2009 Ninja 250 running bad - Need urgent help!!

[Bones85]

I was doing about 50-60mph in 6th gear when all of a sudden the bike started sounding really strange. The exhaust note got much deeper and I felt a loss of power as well. I pulled over to the shoulder and tried to figure out what was wrong but eventually had the bike towed home because it wouldn't run properly.

I've noticed a few things so far:

1) The bike will barely idle now, even with the choke on. It also seems to be backfiring when I rev the bike up a little.
2) The bike won't really rev up. I twisted the throttle and there was hardly any response.

I had just refueled and rode about 20 miles when this happened. Could a bad batch of gas damaged something? Or could the spark plugs be fouled up? I just changed them a few months ago.

I can take a video if that will help.

Thanks.

[lgk]

video would help.

how many miles on the bike?
when was the last service?

[alex.s]

air intake is blocked. check contents of tail.

[bdavison]

or the exhaust flange came loose on one or both sides.

[lgk]

since everybody else is guessing, i'll pick the vacuum hose popped off or is leaking

[Bones85]

One of the spark plug ignition wires was loose so I guess the bike was running with only one spark plug?

[Motofool]

Originally Posted by Bones85

One of the spark plug ignition wires was loose so I guess the bike was running with only one spark plug?

That could explain the poor mileage your bike has been doing, Joe.

Similar thing happens when some of the plugs going into the coils get loose after a valve service.

A cylinder feels cold, while the other feels normally hot.

[alex.s]

i just spit on the header and see which one doesn't fizz

[Motofool]

Do not discard advice of post #3 above.

Did you check it?

[Bones85]

I'm going to go ahead and replace both spark plugs right now. I'm hoping my gas mileage will be better now too. Last time I only got 48mpg even after riding conservatively on the highway for 123 miles.

How do I check the air intake?

[alex.s]

48mpg is great. i only get about 35.

to check intake snorkel, remove the rear seat, look down the tail. the intake is on the right hand (throttle hand) side at the bottom of the tail... theres usualyl manuals and stuff in there that can slide down and block the intake.

[Motofool]

Originally Posted by alex.s

48mpg is great. i only get about 35.......

You should see a mechanic.............quick ...........

[alex.s]

:P

riding style may vary.

[Bones85]

48mpg is bad considering I accelerated like a granny and shifted into 6th gear by 40-45mph and 99% of the 123 miles were on the highway.

I replaced both of the spark plugs and the bike seems to be running fine now. I'm worried about the spark plug ignition wires coming loose again though. They seem to be seated properly but I hope I don't have an issue with them after riding a few thousand miles.

[TS250]

Originally Posted by alex.s

48mpg is great. i only get about 35.

to check intake snorkel, remove the rear seat, look down the tail. the intake is on the right hand (throttle hand) side at the bottom of the tail... theres usualyl manuals and stuff in there that can slide down and block the intake.

I ride quite hard and have bigger rear rim and tire, and aftermarket pipe. I get 55 rain or shine

[alex.s]

Originally Posted by TS250

I ride quite hard and have bigger rear rim and tire, and aftermarket pipe. I get 55 rain or shine

hows your tuning setup

[TS250]

Originally Posted by alex.s

hows your tuning setup

Just a K&N air filter, no jetting.

[alex.s]

let me know how that mileage goes when you rejet for optimal power.