Hello,

I have a strange problem that I haven't been able to pin down. I was riding my bike last night, 1989 ninja 250, and it was running great. Suddenly the engine sputters and stalls. I pull over and try to start the bike but nothing, the starter doesn't even crank and the headlight shut off. However, my gauge lights are still on and my brake light still works. I get a jump from a friend and the bike runs again. Then I hear some backfiring and soon my bike stalls again in the same fashion as before.

The bike will sometimes start if I wait a long time but once it starts it idles very poorly. If I try to use any electrical equipment like the brake light or turn signals, the idle will be interrupted and the bike will stall. Today I had a chance to work on the bike a little bit and test the battery voltage. It was 13-14 volts unloaded and no less than 10-11 while cranking, maintaining around 12-13 while running. I also tested with only a known working car battery (bike's battery disconnected) connected and the result was the same.

I tested the bike again with no lights hooked up. Even then, the starter would only sometimes crank after given a break. Upon the starter moving, I had to give some gas to get the bike to start or sometimes apply choke. After it starts and idles the idle fluctuates in RPMs. I was able to kick it in first gear while holding the RPMs high and ride it forward a bit. Basically, the bike just runs really really bad, completely different from right before whatever it was "broke". She was running perfect before it sputtered and died last night. It seems to me like an ignition or electrical problem. Does this sound like a bad stator/rectifier/regulator?

I hope I'm not stuck lugging her down to a cycle shop for diagnostics. I hope somebody has some idea on what to do. Thanks in advance.

 

Hey man

it sounds to me like you have a ground problem. I'm not a bike mechanic but i think i'd be checking the battery ground where it goes th the frame. and if you have a control module i'd check it's ground too.
sorry i couldn't be much more help than that.
good luck
Gary

 

how old is the batt? It may be producing vlots but no or little amps. Put an amp meter on her and see how amps you get while cranking.

 

^^^^^^what he said ...........does it have a coil ?

 

Hey guys, thanks for the quick replies.

Today I ran a set of diagnostics on the battery, rectifier/regulator, and stator. All of which are in good condition. It's running a bit better today, I'm not sure why. I can actually get her to start every time and I can use my tailight and blinkers with no bad effect. I had just replaced the spark plugs and cleaned the carbs before this happened so took out the plugs, regreased them and put them back in snuggly. On a highway test ride today it all seemed to behave well except when I gave it WOT it started backfiring and sputtering a little.

I'll check the battery ground tomorrow and see what condition that's in. The battery itself is pretty new (few months). I've ruled that out of the problem as I've tested with a known good car battery connected by itself to the bike. Also, regardless of the current the battery can put out, the bike should still be able to run, even with no battery.

Again, thanks for the comments, hoping to iron out the rest of the problem tomorrow.