Electrics - a few basic questions
 

Hi all,

I am a self conessed numpty when it comes to the invisible mystery juice that makes our bikes run and I have a few dumb questions:

1. If I rig up some jump cables to my bike's battery (which is tucked away under the sump guard of my KTM 950), would I have to make sure that that the two ends (i.e. the ends not connected to the battery terminals) are seperate? What would happen if they touched each other?
2. What voltage do motorbike battreies throw out and is it OK to jump start a bike from a car battery? (I guess they run a higher voltage?)
3. If I were to carry some spare electrical wire top affect a bodge repair, what AWG rating wire should I carry?
4. How the hell do you use a voltimeter!?

Yup, these are dumb questions! Electrics have always been a mystery to me and this is the last bit of prep for a 6 month trip to the Americas. It may not sound like it, but I have now become fairly adept at some mechanical tasks on my bike, valve adjustments etc., but this stuff goes way over my head!

Any help greatly appreciated.
G

1) Don't let them touch they will short and eventually cause a fire.
2)Battery's are 12 volt but on a volt meter will show around 12.4-12.9 ish,it is fine to jump most bikes from a car.
3) Difficult one as I do not what you would be repairing or what your bike uses I would carry something around 20amp wire that would get me home but I have a different bike.
4) If you are only measuring volts switch it to the volt setting and the red wire to positive black to negative, if you are measuring battery voltage if you are checking voltage from a wire negative to earth, frame is good,and the positive to the wire. My best advise is to get someone who knows what they are doing to give you a lesson in the basics.

As a slight addon to number 4 above, some bikes do not use the chassis as an earth, so you need to know this fact for your particular bike, get a service manual and read it to find this bit out.

Getting a few basic lessons to start with is the best shot, get him to show if a bulb is getting power so you can check if it a blown bulb, or something else, simple things like that.

If you want to take some cable, just get some basic figure 8, 2Amp red/black stuff. This at least should not burn out if used most anywhere, except high current circuits, like ignition and lights, but if you have a problem there, it will be beyond you.

My advice would be to take none, that way you cannot get yourself into deeper trouble with only a very basic or non existing understanding of how to fix something. Unless you are going a long way from the beaten track, there will be a motorcycle shop of some sort on your travels, and most of the Americas have bikes, not your sort, but they have bikes, and know how to fix them, so they should be able to work something out.

Good luck
TS

1. If you attach jumper cables to your battery, don't let the other ends touch. It'll effectively short the battery terminals together. If the battery is hard to get to and you're worried about it going dead, a car style cigarette lighter plug can be used as a charging point. You just need a cable with a male lighter plug on either end. One in your plug, one in the vehicle with the good battery. You'll want to install it with 14 ga. wire and a 20 amp fuse.

2. 12 volts, no problem at all jumping them from a car. Both systems are 12 volts. Amps are the biggest difference between motorcycle and car batteries, and that's not a worry. You pull amps with your devices, you don't push them. Your battery will only take however many amps it wants, so long as the voltages match. Bear in mind however, that a good battery will actually read about 12.8 volts across the terminals.

3. I'd carry a few feet of 18 ga. If the repair is on a wire bigger than that, you can double up the 18 ga. until you get to where you can make a proper repair. It's small and light enough to be easy to work with, and heavy enough for practically every circuit on the bike. Make sure it's stranded core. For extra special fun, if you've made a cigarette lighter jumper cable, you can always cut that up for emergency wire. It'll save carrying two pieces.

4. Measuring Stuff with a Multimeter - For Dummies