Topic: coils

[neilc]

can i run stock point set up with these coils?

[neilc]

another pic of coils i think they are from a 650

[bjbuchanan]

Yup

You gotta check primary resistance and those coils are probably down around 2.8-3 ohms. Use a ballast resistor, hondaman sells an easy plug and play kit for 19$. I'm a DIY type but you can't really beat it with the connectors in place already. You can specify the ohms you need so that you get back around the desired 5 ohms.

With the lower primary resistance you will go thru points faster and use a little more juice. The fact you have a 750 makes the additional current less important but is still a fact. Check primary resistance by setting to lowest ohm setting and connection from the 12v input to the wire that goes to the points for that respective coil

[RAFster122s]

650 coils are not compatible if I recall a recent thread where the subject came up and hondaman weighed in, he indicated they were not a good choice.

[Bootlegger56]

I agree with RAF....I asked HM about them for my 550 and he didn't recommend them due to the additional load on the weak charging system.  The 750 might be a different story.  I know that HM does sell a kit to use 3 ohm coils on the 750 system.  Drop him a line.  If you make a buy from him you wont be disappointed!

[neilc]

how to contact hondaman

[70CB750]

how to contact hondaman

Send him a PM:

http://forums.sohc4.net/index.php?action=profile;u=2043

[bjbuchanan]

Check that primary resistance. If it is right around 3 ohm you can use the ballast resistor. If it is lower then don't run em because the coils will overheat. They overheat because they weren't designed for that type of ignition

[neilc]

how do i check resistance,do i put my meter at power in to the coils

[bjbuchanan]

I said earlier in another post but anyway you set your multi meter to the low ohm scale. Probably like 20 ohm or something and touch your positive and negative leads to the 12v POWER IN and the wire that goes to your points. Stock honda blue or yellow or whatever your coil color is. In either case it is leads touching the small wires, not your spark plug wires.

If it is coils that "will" work it will be right around 3 ohm and up. Don't forget to get your test error out by first touching your leads together and seeing what the meter reads. Probably read like .2 ohm on the cheapie meters.

2.8 ohm and upward will work, there are production tolerances tho dead on 3 or 5 is obviously nice. Any lower primary rating and it is for a transistor style ignition or later electronic ignition and the coil will get much too warm and die and also pull unnecessary amperage killing battery voltage and the killswitch

[neilc]

I get like  5.33 ohms

[bjbuchanan]

Then use them. Stock for the 750 is 5 ohms so you are apparently right on the money

[neilc]

thanks 4 the help

[Black 750K8]

So he does not need the resistor correct?

[bjbuchanan]

No resistor necessary K8.

[neilc]

getting too aggrivated,can't even get a accurate ohm reading now tried 2 meters,i must be doing it wrong,one wire from meter to 12v (with ignition on) other to one side of the coil is the only way i can get any reading and that comes up 5.74

[neilc]

they are marked AW82 on them

[neilc]

okay i watched a video of how to check coils and i get 4.7 ohms wil this work with points or should i go back to electronic ignition,it ran fine with that set up,but would still prefer points set up,i know i am beating this to death