Jump-starting bikes?

**johnnyflash** · 14th November 2007, 20:41

Originally Posted by awful-truth

OTT but that's not what a slipper clutch is for - I think you're thinking of a sprag clutch. A slipper clutch is a torque limiting device to stop your rear wheel skipping on downshift while braking - it doesn't freewheel.

bummer..... slipper of the tongue

**smoky** · 14th November 2007, 20:56

Originally Posted by awful-truth

Some bikes are trickier than others, but I've never seen one that can't be crash started.

If you gotta have the clutch in before you can make the ignition circuit - how you gonna drop the clutch then!! Haven't worked that out yet.

Originally Posted by awful-truth

order. The negative to chassis is on the dead vehicle end, and the last connection made, and first removed.

In theory - as I was taught, your correct - but due to the nature of some bike electronics I feel more comfortable, and better results by dropping the connections onto the bike battery posts first (good solid connection to the bike battery) - then make the connections on the other vehical, last connection to an earth point. The risk of making the last connection to the earth point on your bike is your completeing the circuit on the faulty vehical and stray voltage/current is more likely to damage your electronic bits.

but your correct according to the experts

**Paul in NZ** · 14th November 2007, 21:15

Christ I'm glad all my bikes are dirt simple....

**Rhino** · 14th November 2007, 21:16

Originally Posted by awful-truth

Wrong order. The negative to chassis is on the dead vehicle end, and the last connection made, and first removed.

Correct. Way back when I was an apprentice auto-electrician, that was the sequence that was taught.

As was mentioned, never complete the circuit by connecting a lead to a battery terminal as it can ignite any gases due to recent charging of the battery. I had been an apprentice for all of around two weeks when I blew up a massive tractor battery by connecting it to a charger that was still turned on. The roof was around 10 meteres high and the top of the battery hit it.

**mdooher** · 15th November 2007, 06:45

Originally Posted by awful-truth

Is that a factory fitment? If it is, I'd be surprised if it's live with the ignition off.

Yep factory fit...yep live with ignition off.... yep I’ve upgraded the fuse on the bike and put a smaller one in my trickle charger cable. Since I don't use the power socket for anything else this works well for me.

Adding a water proof connection that looks like it belongs to the GSX250 was much more interesting...

**SVboy** · 15th November 2007, 07:05

Had to jump start my sv650 once-my fault-park lights left on. Couldnt push start it for the life of me! Ended up with my lungs hanging on my chest like deflated rugby balls! I wondered-between bouts of self applied cpr, if fuel injected bikes needed a minimum current if there was to be any chance of a push start. Ended up jump starting it, being very wary of frying the cpu, but there was no drama.

**vifferman** · 15th November 2007, 07:50

I spent too long last night with the key turned on and the engine not running while I was diagnosing an electrical fault in the confirminators. No real surprise this morning then when the engine wouldn't turn over fast enough to start. I didn't even bother trying to bump start it. Got the keys to #2's Peugeot, moved the remote reservoir for the Elka out the way, and connected negative to negative with the jumper leads. Stuck the positive on the Pug's battery, couldn't get the positive clamped on the VFR's battery, so held it there while I pushed the button. No problem.
It's almost never necessary to have the car running while using jumpers, as bike's started don't draw huge amps, so voltage spikes aren't much of a danger.
I've had to bump and/or jump start every bike bar I've owned, and the only ones that have given me any grief with starting have been the VTR1000 and the VFR750. The VTR was very hard to bump start: if you didn't leap up in the air so your full weight landed on the seat as you let the clutch out, it would just skid the back wheel. Always used 2nd or 3rd gear on every bike, as first is too prone to locking up the wheel (plus that's the way I was taught).
The VFR750 wasn't hard to bump start, but was problematic to start if you ran the tank dry, as the fuel pump only ran when the engine was running.

**Swoop** · 15th November 2007, 08:02

Originally Posted by vifferman

I spent too long last night with the key turned on and the engine not running while I was diagnosing an electrical fault in the confirminators.

Yup. Guys over at VFR World saying 4-5 mins at idle (not the x3 twit) is enough to suck the power out of the battery. Gotta love the powerful headlights on modern bikes.
My 750 has a proper lightswitch, Off/park/on, to alleviate that hassle.

**Pancakes** · 15th November 2007, 11:01

Originally Posted by smoky

If you gotta have the clutch in before you can make the ignition circuit - how you gonna drop the clutch then!! Haven't worked that out yet..............

Yeah but the ignition circuit isn't being used. You bike runs with the clutch out a? Your just going directly to run with a bumb start and yeah, singles need a good bounce on the seat and 3rd is fine and easy for less sporty bikes.

**Subike** · 17th November 2007, 17:33

Only ever tried it once on my yammy exsessive,never again, It worked , second gear, down hill, touch of the trottle, shit a brick!!! Hang on fast !!! I only weigh 74kg, so the bike a little heavey for my weight, but when it got going, it was off! I hung on and hit the kill switch, option was to let go and dump....not a choice. So I will NEVER try to crash start my beast again. Bought a new battery the next day. No more problems.