Mechanic coined her "bike from hell". (YouTube clip)

[Ninja250grief]

My friend/mechanic has coined her "the bike from hell." This Ninja 250 has only 8,600 miles on it and was running great when I bought it for my girlfriend last December. After giving it a tuneup, it has become a nightmare that has only gotten worse with time. It seems the more work we do on her, the more temperamental she gets.

Her symptoms are: high idle, drops a cylinder, then bogs out and stalls.

At this point, she will start when COLD with full choke. If you take her off choke and give her any gas, she will bog down and stall as in the video. Afterwards, it is very hard to get her started again.

Link to original page on YouTube.

Does anyone have any ideas? We just ordered a CDI as a last ditch effort, because we can't think of anything else...


Here's what we've done so far:

1. Drained tank and filled with fresh gas.
2. New oiled air filter.
3. Oil change.
4. New NGK plugs.
5. Tested all electric and coils.
6. Pulled and cleaned carbs (weren't that dirty). Started running even worse after this.
7. Pulled and cleaned carbs AGAIN.
8. Valve adjustment. (Intake valves were tight)
9. Video = current condition

["A"]

Have you ever ran the engine up to operating temperature?

Seems like you should leave the choke on longer (not reving at 4000 rpm though), use the choke lever and have the engine idle between 2000-2500 rpm, until temp. guage until it warms up to operating temperature, then close the choke completely.

If you close the choke completely before the engine gets up to a decent temperature, of course it is going to idle at below 1k rpm and stall. These little engines are very cold blooded.. takes a little longer to warm up and get to smooth idle from a completely cold engine.

[Ninja250grief]

"A", thanks for the quick response. She still acts up after getting to temp. I just took a follow-up video to illustrate. Any other ideas?

Link to original page on YouTube.

["A"]

Have you tried adjusting the idle screw from the left (clutch) side of the bike, the black knob just above the starter?

Clockwise to raise idle rpm, counter-clockwise to lower idle rpm, adjust when engine is at operating temp., idle should be between 1500-1800 rpm.

One way to avoid engine dying on you is to keep the choke at around 2000 rpm and then turn the idle screw clockwise until idles starts to rise above 2000 rpm, close the choke all the way, then turn the idle screw counter-clockwise to lower idle rpm to desired range.

[Ninja250grief]

Oh I wish it was that simple.

[scotty]

Try adjusting the idle screw. Make sure you installed everything correctly with the carbs. If it runs worse when you cleaned the carbs, you must have missed something.

[scotty]

Never mind, "A" got to it 1st.

[alex.s]

this may be oversimlifying the issue but have you tried it with the airbox on?

edit: oh... that is the airbox... nevermind.

[Ninja250grief]

Idle screw was one of the first things tested and tuned to no luck. I've tried with and without the air filter and didn't notice much of a difference.

Any other ideas?

[cynicalkit]

Have you made any changes to the carbs or are they stock? If there is a fuel filter in the bike have you replaced it?

[Ninja250grief]

The bike is completely stock. I believe we inspected the fuel filter, but I will do a double-take. Thanks for the input, anything else come to mind?

[Ninja250grief]

Correction: I don't believe they came with fuel filters until 2000.

[crazymater91]

Just curious did you balance the carbs when you cleaned them

["A"]

If the engine can run smoothly (w/choke) at 3-4000 rpm without hicups, it's unlikely that fuel delivery (filter) is a suspect for a normal idle.

Does the engine idle at 2000 rpm with idle screw adjustment and the choke off?
or does the engine always drop to below 1k rpm once the choke is off?

[Cuongism]

How long/far did you ride it to warm it up?

["A"]

Originally Posted by Cuongism

How long/far did you ride it to warm it up?

From what I can see between the two videos, 0 miles..

[Ninja250grief]

Hey gang, I really appreciate any insight with regard to these issues. The bike is not rideable at this time so I just let it warm up in my garage.

We did not sync the carbs. Does this sound like a carb sync issue? Is this typical for the mileage?

[bdavison]

Could be the carbs not synched....but

Im guessing you got a spark plug issue.
Plugs loose, Plugs bad, Wrong spark plug wire on wrong spark plug (reversed).

Sounds to me like its not getting fire on one cylinder at the right time.

[kkim]

Originally Posted by Ninja250grief

This Ninja 250 has only 8,600 miles on it and was running great when I bought it for my girlfriend last December. After giving it a tuneup, it has become a nightmare that has only gotten worse with time.

what work was done during the "tuneup" and who did the work?

[Tony B]

Would say this definitely sounds like carbs, especially as you say it ran worse after cleaning them the first time. How did you clean them ? Possibly you shifted a tiny piece of debris into a drilling in one carb. Do you have access to someone who can ultrasonically clean them ?
Or, have you another local owner with a set of carbs you can try on the bike.
How good is the fuel flow, is the gas tank breather clear ?

["A"]

Originally Posted by "A"

If the engine can run smoothly (w/choke) at 3-4000 rpm without hicups, it's unlikely that fuel delivery (filter) is a suspect for a normal idle.

Does the engine idle at 2000 rpm with idle screw adjustment and the choke off?

or does the engine always drop to below 1k rpm once the choke is off?

Never answered my questions above..