TOPIC:

So, I have a 1980 Kawasaki Kz250, hasn’t ran in years and on Christmas I got my carb back from being cleaned ( I have no air filter yet), installed it and jumped it from my car, I have no battery, once it started the bike was revving extremely high like it was pinned, once I took the car off the bike it idled normal, is this normal for an old bike like this to pretty much pin itself cause I’m jumping it from a car? I now know your not supposed to cause it can damage the electrical system, I just found I odd once I took the car off it idled.

You knew it could damage the bike, but you did it anyway?

No, that is not normal.

Stop it.

I tried to start a KZ with a jump that had a completely dead battery... After it started I removed the jumper cables... The bike continued to run, but as soon as I switched on the lights it blew several bulbs and cooked the 20 amp main fuse.. I don't know why but I will NEVER try to start a KZ without a properly charged and in good condition battery again...

Jump starting a KZ from a car or truck is a bad idea. If it doesn't have a good battery you should simply buy a good battery rather than risk causing much more expensive damage by jumping the bike. After all, you will need to buy a battery anyway, so why take the chance on cooking the bike's electrical system? What's to gain? Ed

I would agree that jumping a motorcycle from a car isn't the best idea, but I have done it in the past several times when I had no other option. I my case the vehicle that I was jumped from was NOT running which should be a requirement when doing this. So whatever charging power was only supplied by the vehicles battery and not the charging system. I must say that the OP's issue seems quite odd and I have no idea why his bike ran high rpm when being jumped and went to low rpm when not being jumped. I would have thought with no battery in his bike it would have ceased running when not being actively jumped.

Rick H.

TexasKZ wrote: You knew it could damage the bike, but you did it anyway?

No, that is not normal.

Stop it.

Did you actually read the post or pick out tidbits and reconstruct it yourself and answered it? I said if you read it again I said I now know, I talked to someone afterwards about it being a bad idea,

My question it does it sound normal the bike pinning itself pretty much because I’m jumping with with a far bigger battery and larger charging system causing it to overcharge as I was told it’s called.

Rick H. wrote: I would agree that jumping a motorcycle from a car isn't the best idea, but I have done it in the past several times when I had no other option. I my case the vehicle that I was jumped from was NOT running which should be a requirement when doing this. So whatever charging power was only supplied by the vehicles battery and not the charging system. I must say that the OP's issue seems quite odd and I have no idea why his bike ran high rpm when being jumped and went to low rpm when not being jumped. I would have thought with no battery in his bike it would have ceased running when not being actively jumped.

Rick H.

Isn't it essentially like a car, where’s the alternator or stator in this case aids in keeping the vehicle running?

650ed wrote: Jump starting a KZ from a car or truck is a bad idea. If it doesn't have a good battery you should simply buy a good battery rather than risk causing much more expensive damage by jumping the bike. After all, you will need to buy a battery anyway, so why take the chance on cooking the bike's electrical system? What's to gain? Ed

Didn’t know till after jumping the bike that it was bad, thought since it was 12v I can jump it like anything else.

I know that people would have all kind of stories abut causing damages from jump starting a motorcycle from a "car" battery, but it would not cause any damage. We call it a "car" battery, but is the the same type of battery just bigger because the car has the room and could handle the weight. It's got the same nominal voltage, it just has more STORAGE capacity because is bigger.

.......if I had the space in a motorcycle and weight (of the battery) was not an issue, I'd mount a "car's" battery, or any bigger battery with same nominal voltage, in my bike any time for more CAPACITY and therefore, longevity..


Question: For those who understand the basic Kirchhoff's Current Law. V = I*R. …. If a nuclear aircraft carrier has one thousand (1,000) 12VDC batteries connected all in PARALLEL as auxiliary power, and I tried jump starting a motorcycle from this auxiliary power, .............................what would happen to the bike?????

My thoughts would be that while the cars charging system was present the bikes dynamo had no load and bike was able to rev high on choke. Once the cars charging was removed the bike had to take over, putting load on the dynamo and dragging the rpm down... There is no connection between the charging system and the throttle.., Fly by wire newer bike id maybe think different...

Don't get offended please when a member offers his opinion, after being here for years I know they don't mean it personally... They say it as corrective criticism to make sure you get the best out of the bikes mechanics...

The issue is not that it was a car battery but if the car was running or not.
Jumping from a non running car is no problem. The bike will only draw what it needs. If the car is running your jumping from the car battery and the car charge system which is much higher than the bike electrical components can handle.

hugo wrote: Question: For those who understand the basic Kirchhoff's Current Law. V = I*R. If a nuclear aircraft carrier has one thousand (1,000) 12VDC batteries connected all in PARALLEL as auxiliary power, and I tried jump starting a motorcycle from this auxiliary power, what would happen to the bike?????

DC connected in parallel increases strength and possibly AMP/Hour. Connected in series increases voltage....???