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How do you jump start a motorcycle, my attempt failed.

1K views 7 replies 3 participants last post by  KarlJay 
#1 ·
I had a problem with the battery over the past few months. I think I found the problem, seems this only happened after installing an iPhone charger. I guess it draws power all the time. I'll confirm this later and find/make a switched power source or something else.

So I tried to jump start the bike from a running car using jumpers from her battery to my positive on the battery and neg on the engine, then ground to the starter. After a few tries, she wouldn't turn over. I waited 8 minutes and STILL the starter wouldn't turn over.

Had it towed home, charged the battery and she turned over great. I'm sure it wasn't heat soak, and the battery has been on a few professional load testers and it fine.

My guess is a slow drain from the iPhone charger that stays on all the time.

My problem is that the jump start should have started the bike even without ANY battery. The light came on, pump turned on, etc... it just wouldn't even crank her over.

I use + to the battery and - to the case (chain adjuster) then - direct to the starter body on the other side... Waited 8 min and it still failed.

What did I do wrong?
 
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#2 ·
How was the connection made to the positive terminal, and what is the size of the wires used to jump it? If they are too small there won't be enough current to charge a flat battery quickly much less crank over the motor.

Past that I have no idea what the problem could be.

Rob
 
#3 ·
I don't now the size of the jumper cables, they were smaller than mine at home, but they are car jumpers and thicker than any wire on my bike.

I was clamped direct to the battery for + and direct to the starter for -.

I let it set for 8 min thinking that would transfer charge to the battery and that didn't seem to be enough.

I never thought a jump from a car to a bike could fail. The CA for the new battery is 180 vs a car in the 500~600 range. So it's like 1/3 the power of the car battery.

I'm thinking it has to do with the connection of the ground, but where do we jump to?
 
#4 ·
Hmmmm ... thick wires, a good connection to the positive at the battery, and grounded to the engine. Should have worked, but didn't.

Gremlins? Yeah, that's not likely unless Joe Dante is still pushing the movie in a way that is well outside of the normal advertising realm. And yes, it's still being shown in theaters.

The stinking lousy fates messing with you? Electricity has no regard for karma, so that's unlikely as well.

Defective jumper cables? I have seen that, but again not too likely.

An example of the insulating properties of paint? Yup. The first ground attempt was to the chain tensioner body, which did not work. It is painted after all. The second try was to the starter itself, which failed as well. The clue there is the difficulty of getting at an unpainted part, which after looking at it is a real bear. Where then? If it was up to me the best place is one of the front engine mount bolt heads after a quick cleaning with a shop towel and WD40 or the like. It's bare (if plated) metal and a goodly size for the current required. Frankly, any bolt head on the frame or engine would work nicely. Then there's pretty much anywhere on the exhaust system upstream of the mufflers. Plenty of options.

There you go.

Rob
 
#5 ·
So you're saying the painted engine caused the problem? I didn't know the engine was painted, but I guess it couldn't look that good after 13 years without being coated with something.

I guess what threw me off was the fact that the battery was actually taking on a charge, just not enough of a charge.

I think what I need is a jump point. A 6" battery cable from the - would do the job, maybe a copper tab mounted somewhere to the engine or starter bolt.
 
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