1976 R75/6 Troubleshooting

[Ken in Oklahoma]

Ah now Ken . . . first few posts.

Thanks for all your soothing words, Airbear. I feel much better now!



Ken, feeling better now in Oklahoma

[Jimijam]

Salute! Another question- I read something about how you can't jumpstart this bike without a battery because it will fry the electronics. Is this true?

[Ken in Oklahoma]

Salute! Another question- I read something about how you can't jumpstart this bike without a battery because it will fry the electronics. Is this true?

I'm not sure I understand your question. If you're talking about jump starting your bikes dead battery with a known good battery (such as a car battery) I see no problem as long as the bike's battery is just dead and not shorted internally (which would be a vanishingly remote happenstance). Why? Because a 12V (nominal voltage) car, or truck, or whatever battery you choose to do the jump starting will only have 12V available, just the same as does a 12V motorcycle battery. No matter how many amp hours a car battery might be rated at, it is still just 12V. The car battery cannot "force" the motorcycle's electrical system to "accept" more current than it normally can accept.

Now, what if you want to jump the car battery into your motorcycle, with the motorcycle battery missing? In other words, the car battery remains in the car, but electrically it might as well be residing in the bike. Again, no problem. Again, the motorcycle is only "sees" 12V, just as it does with its own motorcycle battery in place.

There is one point of concern. You must observe the usual protocol when jump starting a vehicle. That is, the last jump cable connection you want to make is the negative jumper cable end to a ground location on the car, probably something like an alternator bracket. The reason you're doing this is that there is always a remote chance that there may be an internal fault in the motorcycle battery (or the car battery for that matter) that could create an arc upon making that last electrical connection. That can ignite any hydrogen gas in the battery or the vicinity. In other words, a battery explodes. The whole idea is for you to be physically away from both batteries in the event of an explosion. The greatest danger is the sulfuric acid rather than the actual explosion of the battery.


Ken

[Duane Ausherman]

Ken, I was using an old car battery with a small charger as the power supply for some of my radio equipment. I get really good batteries for free from the local auto parts store. However, this time I sort of forgot to check to battery temperature from time to time to detiremine the battery condition/capacity.

One evening the battery exploded. It did some $7000 of damage to the room and equipment. The top of the battery blew upwards with enough power to damage the ceiling. Yes, the major damage was due to the acid. I wouldn't discard damage from the explosion.

As I related this story to others, I started hearing other stories. Someone had a fender blown off of the car.

I am far more careful with batteries now. This all happened before I started doing the wireless work. Our batteries are so huge that a single cell weighs around 200 lbs. We have dozens of them in one battery stack. Accidentally crossing them with a tool can vaporize part of the tool. It is quite impressive. The current capacity is well over 10 times that of an arc welder.

[Major Softie]

Salute! Another question- I read something about how you can't jumpstart this bike without a battery because it will fry the electronics. Is this true?

Urban myth. People with with no understanding of electricity have suggested that having more amps available than your motorcycle can handle will burn up components. This displays a thorough misunderstanding of how electricity works.

It has always been my belief that such stories get started this way: biker has dead battery. Biker jumps battery. Bike runs until turned off but doesn't charge battery. Biker takes bike to shop and learns it has dead charging system. Biker asks how this happened and ignorant guy at shop asks if he jumped it from a car. Biker says yes. Ignorant guy tells him he must have fried the parts when he jumped it from the battery. Biker goes on to tell story to every one he knows as he now has "proof" of phenomenon.

Entire time no one questions the fact that the reason he jumped it in the first place was because he had a dead battery, and that battery was dead because his charging system was already not working.


There is also a common belief that you may damage the diode board (a part of the charging system) if you hook up a nice big battery backwards (+ to - and - to +). This may well be true, but that doesn't mean you can't jump from a car; it would mean you can damage your bike if you hook things up backwards. Certainly more delicate electronics (more delicate than anything on an airhead) can be damaged by hooking up things backwards. I destroyed my Kissan Signal Minder on my Oilhead (a really fancy programmable electronic flasher that has programmable cancel time and can make your signals act as running lights) by hooking up a charger backwards (AND turning the bike on with it attached), but all the rest of the electronics on the bike weathered it just fine, and they are FAR more delicate and complicated than anything on an airhead.

[Ken in Oklahoma]

Ken, I was using an old car battery with a small charger as the power supply for some of my radio equipment. I get really good batteries for free from the local auto parts store. However, this time I sort of forgot to check to battery temperature from time to time to detiremine the battery condition/capacity.

One evening the battery exploded. It did some $7000 of damage to the room and equipment. The top of the battery blew upwards with enough power to damage the ceiling. Yes, the major damage was due to the acid. I wouldn't discard damage from the explosion. . . .

I take your point Duane. I've had only one experience with a battery explosion. That was when my Dad tried to start his Wagoneer and we heard a pop under the hood. The top of the battery had a hole in it and there was some sulfuric acid sprayed around. Obviously (now that you've pointed it out) there's a lot of hydrogen gas that can emanate from a battery. And the more gas that can collect the greater the explosive potential.

That battery explosion you had, was there also a possibility of hydrogen leaking and collecting as well? I wasn't thinking much in terms of the hydrogen getting out of the battery case--and I should have done so.

Ken

[Jimijam]

Yeah jean, the seat is completely rusted out and shot. It had vines growing out of it and was basically part of a nearby hedge. Today I'm replacing the fuel line, Does anyone have any intelligence on this?

[Jimijam]

Salute! Another question- I read something about how you can't jumpstart this bike without a battery because it will fry the electronics. Is this true?

I'm not sure I understand your question. If you're talking about jump starting your bikes dead battery with a known good battery (such as a car battery) I see no problem as long as the bike's battery is just dead and not shorted internally (which would be a vanishingly remote happenstance). Why? Because a 12V (nominal voltage) car, or truck, or whatever battery you choose to do the jump starting will only have 12V available, just the same as does a 12V motorcycle battery. No matter how many amp hours a car battery might be rated at, it is still just 12V. The car battery cannot "force" the motorcycle's electrical system to "accept" more current than it normally can accept.

Now, what if you want to jump the car battery into your motorcycle, with the motorcycle battery missing? In other words, the car battery remains in the car, but electrically it might as well be residing in the bike. Again, no problem. Again, the motorcycle is only "sees" 12V, just as it does with its own motorcycle battery in place.

There is one point of concern. You must observe the usual protocol when jump starting a vehicle. That is, the last jump cable connection you want to make is the negative jumper cable end to a ground location on the car, probably something like an alternator bracket. The reason you're doing this is that there is always a remote chance that there may be an internal fault in the motorcycle battery (or the car battery for that matter) that could create an arc upon making that last electrical connection. That can ignite any hydrogen gas in the battery or the vicinity. In other words, a battery explodes. The whole idea is for you to be physically away from both batteries in the event of an explosion. The greatest danger is the sulfuric acid rather than the actual explosion of the battery.


Ken

I meant to say start the bike without the battery, I have this jumper pack for cars so I was just going to connect that straight to the leads.

[Jean]

Some alternators/rectifiers are damaged if there is no battery in the circuit to charge.
Leave the "dead" battery in the bike...
Likewise... follow instructions above. make the last connection AWAY from the "dead" battery AND DISCONNECT that one first after the engine is running.

[Ken in Oklahoma]

I meant to say start the bike without the battery, I have this jumper pack for cars so I was just going to connect that straight to the leads.

I don't know much about "jumper packs" but if they are for all practical purposes a 12V battery I see no harm in removing the bike's battery and running the bike off the jumper pack.

But I also see no particular need to remove the bike's battery if you use a jumper pack. What would this buy you? As I see it the bike battery will be along for the ride, but so what? Unless there's a dead short in your bike battery the bike should continue running fine. (There are 6 cells in a 12V battery and all 6 of them would have to be a dead short for the whole battery to be a dead short.)

For myself I'd want to know more about my existing battery. I'd want to put a charger on it for a significant time and see what I've got. For that, after it was charged for a few hours, I would take it to an automotive supply store and have them do a CCA (cold cranking amps) test on the battery. The results of that single test will tell you a lot about your existing battery and if you need to bark up another tree or not.

Ken