Dropped Ninja 250 at low speed and now idles extremely high

[Truant]

Half an hour ago I was riding my 07 Ninja 250 up a slight incline to then make a U-Turn. I dropped my speed way too low and I felt the bike starting to tip over to its left. I couldn't stop it in time, but managed to slow its fall enough to at least save it from any external damage. It stalled out and I quickly hit the kill-switch.

When I started her up again, suddenly she was running at around 5-7k revs while idling. Usually its at around 1-2k, and that's when it's warmed up. Please correct me if I'm wrong here, but I decided to then ride it around, thinking that the fuel/air mixture was too rich in fuel, which would hopefully relieve the carbs of the extra fuel.

Instead, my ninjette's been sounding like it's about to fkin explode...cars, pedestrians, and bicyclists all avoid me like I'm about to catch on fire. Sure, nobody is going to hit me, but now I'm afraid that something is seriously wrong. Just through engaging the friction zone at 1st gear I'm buzzing around at 20mph - with zero throttle input.

Somebody please help me out. I'm rather not go to a mechanic if I don't have to.

[Motofool]

Originally Posted by Truant

........... Somebody please help me out. I'm rather not go to a mechanic if I don't have to.

The sudden change may have to do with the limit position of the (2) butterfly valves inside the carburetors.
It seems that the knob that regulates that limit or top has been affected when falling on the left.

If that is not the problem, then the throttle cables are the next thing to check.
They should have a minimum but noticeable slack when the throttle control is released.

The third thing to check is that throttle grip, which could be preventing the free return of the throttle due to some axial force exerted during the mishap.

The less probable but still fourth and last thing to check is the cable that pulls the choke open; that one needs to give some slack to the plunge in the carburetor, so it completely closes any by-pass of fuel.

Please, see these:
http://faq.ninja250.org/wiki/What_is...I_adjust_it%3F

http://faq.ninja250.org/wiki/Adjusti...hrottle_cables

http://faq.ninja250.org/wiki/Throttl...is/re-assembly

[Truant]

Originally Posted by Motofool

The sudden change has to do with the limit position of the (2) butterfly valves inside the carburetors.
It seems that the knob that regulated that top has been affected when falling on the left.

If that is not the problem, then the throttle cables are the next thing to check.
They should have a minimum but noticeable slack when the throttle control is released.

The third thing to check is that throttle grip, which could preventing free return of the throttle do to some axial force exerted during the mishap.

The less probable but still fourth and last thing to check is the cable that pulls the choke open; that one needs to give some slack to the plunge in the carburetor, so it completely closes any by-pass of fuel.

Please, see these:
http://faq.ninja250.org/wiki/What_is...I_adjust_it%3F

http://faq.ninja250.org/wiki/Adjusti...hrottle_cables

http://faq.ninja250.org/wiki/Throttl...is/re-assembly

Thank you!!! I'm gonna try these asap and see how it goes.

[f0r54ken]

Just throwing out another simple one, The Choke on your left handle bar could have gotten damaged. How does your bike behave when you put it up and down?

About the throttle cable, That's a good thing to check. If you watch the right side of your bike with it turned off and twist the accelerator bar you'll notice The right side of the carb will lift a little pulley. That pulley has a bottom point where the two brass points should clash together stopping it from dropping anymore. You should make sure those two points are reaching. if they aren't then your bike will be above it's desired idle point.

(best pic I could find) it's on the left of this photo. right side of your bike.


And yeah I know what you mean about that embarrassing rpm. Anytime i'm on a freeway My rpm's are up there at 7-8k and I feel like a total boner. Lol I hope you find out the problem

[Truant]

First off - thanks for the help guys!

I checked my twist grip and my throttle cables - no issues there. So I started her up and just kept dialing back the idle screw until I had the idle revs around 1700. It runs better than ever!

However, I've now noticed there's a bit of rpm fluctuation when I'm idling. The needle vibrates between 1600-1800 rpm. Is this ok? I can't say if I've always had this vibration but otherwise everything seems to be in pretty good order.

[f0r54ken]

Originally Posted by Truant

First off - thanks for the help guys!

I checked my twist grip and my throttle cables - no issues there. So I started her up and just kept dialing back the idle screw until I had the idle revs around 1700. It runs better than ever!

However, I've now noticed there's a bit of rpm fluctuation when I'm idling. The needle vibrates between 1600-1800 rpm. Is this ok? I can't say if I've always had this vibration but otherwise everything seems to be in pretty good order.

Cool! Maybe the idle screw got shoved into it's port on the drop...

You're lucky it Stays that stable. Well still keep a close eye on it for a little bit. Check your oil and coolant make sure nothing broke between those guys Your lights too, Cracks in the plastics, the usual.

Otherwise make sure you send a thankful prayer to the motorcycle gods.

[Motofool]

Originally Posted by Truant

First off - thanks for the help guys!
.......However, I've now noticed there's a bit of rpm fluctuation when I'm idling. The needle vibrates between 1600-1800 rpm. Is this ok? I can't say if I've always had this vibration but otherwise everything seems to be in pretty good order.

You are welcome

That fluctuation could be induced by a vacuum leak, either in one of the rubber boots connecting engine and carburetors or in one of the vacuum tubes.

Spraying some WD-40 or started fluid over those areas is the usual way to pinpoint the leak.
The rpm's suddenly increase when the fluid is sucked into the intake via that vacuum leak.

Out of adjustment valves can also cause some fluctuation.

The actual idle rpm's should be set after the engine is hot.

[Khan]

As far as the fluctuations are concerned, does the bike seem to lose power for a fraction of a second ? If yes, its probably the carbs which need to be cleaned bc the fuel might have entered when the bike fell on the side

[Truant]

Originally Posted by Khan

As far as the fluctuations are concerned, does the bike seem to lose power for a fraction of a second ? If yes, its probably the carbs which need to be cleaned bc the fuel might have entered when the bike fell on the side

Actually, opening the throttle is now more responsive than before I adjusted the valves. However, closing the throttle now completely dumps all power. I find that I can't coast as well as I used to - the bike jerks around more than before. Is this normal?

Also I've done a bit of reading into valve adjustment/carb cleaning and it looks a bit intimidating. While I'm all for it if necessary, will this be as difficult a task to undertake as some ppl have been saying?

[Motofool]

Originally Posted by Truant

.......... I was riding my 07 Ninja 250 up a slight incline to then make a U-Turn. I dropped my speed way too low and I felt the bike starting to tip over to its left...........

Bonus vid:

Link to original page on YouTube.

Originally Posted by Truant

Actually, opening the throttle is now more responsive than before I adjusted the valves. However, closing the throttle now completely dumps all power. I find that I can't coast as well as I used to - the bike jerks around more than before. Is this normal?

Also I've done a bit of reading into valve adjustment/carb cleaning and it looks a bit intimidating. While I'm all for it if necessary, will this be as difficult a task to undertake as some ppl have been saying?

It is normal; the engine has better compression now and when you kill the internal combustion (when closing the throttle) the inertia of the bike has to work harder to compress air inside the combustion chamber.

You can counteract the jerking at low speed using the clutch (allows the engine rotate a little faster than what the rear wheel lets it spin) and/or the rear brake (artificially loads and slows down the engine).

Both tasks are not difficult if you have appropriate tools and space to work.
The hardest part is to disassemble many parts to access the rockers of the valves and the carburetors and then put all that back into place again.

[csmith12]

Originally Posted by Motofool

Bonus vid:

You read my mind...

Gald you got it sorted out! As far as I can tell from your posts, everything sounds normal. Closing the throttle should dump all power, that's the point of closing it.

Ya know... I find it interesting that a low speed down has improved your bikes impression on you.

[MrAtom]

You're not the first person who's dropped their bike and had it perform better after. I dropped mine and it somehow clogged the idle jet, so I cleaned it all up and tuned my carbs after, and now it starts with no choke in mild to warm temperature