Kawasaki Motorcycle Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
2007 Kawasaki Ninja 250

8000 miles
Newish park plugs
New premium gas
New oil/oil filter

Bike is slow to warming up (idk if thats normal, probably is).

When I'm driving, the tachometer will just drop to 0 then go back to normal randomly (even though the actual RPMs aren't changing).

Backfires at least once or twice when riding for 15-20 minutes.

When driving (mostly at high speeds above 55) the engine will cut out randomly for roughly 0.5 seconds, sometimes multiple times within a few seconds.

It will sometimes stall when coming to a stop, but then starts up fine on reserve (even with a full tank).

ANY IDEAS?! I'm lost.
 

·
Registered
Joined
·
4,807 Posts
First thing to check is that battery connections are clean and tight.

Post back with how that works out.
 

·
Registered
Joined
·
4,807 Posts
It will sometimes stall when coming to a stop, but then starts up fine on reserve (even with a full tank).

ANY IDEAS?! I'm lost.
Are you saying that you have to put it on reserve for it to start?
Any recent work on it?
Has it been getting gradually worse or did it just start doing it one day?

Post back.
 

·
Insect Impact Analyst
Joined
·
789 Posts
Sounds to me like something is either not connecting properly or shorting to ground. I would pull the seat/fairings and tank and take a good look at the wiring harness for any worn spots or places where it looks like it may be rubbing against something. Take all of your connectors off and clean them really good with contact cleaner and a wire brush or emery cloth. By your description of things, I am betting you will find something around the ignition box or possibly even the coils. Do the visual inspection and clean the connectors, and if that doesn't resolve the problem, it's probably time to get a service manual and a multimeter and start checking things more thoroughly.

One quick question though. When you say the tach drops and then comes right back up, do you notice anything else electrical dropping off? Lights, etc? Or is it just the tach dropping? If the tach just drops, there is a good possibility that it's just a bad connection somewhere, but if everything blacks out for a second, then you may have a short to ground somewhere.

Intermittent electrical problems like this are the worst problems to have because they are so hard to track down. Good luck with this one and let us know what you find.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #7 ·
SFAIR

sometimes putting it on reserve will make it start back up, idk why. but also sometimes we dont have to.

take yesterday for example, we tested some things and took it for a spin. the bike was PERFECTLY FINE until about 25 minutes into the ride, the engine cut out for about 3-4 seconds, then kicked back on and then my muffler backfired really loud. this happened about 3 times within a couple minutes, then the bike ran PERFECT again for the remainder of the trip.

it has been getting worse over a few months with the initial symptoms being the engine cutting out for like 0.5 seconds multiple times but no back firing and no tach dropping.


STICKBOY

we have checked all connections and all grounds.

the tachometer drops and bounces around but sometimes with no other symptoms. sometimes it drops and bounces with the engine cutting out briefly.

we are going to be checking the black/yellow wires coming out of the stator soon.
 

·
Registered
Joined
·
26 Posts
sounds to me like a spark problem, the petcock position thing might just be a coincidence. The problem with an intermittent ground is that they usually only happen when you're riding because of the vibrations and movements of the bike cause the wires to move around. I'd try leaving your bike running while going through every wire and wire bundle and shaking and tugging on them trying to recreate the conditions they face while being ridden. I had a ZX7 that did the same thing, it would die all of a sudden and wouldn't even turn back over. After a while it would just start back up, turned out to be a loose connection in the wire coming out of my kill switch, it only did it while riding though because it was the only time it moved.
 

·
Registered
Joined
·
4,807 Posts
One thing to know in order to narrow down the problem...do the front orange running lights go out when it cuts out? Maybe you can tape a piece of cardboard to the front of one so that you can monitor its reflection?
Knowing this would eliminate a lot of tail chasing.
I do not think that the stator is the problem.
 

·
Insect Impact Analyst
Joined
·
789 Posts
I agree, it's definitely not a stator problem. My money is still on the ignition box connector or the wiring leading to it. It would be good to know if the running lights go out or not, or any other lights. But from what you described, it is definitely electrical. It backfires because there is still fuel being pumped into the engine with no spark, and all that unburnt fuel gets pushed into the exhaust. When the spark picks back up, the hot exhaust ignites the unburnt fuel, making it backfire. The petcock issue is more than likely just a coincidence, unless the act of moving it jars a connection somewhere and causes it to make contact again.
 

·
Registered
Joined
·
33 Posts
Wondering if you ever found the problem? I have the same problem on my vn800A and am trying to find the short. It almost seams that if I wiggle my seat right it will all come back lol. I just cant seem to make it happen with the seat off.
 
1 - 11 of 11 Posts
Top