i used to practice bump starts on my way to-from work , just so if the worst happened , i could get home

if youve gotta bump start it, push it down hill or fast lol, hop on, put in second gear ( or higher) hold in clutch, ( with bikes key on, and choke set), stand up on pegs a bit, and simultaneously slam your a$$ into the seat while letting cluch go. as soon as bike fires, pull clutch back in

If you are going to Jump start from a car leave the car off. Your regulator/rectifier is not made to handle the cars charging output and can be damaged -part of it's job is to basically "eat" excessive power from the charging system.

A typical car battery will give you plenty of power for a jump start without the engine running. Once you get the bike running - let the bikes charging system handle the recharge ( you have to go for a good 20 minute ride or so..)/ get a battery charger/tender.

As for starting it every so often... that's ok but you should be riding it... short runs at idle- never really getting hot enough to burn off the combustion leftovers and make the oil nastier quicker ( More condensation too....).

It's up to you... but storing it  might be the best thing in the long run...
Oil change... pump the tires up extra.. battery tender....

Quote from: Jared on January 11, 2008, 06:11:54 AM

If you are going to Jump start from a car leave the car off. Your regulator/rectifier is not made to handle the cars charging output and can be damaged -part of it's job is to basically "eat" excessive power from the charging system.

GEEZZZ...We have gone full circle......go back to the start of this thread.

Yes....... the reg/rect governs how much voltage and current is released from the alternator into the bikes electrical system dependent on battery charge and power demand. It doesnt "eat" the excess voltage, it creates a high resistance path to ground through which it dissipates (or is shunted). .......BUT the voltage across the car battery you are jump starting from has ALREADY been rectified from 3ph AC to DC, and is being regulated to 12v by the cars alternator which unlike most bikes has an integral rect/reg

There will never be more than a 12v output from a healthy car alternator and the current it delivers depends solely on electrical load ie: how many lights/ accessories are turned on and how charged the battery is.

The variable component is current, voltage always remains constant and the bike will only draw enough current from the car to spin the starter motor and fire the plugs and the bikes wiring can accomodate this current by design, compare the thickness of the starter motor lead to the rest of the wiring........ You will not automatically get 100s of amps flowing through the bike by connecting it to a running vehicle with a 12v system (unless there is a ground fault on the bike)

Quote from: sledge on January 11, 2008, 12:52:30 PM
There will never be more than a 12v output from a healthy car alternator and the current it delivers depends solely on electrical load ie: how many lights/ accessories are turned on and how charged the battery is.

From:

http://www.familycar.com/Classroom/charging.htm

"A VOLTAGE REGULATOR regulates the charging voltage that the alternator produces, keeping it between 13.5 and 14.5 volts to protect the electrical components throughout the vehicle."

Quote from: sledge on January 11, 2008, 12:52:30 PM

Quote from: Jared on January 11, 2008, 06:11:54 AM

If you are going to Jump start from a car leave the car off. Your regulator/rectifier is not made to handle the cars charging output and can be damaged -part of it's job is to basically "eat" excessive power from the charging system.

There will never be more than a 12v output from a healthy car alternator

give or take a few

Quote from: sledge
give or take a few

haha yeah, but in this case, your "there will never be more than a 12v output from a healthy car alternator" statement is incorrect, considering that there will ALWAYS be more than a 12V output from a healthy car alternator. If it wasn't ~14V, the battery wouldn't charge. If you put a voltmeter across the battery terminals of a running car and it shows 12.0-12.5 volts? The charging system is not working, and you're not going to be driving for very long.

Anyway, some interesting info in this thread, I did not realize this issue has some merit since the bike's regulator works differently... I too had been jumping off a running car, not realizing this is making the bike's regulator work it's ass off. I'll have to give that some thought. Clearly as a lot of us have found though, the regulator seems to be ok with this for at least some period of time as many of us have been jumping off of running cars without issue. In fact, while we were working on some starting problems with my friend's GS, and the GS's battery was obviously not keeping up, we had the car running/jumping for a while as we made multiple attempts to start the bike. At least 10+ minutes, and the GS's regulator seems to be working just fine.

My vote now goes to jumping with the car not running until I figure this out for sure, thanks all! 

Quote from: sledge on January 11, 2008, 12:52:30 PM


GEEZZZ...We have gone full circle......go back to the start of this thread.

Yes....... the reg/rect governs how much voltage and current is released from the alternator into the bikes electrical system dependent on battery charge and power demand. It doesnt "eat" the excess voltage, it creates a high resistance path to ground through which it dissipates (or is shunted). .......BUT the voltage across the car battery you are jump starting from has ALREADY been rectified from 3ph AC to DC, and is being regulated to 12v by the cars alternator which unlike most bikes has an integral rect/reg

There will never be more than a 12v output from a healthy car alternator and the current it delivers depends solely on electrical load ie: how many lights/ accessories are turned on and how charged the battery is.

The variable component is current, voltage always remains constant and the bike will only draw enough current from the car to spin the starter motor and fire the plugs and the bikes wiring can accomodate this current by design, compare the thickness of the starter motor lead to the rest of the wiring........ You will not automatically get 100s of amps flowing through the bike by connecting it to a running vehicle with a 12v system (unless there is a ground fault on the bike)

In laymans terms it consumes the excess voltage.....or "eats" it .  The bikes RR is designed to handle the bikes alternator output...not a larger vehicles.

Put too much through it enough times and it will fail. 

Who cares.  As mentioned, it works with the car turned off, so why add to the confusion?

I have jumped cars with mine off, other times there system is so completely dead I hook them up and run my car for a bit to help charge their system.

I wouldn't make it a habit though.  Use a battery charger if you have access to one.  The charging system on the bike/car can get pretty toasty when charging up a battery from scratch.  This is the reason that stuff tends to go out at the same time.  A bad battery will run the alternator at max duty cycle, and a weak alternator will result in low charge on the battery, which slowly kills it's ability to hold charge.

So I tried to jump the motorcycle and it didn't work. I then tried with the truck running and it still wouldn't charge. I had it properly connected with good connections, so I'm not sure what was wrong. I took the battery out of the bike and had it tested. They said it was in good shape. I bought a charger and it charged just fine. It cranks now, but doesn't start. I've since drained the battery twice trying to start it. I have it back on the charger and am looking at other problems. The spark plugs look ok. I think I might have some bad gas in it (It's been sitting since early November). It's also 15 degrees F out right now and it always has been a cold blooded thing. Battery is inside when it isn't charging. I think I'm going to pull the whole bike into my apartment, put some fresh gas in (maybe not in that order) and let it warm up before (taking it back outside and) starting it.

Ok, got it running. Amazing what a little ether can do. 

I have measured a few cars when they are running with multimeter's and most will be 14ish volts across the battery terminals.

So, the general consensus (without flaming) for a good motorcycle jump:

1) Attach the motorcycle leads first
2) Attach the donor positive first, then the ground last
3) Do not run the donor engine (generally we're using a car battery, and it's available reserve is plenty)
4) choke and hit the starter (assuming it's cold)
5) pull the gs's jump leads and clip one to the lines to prevent a short
6) adjust the gs's choke and once it's stable pull the donor's leads
7) warm up and ride somewhere to check your battery / leads / starter

Agreement ?