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Discussion Starter · #1 ·
Would a battery strong enough to crank the engine over, but almost weak enough to click the starter motor also cause the bike not to start?

I have fuel.
I have spark.
I have compression.
I have air.
I have all the basic elements of a combustion engine there.

Bike just refuses to fire up. And I am completely out of ideas.
 

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A weak battery can cause the starter to spin (and even make the tach on my bike go to redline), but all you hear is a "whirring" noise and some clicking. Usual symptom for me was engine tried to turn over a few times, then it just gave up and the starter spun really quickly.
 

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If the starter is just spinning, NOT cranking the engine, then it's a mechanical problem with the starter gears.

if the engine is cranking, and not starting... well that's something else.

if you can see sparks with the plug out of the engine, that doesn't NECESSARILY (though with good plugs is a good indicator) mean you're getting spark (or at least proper spark) under compression. test the coils. Replace the Plugs too why not.
 

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with a multi-meter.

also, it wouldn't be such a bad idea to clean out and refreash the spark plug wire ends either. it could just be as simple as a contact issue. the plug boots unscrew, cut off about a 1/4 inch of the wire, reattach and clean the boot. use a lithium grease to keep it clean.

try that first. both sides.
 

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Knightslugger said:
If the starter is just spinning, NOT cranking the engine, then it's a mechanical problem with the starter gears.
Not to be contrary, but like I said, mine did exactly that with a weak battery. Charging (before I replaced the battery) for an appropriate amount of time, and it'd crank right up. This was even with a cold start with the dead battery and a cold start with the charged battery, so the conditions were the same. This happened for me more than once before I got the new battery. Bike would bump start fine.

I don't understand the mechanics of how the starter works on the bike, so I can't say what was physically happening, but I would hear the starter wirring and after a second or so the tach would jump up, but it was only the starter turning.
 

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ydant said:
Knightslugger said:
If the starter is just spinning, NOT cranking the engine, then it's a mechanical problem with the starter gears.
Not to be contrary, but like I said, mine did exactly that with a weak battery. Charging (before I replaced the battery) for an appropriate amount of time, and it'd crank right up. This was even with a cold start with the dead battery and a cold start with the charged battery, so the conditions were the same. This happened for me more than once before I got the new battery. Bike would bump start fine.

I don't understand the mechanics of how the starter works on the bike, so I can't say what was physically happening, but I would hear the starter wirring and after a second or so the tach would jump up, but it was only the starter turning.
It's pretty simple. the starter is attached to a gear and a chain that is connected to the flywheel. behind the starter gear is a clutch that only 'clutches' in one direction, not the other... like a come-a-long works. if the starter motor is just spinning and not cranking the motor, that clutch is broken or there's some other broken element in that system.
 

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Knightslugger said:
It's pretty simple. the starter is attached to a gear and a chain that is connected to the flywheel. behind the starter gear is a clutch that only 'clutches' in one direction, not the other... like a come-a-long works. if the starter motor is just spinning and not cranking the motor, that clutch is broken or there's some other broken element in that system.
Then why would a battery charge / replacement fix the issue? In fact, I experienced the behavior, switched out the battery, and then it started right up. I've had no other issues with the mechanics of the engine/transmission/clutch (other than common transmission issues like false neutrals and engine braking downshifts).
 

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ydant said:
Knightslugger said:
It's pretty simple. the starter is attached to a gear and a chain that is connected to the flywheel. behind the starter gear is a clutch that only 'clutches' in one direction, not the other... like a come-a-long works. if the starter motor is just spinning and not cranking the motor, that clutch is broken or there's some other broken element in that system.
Then why would a battery charge / replacement fix the issue? In fact, I experienced the behavior, switched out the battery, and then it started right up. I've had no other issues with the mechanics of the engine/transmission/clutch (other than common transmission issues like false neutrals and engine braking downshifts).
I have absolutely no idea. The problem with the starter just spinning and not cranking the engine is PURELY mechanical.
 

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Hopefully someone else will chime in, then. FOG? I'm not worried since the bike's been running fine otherwise. I think I saw this same behavior mentioned elsewhere on the forums, but I doubt I'd be able to find it through search.
 

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donkeyman said:
Bike just refuses to fire up. And I am completely out of ideas.
Did you try to pushstart it ?
 

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Discussion Starter · #12 ·
I used a car battery to boost start it. She started and ran for a few minutes. Then for about a second, the rpms shot up and the bike stalled. From my experience, that's the symptoms of fuel starvation. I couldn't get it started again after that. I tried sucking on the vacuum to draw fuel in, but then I started smelling fuel. The only thing I can think of is the float height. Can the height be measured using the clear tube method with the carb still on the bike? Cuz the carb would be tilted forward a bit.

I made this drawing to make it clear. Even though the carb is tilted, you still place the clear tube vertical? And if it's on the line, then it is perfect?
 

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I've never understood how floats get out of adjustment---gremlins,evil spirits?It's usually trash in the float bowl keeping the needle from seating.Didn't read the whole thread,so don't know if you cleaned the carbs.If not,do so.It could also be the battery.CDI ignitions need full power to fire properly.Yeah,once you get it running the alternator should take care of that,unless the battery has some bad/corroded plates shorting out and causing resistance.Batteries are cheap.Plugs are cheap.When at your wits end,really the only thing you can do is throw parts at it.Or expensive dealership.Then it's luck of the draw whether you get a competent mechanic.And sometimes they just throw parts at it too.
 

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Discussion Starter · #15 ·
IT WORKS!!!! YAY!

New plugs - old ones were fouled.
New battery - old one wouldn't hold above 11.5 Volts of charge.

Later tested the float using the clear tube test, one carb just overflowed with fuel. Opened it up and saw this little beetle/bug like thing inside the float valve hole but couldn't get it out. Blew it with compressed air and it came out the other carb float valve hole. The float heights were all off so I adjusted them to 17mm and tested the fuel level. PERFECT. Put everything back together, installed a Briggs & Stratton 60 micron filter, and it fired right up and ran beautifully.

I'm so happy after spending 2 weeks trying to diagnose the problem. Even managed to take it out for a spin and had a good time riding. :)
 
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