TOPIC:

Hi I'm new and i come from italy.I have a question..
I have one kawasaki kz650b from 1980 (my baby) but she have a little/big problem..in high speed is same she go to reserve (up &down )I made clean the carburetors and more but I have the problem again..I want try to change coil but in internet i find one pair from kz 750 from 1981 and I don't know if is good for my motorcycle
Tanks to all and sorry for my english
I'm happy that I find this forum

The coils will probably work, but they are not the right ones for your bike. you need to find coils off a bike with points ignition, the 81 KZ750 had electronic ignition.

Hello… my worry for the bike increases ... they give approximately two, perhaps also three years the bike not run good. The problem is that beyond the 100 km/h it loses blows, Like if it lacked fuel. In the carburettors the hands in many have put us .The last one has them practically takes apart piece to piece, cleaned up and to assemble… nothing to make. The problem seems that sufficient fuel does not arrive but could not be a problem electrical worker ??I have changed the cables of the sparking-plug, the sparking-plug, it lacks to me to try with the coils… my bike had a motor with number in kz650be and has the ignition electronic…What do you think??
Thank you to answer
what I write I translate with the computer because my English is not good and hope is translate well.. but I do not guarantee

Do you have the factory airbox on the bike? If not, have you rejetted the carburetors?

I hope of to have understood.. the airbox it is that one originates them and I have changed to all the series of collectors in rubber (originates them)
in order to eliminate eventual air infiltrations..Nothing

Mirkodj wrote:

I hope of to have understood.. the airbox it is that one originates them and I have changed to all the series of collectors in rubber (originates them)
in order to eliminate eventual air infiltrations..Nothing

Ok, you have an original stock airbox, and you have replaced the rubber manifolds and/or boots.
You mentioned that the coil might be failing and you intend to replace it. You might want to do repairs one at a time to you do not get confused. Replacing the coil may solve your problem, it may not.
But once you replace the coil you will be better able to track down the other problem.
I would strongly recommend you find a service manual for your bike, too. That way you can check all the obvious simple things that may solve problems.

The coils will probably work, but they are not the right ones for your bike. you need to find coils off a bike with points ignition, the 81 KZ750 had electronic ignition.

What is exactly the difference?

I have a `78 KZ650B2, with points. After riding it for
years, this June I had overvoltage, and it has blown all my bulbs and one of the coils.

I have replaced the burnt coil with a stock KZ650 coil, but it is in bad shape, the plastic is broken, etc.

So I have ordered new coils from ebay, they came from a `82 KZ750 Spectre.

Someone has also said the same, that they are for electronic ignition, not to be used with points. But I don't know why.

What I see, is that these new coils look exactly the same as the ones that I had on my bike when I bought it, and I assume that I had been riding for years using electronic ignition KZ750 coils. I haven't noticed anything.

How can you tell that a coil is for electronic or points? (I mean if you don't know the year and model, you just have the coil in your hand)

Last question: I am planning to install a Dyna S on my bike. Does it change anything in this area? I know that Dyna S was designed to be used with the stock coils, but is it an electronic ignition? Can I use electronic ignition coils with the Dyna S?

Cheers,
Gabor

Gabor, You raise a good question. The points style coils have 3.8 Ohms primary impedence. SOME IC Igniter (electronic ignition) coils also have 3.8 Ohms primary impedence and work just fine with points or an IC Igniter electronic ignition. Some coils used with an IC Igniter ignition use an inline ballast resistor; typically they are 2 to 2.5 Ohms primary resistance and the inline ballast resistor is 1.5 Ohms... the total resistance adds up to about the same but if you use these coils with points or without the ballast resistor, I think they may get too warm but folks have reported using them almost indefinitely without any trouble. Some motorcycles use CDI ignitions and these type ignitions use coils with MUCH lower primary resistance... from .7 to 1.5 Ohms and these coils DEFINITELY are a bad idea... they will burn up. The main point is to find coils that have a primary resistance of about 3 to 4 Ohms. These are called THREE OHM COILS. To check the primary resistance, use a multimeter with the meter set to OHMS which looks like an upsidedown U type symbol. Put the meter in 1x scale or 10x... that is the multiplier of the value on the meter is either one times the value or ten times the value. The lower scale ensures better accuracy as primary resistance will be low. There are two lugs on a coil; one for power and the other comes from either the IC Igniter or points. Put the POSITIVE lead on one lug with the meter in OHMS 1x scale and the NEGATIVE lead on the other lug. For most useful points/IC Igniter coils, you will see between 3.2 and 4.2 Ohms resistance. This also indicates there are no bare spots which cause shorts in the primary windings within the coil. If you ever go to a bike salvage yard and want to buy some coils, take a multimeter and test them. The secondary windings can also be checked in a similar manner but you will need to crank the meter to 20K Ohms scale as the resistance is much higher. The secondary windings can be tested by putting your probes on the spark plug lead contacts. The value should be somewhere between 12K and 20K Ohms in general and finding a value in this range will let you know that the secondary windings don't have a permanent short. Keep in mind that if you buy used coils, SOME may have shorts that only show up now and again... remember we are talking bare wires that may not touch all the time.

gee wrote:

The coils will probably work, but they are not the right ones for your bike. you need to find coils off a bike with points ignition, the 81 KZ750 had electronic ignition.

What is exactly the difference?

I have a `78 KZ650B2, with points. After riding it for
years, this June I had overvoltage, and it has blown all my bulbs and one of the coils.

I have replaced the burnt coil with a stock KZ650 coil, but it is in bad shape, the plastic is broken, etc.

So I have ordered new coils from ebay, they came from a `82 KZ750 Spectre.

Someone has also said the same, that they are for electronic ignition, not to be used with points. But I don't know why.

What I see, is that these new coils look exactly the same as the ones that I had on my bike when I bought it, and I assume that I had been riding for years using electronic ignition KZ750 coils. I haven't noticed anything.

How can you tell that a coil is for electronic or points? (I mean if you don't know the year and model, you just have the coil in your hand)

Last question: I am planning to install a Dyna S on my bike. Does it change anything in this area? I know that Dyna S was designed to be used with the stock coils, but is it an electronic ignition? Can I use electronic ignition coils with the Dyna S?

Cheers,
Gabor

The points-coils have about 4-ohms primary resistance.

The electronic-ignition-coils have about 2.5 ohms resistance.

Points-coils can work on electronic ignition, but electronic-ignition-coils should not be used with points. It wears the points out faster.

The Dyna S requires 3-ohm or higher coils. They don't recommend using the stock electronic-ignition coils because their resistance is too low, and could cause the Dyna to burn up. However, some on this forum have used 2.5 ohm coils with the Dyna and reported no problems. I would guess the 82 750 spectre used electronic ignition, but you should measure them as WG described, to be sure.

Also, did you solve the over-voltage problem? The Dyna will not like an over-voltage.

Post edited by: loudhvx, at: 2006/11/03 11:43