Topic: Jump starting a bike,from a vehicle Pro's/Con's

[byidesign]

I want some opinions here....
    The Honda service rep ,said that
   a bike should not be jump started from a
      RUNNING vehicle, as sometimes a running
    vehicle runs at up to 16volts,
       and can potentially damage the bikes
      charging system ,or CDI.
              Only to jump from a vehicle that is off..
       or better yet a good fully recharged battery
          {time permitting}
                When I mention this to people , I get told
          That it's Bulls@*T  "never hurt it"{the bike} etc...
             I have vehicles that run at @15v alternator running voltage
                and the manuals say acceptable{for cars/trucks}
                   and bikes no longer spark after being jumped
                from a running vehicle,
                 Soooo.........
                     what have you,all seen happen from this.....
                           Thanks
                                  Bruce

[Chris Liston]

I've jumped bikes from cars and also bikes from other bikes.

With cars only do it when the car is NOT running.  The battery will put out plenty to start the bike without issues.  As soon as its started disconnect and let the bike warm up and ride.  Especially with our old wiring I would not chance overloading it with running car volts...

[Raul CB750K1]

Oh no, another dead horse beaten. If TwoTired read this expect a long post... HAHAHAHAHA


Raul


Wink Wink TwoTired!

[dusterdude]

yea,im sure its coming.

[hcritz]

Hey Chris.
Probably better to not use a running car!
On a bike with a true regulated alternator (like ours)...probably wouldn't damage anything in the charging system...but that's a lot of current for our little batteries to try and absorb so quickly.
For a bike with a permanent mag. rotor...and a Zener diode type regulation...it's deadly! The diode can't come close to handling the kind of amperage that a typical car alternator can generate. This goes for your riding lawn mower/snow blower etc. as well.
Haven't see some of the older post...but I'll bet there are lots of other reasons not to as well...
Straighten me out on this if I'm wrong T-T...

[smashme33]

 When I was in high school, I fried the electrics in a Suzuki GT750 using a running car. From that one ugly experience, I would say to shut the car off. The bike is shouldn't suck up so much juice that you'll have to run the car. If it does, you'll need more than a jump.

[smashme33]

The bike is shouldn't

Sorry about the bad grammar, still on the first coffee this morning!

[Zeke]

Yah, anyway, as long as the car's battery is charged (12 - 13 volts) it will start a puny motorcycle engine.

So why not play it safe and leave it off?

Zeke

[Pinhead]

So, let's say that we do fry something with the higher voltage. What would be the first to go? I could see the zener regulator going in a permanent magnet alternator. What about the ignition? What is the weakest link?

[Bodi]

The only problem would be with the battery, it isn't made to have high charging current. It won't be damaged in a jump start though, it would take longer to hurt a good one. I wouldn't jump the bike to a running car and leave it like that for more than 5 minutes or so though.
With the car running and supplying 14.5V to the bike, the rest will be fine. The regulator is a normal car type, it will just shut the field off without damage. The rectifier will be reverse biased and will conduct no power. The stock points ignition won't be bothered. Electronic ignitions like Dyna or Martek are made to handle battery float voltage, so no problem there.
Other bikes with electronic ignition, different alternator types, etc. could be damaged. I wouldn't try it with 2-strokes as I have heard of very expensive stuff being destroyed - try and get an ignition system for a Kawi H1.

[cb650]

Give the starter a rest every minute or so.   The car battery will last longer/stronger.




                  Terry