looked fine and idk if this says anything but both the exhausts out of the pipes are coming out (warm). I'm not positive but as I was just removing the air box I think one side of the carbs intake may have been loose...... The airbox also had a little oil on it at the bottom. So the bike puts out the same amount of torque per RPM?

[FvnnyL3tt3r1ng]

Originally Posted by Motofool

Wasn't this the bike having spark only on one side?

That wasn't my bike it was member "249cc"

[choneofakind]

Check the boots that connect the carbs to the airbox. Are those spring clamps on there good and snug? Are they leaking air? Did they come off completely?

This sounds like the same thing that happened to a friend's bike. The airbox popped off and it would suck under WOT, but we could baby it up to redline with small throttle openings.

and trust me, your bike with make it to darn near redline on one cylinder. It just takes a while. Been there, done that

[FrugalNinja250]

Check electrical connections to the coils. Wiggle the connectors while motor is running, any change and you found the problem.

[FvnnyL3tt3r1ng]

I'm looking through my ninja haynes manual, and I see this: "Also make sure that the end of the carburetor vent tube is not placed near the air intake. This will cause fuel starvation, resulting in poor performance above 3,500 rpm and a maximum engine speed of 5,000 rpm." (P. 4-5)

Source: Haynes Service & Repair Manual Kawasaki Ninja 250, Haynes North America Inc, Newberry Park, CA.

[FvnnyL3tt3r1ng]

Do I really have to spend $60 to rebuild my carbs??? How in the world is there nothing cheaper

http://www.ebay.com/itm/92-05-KAWASA...f74a05&vxp=mtr

[choneofakind]

For $60, just buy a entire new petcock assembly. The rebuild kit is normally ~$30

[FvnnyL3tt3r1ng]

Originally Posted by choneofakind

For $60, just buy a entire new petcock assembly. The rebuild kit is normally ~$30

I don't follow? Are you recommending I buy a petcock assembly to get more bang for my buck?

[choneofakind]

Oh, wow I somehow got it in my head that you wanted to rebuild the petcock and I was suggesting you just replace the petcock instead of repairing it.

I'm sorry about any confusion I caused.

[FvnnyL3tt3r1ng]

Originally Posted by choneofakind

Oh, wow I somehow got it in my head that you wanted to rebuild the petcock and I was suggesting you just replace the petcock instead of repairing it.

I'm sorry about any confusion I caused.

Np.

Is it possible to POD the bike with stock exhaust and jets or do I have to rejet?

[choneofakind]

Stock exhaust, yes. Stock jets, no. You'll likely be running a 108 or 110 main jet with a pod intake and stock exhaust.

If I were you, I'd get your bike figured out and fixed before you start making changes. It's easier not to introduce more variable into the mix when you're fixing things.

[FvnnyL3tt3r1ng]

Originally Posted by choneofakind

Stock exhaust, yes. Stock jets, no. You'll likely be running a 108 or 110 main jet with a pod intake and stock exhaust.

If I were you, I'd get your bike figured out and fixed before you start making changes. It's easier not to introduce more variable into the mix when you're fixing things.

Just got done with the valve clearance for the first time. Glad it's all over and done; I will definitely be buying the kawi tool to do it next time! Hope I did it right I set them all to the looser end of the spec... They were all tight so it needed to be done anyway. Probably the first the bike has ever seen @ 12.5k miles.

[choneofakind]

Good! That should help a lot if it's the first one that's been done. Mine always starts better after a valve job.

[FvnnyL3tt3r1ng]

Took carbs apart tonight and cleaned them. Looks like there is a tear on the outer rim of one of the diaphrams but I put it back together the best I could and hopefully it will work.

My decelleration cable seems it may be broken as there is no pullback from it at all......hopefully this isn't the case. It can be pulled a couple of inches without retracting any.... I will try the adjustment procedure and hope for the best for that as well.

[choneofakind]

Decel cable should be cheap to replace.

There's a DIY from theduck on how to fix those diaphragms. I think that's what's causing your issues. You could try gorilla glue or a bicycle tube repair kit. I'll look around for that DIY for you.

EDIT: I found the DIY for you. http://www.kawiforums.com/ninja-250r...patch-diy.html

[FvnnyL3tt3r1ng]

Ok thanks! I'll try this out if my bike still messes up. I'm about to crank it up in a minute actually to sync the carbs but I have to throw a new chain on before I can ride it.

[FrugalNinja250]

Fix the torn diaphragm first, it will change everything else. Remember, known problems are the low-hanging fruit and you want to get them *all* out of the way before proceeding to the more complex issues.