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Discussion Starter #1
I killed my battery by leaving the key on at work. I guess I am thankful no one stole it considering the neighborhood I work near. The key was on about 3 hours and when I got out to the bike there was no sign of life. Worse I used the hex key I kept under the seat on my cub and never put it back. I thought I had one more chance, I am on a big hill at work and I thought I would put it in 3rd gear and bump start it down the hill. The gauges got power briefly but the engine wouldn't fire. It was a long hill and it did the same thing 3x. I had to call my ex and ask nicely to bring me some jumper cables and hex key. Worst of all I had to eat dinner at a filthy Wendy's and I then had to ask a child how to work the soda dispenser.
 

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You mean to say you didn't get reversed into?? :laugh:

I like how you asked your ex "nicely"... Otherwise there would've been that very slight possibility that she would have wacked you upside down with the cables!

LoL.
 

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best to start in second, with as fast a runup as possible..
i did the same thing with cbr250r [3times in 3 yrs]
and she fired up first time with a clutch start
on my sloping street, but also on a lesser slope
at the destination each time..

there really is a difference between gears selected
and speed of runup.. i wouldnt use 3rd gear
unless on a steeply sloped road with a long
fast runup.. ie, it could start with less,
but to make sure..

also refrained from using the starter button
for 8 or more [4 runs each way] starts,
clutching her each time, until the battery
had a chance to build up charge..

anyway, without charging, she fired up
first time every time [except those 3 events]
for 3yrs [until stolen]..
so it can be done and she will build charge
over a few days riding, including a long ride
esp first time out..
 

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Discussion Starter #4
I think she would have still came but made me wait an hour or so.


When I had gone out to the garage to put the charger on her the headlight was burning bright when I turned the key on but I put it on trickle for 4 hours.
Also, when I jumped it with the car I took the cables off immediately and seemed like she wanted to stall for the first 2 mins but then it ran fine on the way home and no problems since. I was thinking maybe something reset in the computer and the ECU had to dial in the air filter and exhaust again.
 

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When you're bump starting with an EFI bike and the power comes back, do you have to press the ignition button to get the fuel running into the engine, or does it naturally pull the fuel in?
 

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I hate modern electrickery. Bring back the days when bikes had three moving parts and two wires.......

There was a time when all you needed was enough jolts in the battery to produce a spark and the thing would run. If a battery had enough juice to crank then it would start.

Now, with engines in both cars and bikes using microprocessors, things aren't necessarily straightforward and there are literally a thousand ways the darn thing can go wrong. Modern electrics can even just go off in a sulk, apparently working but with mysterious stuff happening, like when the dash clock on my wife's Toyota died - so of course the electric windows on one side stopped working. What?

I also had a car develop intermittent starting problems one minute, then running rough the next. That turned out to be a sick battery that was apparently putting out enough jolts, but not the required amps, so the onboard computer got 'confused'. Again, what?

Nowadays, whenever a strange electrical problem occurs, no matter how subtle or slight, I swap the battery. Most of the time, that fixes the problem, even if the battery seemed to be holding and delivering OK.

I hate electrickery.
 

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I agree with you but if it was not for all that electrickery..we would not have gas sipping 4 cylinder cars that have more power than V/8 cars did 30 years ago and we would not have a single cylinder 300cc motorcycle that gets pretty well 85 + Miles/Gallon (Imperial) and goes 100 MPH.:nerd:
 

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So now your battery has lost considerable life because of a deep drain. A well taken care of (kept charged, no over charge or deep discharge) AGM battery will last at least 6 years, you will be lucy yours will last 2 more years. Once fully charged check voltage, then check again after letting it sit overnight. Lead acid is toast at 12.3v, when new they will read well over 13v, but best to use a load tester.

Also being FI it needs some juice, minimum voltage, to run properly that is why you had a hard time bump starting it.
 

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... There was a time when all you needed was enough jolts in the battery to produce a spark and the thing would run...
The battery provides power to a number of the components associated with the EFI system, however the battery doesn't provide spark for the ignition system... that is the job of the stator and ignition coils. Which is how off road bikes with kick starters and no batteries are able to start.

As DaBinChe said, a vehicle with EFI needs a battery with at least enough of a charge to power up the fuel pump, ECM, etc. in order to be successfully bump started. This is where a carburetor equipped bike has an advantage... they can be bump started with a completely dead flat battery (even those which have electronic ignition), as the primary job of the battery is to provide power to crank the engine.

Now, with engines in both cars and bikes using microprocessors, things aren't necessarily straightforward and there are literally a thousand ways the darn thing can go wrong. Modern electrics can even just go off in a sulk, apparently working but with mysterious stuff happening, like when the dash clock on my wife's Toyota died - so of course the electric windows on one side stopped working. What?

I also had a car develop intermittent starting problems one minute, then running rough the next. That turned out to be a sick battery that was apparently putting out enough jolts, but not the required amps, so the onboard computer got 'confused'. Again, what?

Nowadays, whenever a strange electrical problem occurs, no matter how subtle or slight, I swap the battery. Most of the time, that fixes the problem, even if the battery seemed to be holding and delivering OK...
That's very typical with today's cars... you could say the battery is the 'weakest link' in the system. If battery voltage drops just slightly below the narrow window of what's required by all of the various electronic systems, all sorts of odd things can happen. Cooling fan motors can start running even though the engine is cold, dashboard displays become wonky, engine idle is rough on first starts, the list goes on. I recently replaced the battery in my Saab 9-3, and had all of those things going on with the old battery. And despite those weird electrical glitches, that battery was still able crank the engine just fine... so cranking amps from the battery wasn't the problem, it was low battery voltage causing all the odd electrical problems.
 

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Make sure when you bump start to put in highest gear possible, not lowest. That way you aren't super hard on your starter. First gear puts way too much pressure the wrong way, a higher gear will help not fry any parts.


Just an FYI
 

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Make sure when you bump start to put in highest gear possible, not lowest... First gear puts way too much pressure the wrong way, a higher gear will help not fry any parts...
It has nothing to do with "not frying any parts". You'd never want to use first gear for bump starting, for the simple fact that using too low of a gear will cause the rear tire to more than likely skid on the pavement instead of turning the motor over.

However, if you use too high a gear for bump starting, you simply won't be turning the engine over fast enough in order for it to fire up.

Depending on the bike, third gear will usually work.

... That way you aren't super hard on your starter.
Bump starting (aka push starting) isn't going to affect the starter motor in any way. The starter motor bendix gear is only engaged with the flywheel ring gear when the battery is good, the ignition key is in the run position, and the starter button is pushed... otherwise the starter motor is completely disengaged from the engine.
 

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The battery provides power to a number of the components associated with the EFI system, however the battery doesn't provide spark for the ignition system... that is the job of the stator and ignition coils. Which is how off road bikes with kick starters and no batteries are able to start........
You took me literally, dintcha? :devil:
 

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I live on a hill, and my driveway is sloped enough that I can coast the bike from just outside my garage if need be. I even tried in on several bikes in the past just to make sure. It won't work on the Vespa though...no clutch. Good discussion. You never know when you might need to use this technique.
 

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It has nothing to do with "not frying any parts". You'd never want to use first gear for bump starting, for the simple fact that using too low of a gear will cause the rear tire to more than likely skid on the pavement instead of turning the motor over.

However, if you use too high a gear for bump starting, you simply won't be turning the engine over fast enough in order for it to fire up.

Depending on the bike, third gear will usually work.



You can definitely fry your starter bump starting your bike, but I agree with you, it makes the entire process much easier to do in a higher gear.
 

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You know what I thought about it and you are right, I have been told by several mechanics that it is hard on the bike but engine braking is essentially the same so..........
 

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ive found second best, on a nice sloping road,
with a good runup.. not enought to lock up
rear wheel, but close enough to that level
of force transmitted back into engine..

for me its always been best to immediately
clutch back in keeping high revs [5krpm +]
before smoothly releasing clutch again
still using higher revs, and repeating
high revs if necessary to stop again..

then going for a 20 min + ride without
stopping, or keeping revs up if necessary
to stop.. also not using starter for a week
of so of daily riding, clutch starting only,
to avoid stress on the battery..

always worked for me anyway..
 

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I would suggest that 1st gear is better for people that dump the clutch and leave it out as it is a lot easier to prevent the bike from stalling again at such low speeds. 2nd gear is better for people who finess the clutch (dump the clutch then grab it again as soon as the engine has turned over). Neither technique will work on a 300r with a completely dead battery. And people that use the starter while push starting only risk damaging their starter due to teeth not aligning because the engine is already rotating. They also risk their ecu due to the voltage drop while trying to start on a battery with low charge. The ecu requires a minimum voltage to run (usually about 9volts) and activating the starter with a low charge battery will cause the voltage to cycle up and down as it trys to kick in at the same time turning the ecu on and off rapidly while the engine is trying to start.
 
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The simple solution to this issue: Don't walk away from your bike with the ignition key left in the ON or RUN position.

I've seen more than a few riders who, rather than properly shutting the bike off using the ignition key, will out of habit (a bad habit) shut the engine off with the kill switch and then walk away, somehow forgetting that the electrical system is still powered up.
 
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