How to jump start, bump start

[Andre]

Note the difference between jump starting a motorcycle vs. a car.

Edit: Here was a video link which I took out as there are to many things wrong with it in regards to modern motorcycles.

[grog]

so many things wrong with this guys advice. my job, or part of it is to assist vehicles with faulty/dis charged batteries. nearly 30 yrs experience. push starting a vehicle in my job is instant dismissal.  sparking up live leads near a battery, just not on. video should be deleted.

[Andre]

Not sparking up leads near a battery makes sense. Push starting such a bad thing? Could you please explain a bit more? Also other criticism and how to do it correctly, especially on the 14, are highly appreciated.

[Tony Nitrous]

so many things wrong with this guys advice. my job, or part of it is to assist vehicles with faulty/dis charged batteries. nearly 30 yrs experience. push starting a vehicle in my job is instant dismissal.  sparking up live leads near a battery, just not on. video should be deleted.

Same here Grog.
Some of the new vehicles are a bit "different" too !
Some folk should leave stuff alone if they don't know their vehicle.

[Tony Nitrous]

If we store Audi's they need to go on charge after a set time scale.
The battery gets a before and after reading, and gets topped up.

If they are left to go flat, when they are sent to a customer the car will
grass us up to the dealer to say its been jump started !

[Tony Nitrous]

A downside to bump starting old v new bikes is they are quite different electrically. Not so bad if the battery has a little charge, but bump staring a modern bike with a real dead battery means no fuel pump, electrical servo's, relays, sensors etc are powered up. Much less of an issue with a much older bike.


One thing that did spring to mind watching the clip was if someone tried to find a good earth by putting jump leads onto my frame like that I'd kick their arse. Not everyone has a scabby old Honda. 

[Andre]

A downside to bump starting old v new bikes is they are quite different electrically. Not so bad if the battery has a little charge, but bump staring a modern bike with a real dead battery means no fuel pump, electrical servo's, relays, sensors etc are powered up. Much less of an issue with a much older bike.

Thank you Tony, that is valuable information. Wonder how many more downsides there are to bump starting and, of course jump starting.

[Kiwifruit]

I had to bump start the 14 once after heated grips failed to turn themselves off. Took 3 of us to do it and I was worried as I'd heard on the old forum that doing so can loosen the clutch nut.
Got away with it that time but not keen to do it again. Could never have done it on my own either. Had to push it a long way.

[VladTepes]

Yeah the problem is that people see some advice that really only applies to older bikes and then assume it applies to all and apply it universally.

As Tony says on a modern FI bike if its stopped there will be no pressure / fuel to the injectors, no sensors / ECU comms so the bike knows what the hell is going on... it really can be a recipe for disaster.

An older bike on the other hand - there will be fuel in the carbs ready to go, no computers (or at least usually none crucial to the operation of the bike) and soon.

If a bike has a kick starter, use that.  If not, use the battery.  If battery is flat, power up the bike from an external source (ie another  battery, via cables - aka 'jump start')  but do it right and doit carefully.

Well that's my approach anyway.

[Andre]

@Kiwifruit Thank you for the info on the clutch nut. That is the killer argument against bump starting even when there is still enough juice in the battery except for turning the starter.

As to jump starting, I haven't heard much here. What about the difference between jump starting a motorcycle vs. a car? Meaning that the car's engine should not be running when donating the juice? Assume that is true. Any other procedure points I should be aware of?

[grog]

Andre, too many catches/precautions to list. ive spent hours in training schools and still need to check each vehicles requirements. basically, modern cars/bikes have electronics. usually use around 5 volts. easy to fry. main rule is to not spike them. spikes are caused by running motors, attaching a lead without a spike protecter, sparking the lead as its attached. my jump boxes all have anderson plugs to attach to donor battery. clamps are fitted to dis charged battery without any power, then just simply connect anderson plug, no chance of a spark/spike. lots more to the process but thats the basics. eliminate spikes. as for push starting, lots of reasons not to. starter motors all have a clutch system, designed for protection. if the motor kicks back, wont turn, drive gear will slip. an electronic petrol motor without battery power will never start by pushing, ecu, injectors etc need good voltage. have seen a diesel that had discharged battery they towed it to start. problem was that injectors had stayed open due to low volts, electronic modern diesel, filled cylinders wit fuel. bent con rod, fluids dont compress. if theyd chaged battery or jump started, starter motor wouldnt have exerted enough force to cause the bent rods. sorry to go on. a very tricky subject but what i have to deal with everyday. if i stuff up, i pay.

[Kiwifruit]

Welding is a big issue for me. Those computers and ECU's sure can be fragile.
If I find I have a vehicle with a flat battery. I prefer to charge the battery rather than jump start.

[grog]

exactly correct kiwi, the way to go

[grog]

we just got 4 of these. amazing product.https://www.mtawa.com.au/membership/business-partners/new-products/item/2986-projecta-1500a-12v-lithium-jump-starter.html

[Andre]

@grog Many, many thank yous for explaining this!!!