Cranking but no start

[pancho]

It's been five years this month since I got a Valk and joined the VRCC, and have seen posts about this subject from time. The first suggestion has always been to check the battery....   Well I would read these posts and let it go in one ear and out the other thinking that if the bike is cranking good, there is enough voltage to fire the ignition modules and coils.

 I had it happen the other day after three days of below freezing temperatures,, cranking just fine but no indication of spark..... Hmmm, I never would have suspected the battery from the way it cranked, my impulse was to start testing the ignition circuits.. but remembering the posts, I put my trickle charger on the battery for a couple of hours until it indicated a full battery. THe bike fired right up!!

Just goes to show that the accumulated knowledge on this site is invaluable and trumps what an individual may know or think. I guess the ignition module is very sensitive to input voltage. I did not take a voltage reading while the bike was cranking {should have} but I stand corrected in my assessment of the problem.

Thanks again guys,, the days are getting longer.

[Fazer]

Same thing happened to me a couple of times.  Crank but no start.  Trickle charge for an hour and away we go.  I have a new battery sitting on the shelf waiting for spring.

Your post has prompted the question--how do guys bump start these things if there is not enough spark from a depleted battery?  I have ready about it being done, but if there isn't enough battery juice to the fire the coils, how does pushing it change anything?????  Inquiring minds want to know.

[Chrisj CMA]

It's amps not volts that the ignition is most hungry for.  I've never push started a Valkyrie, but if it works with a battery just barely too weak to fire the ignition, maybe even at that low rpm maybe the alternator is helping?

[Gryphon Rider]

It's amps not volts that the ignition is most hungry for.

That's kind of like saying it's the water flow, not the water pressure, that gets you rinsed off in the shower.

When you bump start a vehicle, either your legs or the hill you are rolling down give you the energy needed to spin the engine; the battery doesn't have to supply it.  That lets the ignition have the battery energy that would otherwise be used by the starter motor, which is certainly sufficient to start the engine.

It's kind of like jogging and carrying on a conversation at the same time.  If you're in good shape, it's not hard to do.  If you're in terrible shape and start jogging, half a mile later you would be hard-pressed to even give single-word answers in a conversation with the fit lady running beside you.  If you were to stop running, wait 15 minutes, then get in a golf cart and drive alongside the fit jogger, you would have no problem conversing with her.  It's not that it takes a lot of energy to talk, but if all your energy is devoted elsewhere, that can make it impossible to talk.

[The emperor has no clothes]

I would be careful about rolling down a hill to bump start it. If it doesn’t start that push back up the hill will just about do a person in. 

[Fazer]

I did  bump start mine once rolling down a hill, but was with a full battery.  I just wanted to see how it would feel.  Very easy in third, or maybe it was fourth, gear. 

[Hooter]

My solution is I keep all my bikes on a tender all winter and into early spring. Then I don't worry about it.

[dancnman]

My other Interstate had a sweet spot of releasing the starter switch which would allow the engine to start when the battery was low. In other words, cranking it would not start, but release the switch and it would. Sometimes.

[RonW]

Your post has prompted the question--how do guys bump start these things if there is not enough spark from a depleted battery?  I have ready about it being done, but if there isn't enough battery juice to the fire the coils, how does pushing it change anything?????  Inquiring minds want to know.

I believe people meant that a battery is too low to symultaneously crank the starter motor in addition to powering the ignition coils at the same time. A starter motor can draw 70+ peak amps. The only circuit that doesn't have a fuse, just super duper wires instead. The coils themselves don't require much electricity to energize, since the coils are just lengths of copper wire wound in circles to radiate a magnetic field that collapses on cue. They have minimum resistance except for some back EMF. Ever noticed how thin the +12 wires are that plug into the ignition coils? I wouldn't even rate a coil a load while electricity is simply traveling through it from positive to negative terminal. Whereas, whenever the magnetic field in the primary secondary coil collapses, the primary coil is a generator of electricity into the secondary coil.

Bump starting allows the rear wheel to spin the engine after getting the bike going fast enough to release the clutch lever. At that point, the starter motor just cranks an already spinning motor instead of an engine at rest. Less electricity is needed and more electricity available for the other circuits. The method that I use is to pull in the clutch lever a fraction of a second after releasing the lever to allow the engine to continue to spin by itself. A couple of extra spins might make a different. The start button pressed in. If I suspect the battery is really on the brink, I roll on the throttle only and don't even bother pressing the start button. This prompts a question, I don't know if bump starting works better if you roll the bike in gear and hold the clutch lever in, or roll the bike in neutral than shift into gear.

[The emperor has no clothes]

Your post has prompted the question--how do guys bump start these things if there is not enough spark from a depleted battery?  I have ready about it being done, but if there isn't enough battery juice to the fire the coils, how does pushing it change anything?????  Inquiring minds want to know.

I believe people meant that a battery is too low to symultaneously crank the starter motor in addition to powering the ignition coils at the same time. A starter motor can draw 70+ peak amps. The only circuit that doesn't have a fuse, just super duper wires instead. The coils themselves don't require much electricity to energize, since the coils are just lengths of copper wire wound in circles to radiate a magnetic field that collapses on cue. They have minimum resistance except for some back EMF. Ever noticed how thin the +12 wires are that plug into the ignition coils? I wouldn't even rate a coil a load while electricity is simply traveling through it from positive to negative terminal. Whereas, whenever the magnetic field in the primary coil collapses, the primary coil is a generator of electricity into the secondary coil.

Bump starting allows the rear wheel to spin the engine after getting the bike going fast enough to release the clutch lever. At that point, the starter motor just cranks an already spinning motor instead of an engine at rest. Less electricity is needed and more electricity available for the other circuits. The method that I use is to pull in the clutch lever a fraction of a second after releasing the lever to allow the engine to continue to spin by itself. A couple of extra spins might make a different. The start button pressed in. If I suspect the battery is really on the brink, I roll on the throttle only and don't even bother pressing the start button. This prompts a question, I don't know if bump starting works better if you roll the bike in gear and hold the clutch lever in, or roll the bike in neutral than shift into gear.

Interesting. I’ve never used the starter motor when push starting.

[Jess from VA]

I know one thing for sure.

If you are lucky enough to enlist a couple young fellows to give you a hard push in a gas station parking lot, they especially appreciate it if you turn the key on before they work up a sweat.  

California dreaming.


Enough with the donuts.


I've twice push started my own bike.  Only had a slight down slope.  The trick is to not dump the bike while jumping on.


 

[Gryphon Rider]

Your post has prompted the question--how do guys bump start these things if there is not enough spark from a depleted battery?  I have ready about it being done, but if there isn't enough battery juice to the fire the coils, how does pushing it change anything?????  Inquiring minds want to know.

I believe people meant that a battery is too low to symultaneously crank the starter motor in addition to powering the ignition coils at the same time. A starter motor can draw 70+ peak amps. The only circuit that doesn't have a fuse, just super duper wires instead. The coils themselves don't require much electricity to energize, since the coils are just lengths of copper wire wound in circles to radiate a magnetic field that collapses on cue. They have minimum resistance except for some back EMF. Ever noticed how thin the +12 wires are that plug into the ignition coils? I wouldn't even rate a coil a load while electricity is simply traveling through it from positive to negative terminal. Whereas, whenever the magnetic field in the primary coil collapses, the primary coil is a generator of electricity into the secondary coil.

Bump starting allows the rear wheel to spin the engine after getting the bike going fast enough to release the clutch lever. At that point, the starter motor just cranks an already spinning motor instead of an engine at rest. Less electricity is needed and more electricity available for the other circuits. The method that I use is to pull in the clutch lever a fraction of a second after releasing the lever to allow the engine to continue to spin by itself. A couple of extra spins might make a different. The start button pressed in. If I suspect the battery is really on the brink, I roll on the throttle only and don't even bother pressing the start button. This prompts a question, I don't know if bump starting works better if you roll the bike in gear and hold the clutch lever in, or roll the bike in neutral than shift into gear.

Interesting. I’ve never used the starter motor when push starting.

Neither have  I, nor have I ever thought of doing it.  One more thing to think of when pushing a bike and leaping onto it while not getting my legs run over by the saddlebags might just be one too many things for my already-stressed (by my bike not starting as expected) mind to handle.

[1NorthRyder]

I was stuck on the bridge crossing the border last year with the bike off but listening to the tunes and killed the battery just before the customs booth so no slope. I was surprised at how little forward movement I needed go jump start the bike.

[oldsmokey]

Much the same as a 1500 wing. Not enough juice for both, but a short roll and a bump,, away it goes.

[The emperor has no clothes]

Your post has prompted the question--how do guys bump start these things if there is not enough spark from a depleted battery?  I have ready about it being done, but if there isn't enough battery juice to the fire the coils, how does pushing it change anything?????  Inquiring minds want to know.

I believe people meant that a battery is too low to symultaneously crank the starter motor in addition to powering the ignition coils at the same time. A starter motor can draw 70+ peak amps. The only circuit that doesn't have a fuse, just super duper wires instead. The coils themselves don't require much electricity to energize, since the coils are just lengths of copper wire wound in circles to radiate a magnetic field that collapses on cue. They have minimum resistance except for some back EMF. Ever noticed how thin the +12 wires are that plug into the ignition coils? I wouldn't even rate a coil a load while electricity is simply traveling through it from positive to negative terminal. Whereas, whenever the magnetic field in the primary coil collapses, the primary coil is a generator of electricity into the secondary coil.

Bump starting allows the rear wheel to spin the engine after getting the bike going fast enough to release the clutch lever. At that point, the starter motor just cranks an already spinning motor instead of an engine at rest. Less electricity is needed and more electricity available for the other circuits. The method that I use is to pull in the clutch lever a fraction of a second after releasing the lever to allow the engine to continue to spin by itself. A couple of extra spins might make a different. The start button pressed in. If I suspect the battery is really on the brink, I roll on the throttle only and don't even bother pressing the start button. This prompts a question, I don't know if bump starting works better if you roll the bike in gear and hold the clutch lever in, or roll the bike in neutral than shift into gear.

Interesting. I’ve never used the starter motor when push starting.

Neither have  I, nor have I ever thought of doing it.  One more thing to think of when pushing a bike and leaping onto it while not getting my legs run over by the saddlebags might just be one too many things for my already-stressed (by my bike not starting as expected) mind to handle.

Yes, it seems it would require the synchrony of someone more talented than I. 

[RonW]

I’ve never used the starter motor when push starting.

Alrighty. Roger that.

[Firefighter]

In the late 70's I ran out of gas in my 66 ford F150 standard transmission, and drove about a mile to a gas station using the starter! Anyone else done that?

[ridingron]

I've never used it that far but have used it to get off the road.

[gregk]

I had to get a push start up in Canada once when the batt.died on my Venture years ago. 3 guys,  sw. on believe 2nd gear with clutch pulled in  till we had a little speed on level ground an popped the clutch. It took right off. Had to do Twice an then I got a new battery.

[JimBob]

I also experienced the 'crank but will not start UNTIL I released the starter button'.
Seems to me that for my bike, the starter would put enough load on the battery that the voltage would drop, enough so that the ignition would not 'spark' the plugs.
As soon as I released the starter button, the engine (still turning) would fire right up.
Started looking into it, and  reading the factory shop manual, found that the ignition has a circuit that pulses the PRIMARY side of the coils with approximately 100 volts.
Maybe THIS circuit is what needs the 'full up' voltage of a completely, fully charged battery in order to function.
Too lazy to dig out the oscilloscope, I decided to just keep the battery 'topped up' with a tender instead.
But.... if I go to start it, and it is not cranking at 'energetic' speed.... if it is cranking just a BIT slow, I don't beat it to death. I put the Valk on the charger and fire up my trusty Buell. (The Buell shakes and quakes, but if it will turn over, it ALWAYS starts!)

I am new to the Valkyrie, and new to this forum.
I GREATLY appreciate the knowledge that the long-time members have shared and posted.
The factory service manual is valuable, but these are complex machines, and there are a JILLION 'tips and tricks' that EXPERIENCE and INGENUITY teaches, that is not in 'the books'!

[RonW]

I also experienced the 'crank but will not start UNTIL I released the starter button'.

• Maybe THIS circuit is what needs the 'full up' voltage of a completely, fully charged battery in order to function.

It seems to be the case. Earlier, I stated that the ignition coils aren't even a load. It doesn't take a lot of voltage to energize the coils since they're only a coil of copper wire with electricity running from their positive terminal to their negative terminal. And copper wires have barely any resistance. And only the primary coil is dependent on the battery voltage. Apparently the primary coil does seem to require a voltage above 9.5 volts or something like that. If the starter motor drops the battery voltage below that bottom line voltage, the primary coil is incapable of radiating a strong enough magnetic field to induce a strong enough voltage into the secondary coil for the secondary coil's voltage to jump the gap in the plugs. So, on.