Coil resistance

[Bogi]

Hi guys, can somebody please tell me, what's the primary and secondary resistance on 1982 r65 dual coil?I'm seaching for a alternative replacement, because the original one is too expensive for me.Thanks

[Barry]

Primary is 1.5 ohms. Don't have a figure for the secondary but expect it will be  in the region of  7 - 10K.  You might not easily find secondary values for aftermarket coils anyway. Dyna coils are a common substitute but there are other cheaper ones available form Harley spares outlets.

[Bob_Roller]

Don't know what's available in your part of planet earth, but K100 bikes had two dual output cols, 1.5 ohms .
Also K75 bikes had three single coils, that seem to be used in place of the dual output coil .
Someone also made a posting about outboard boat motors using coils that are compatible with the R65 .

[Tony Smith]

Someone also made a posting about outboard boat motors using coils that are compatible with the R65 .

That was me. I am using mercury outboard coils on my R65. Can't tell you what model they are off, or even how old, I was simply let loose in the yard of a marine salvage yard and these (actually a double ended coil) were the first that looked "nice" and were 1.5 ohms. They cost me $15 so on principle I bought a 2nd set just in case.....

[Bogi]

I've found Beru zs283, only 20 euros.

dont know whats the primary resistance yet...what happens if I put coil that has different resistance?

[Barry]

Beru zs283 is a modern auto ignition coil with a primary resistance of 0.57 ohms. That is far to low and would likely overload your ignition module.

Slightly more ohms primary resistance is fine, it just means you would not have optimum spark energy but anything lower than spec will draw too much current through the ignition module which will cause it to overheat and risks failure. Possible exception might be the later 'purple' ignition module which has current limiting built in but even that was specified for 0.75 ohms.

[marcmax]

All this talk about coils got me thinking and I checked mine, closely this time, and sure enough the cracks are starting to appear. Hasn't been an issue yet but I don't want to wait until it is.

I did a search on fleabay for Dyna and found a new Dyna Brown 1.5 ohm coil that no one had bid on about to end. Placed a bid and got it for $10 and $5 shipping. It is meant for a Harley so the towers for the leads come straight out the side but for that price I can get creative with making a mounting bracket or put right angle ends on the leads.

[Barry]

I think you bagged a bargain !

[Bogi]

Thanks guys for your help.
One more question, if I put two 12v coils in parallel connection, the resistance should be 1.5 ohm each, right?also if I put two 6v coils, direct connection, they should be about 0.7 ohm each?

[montmil]

Consider the space and mounting requirements for two coils. Not a lot of available area under the R65's tank.

[Barry]

Thanks guys for your help.
One more question, if I put two 12v coils in parallel connection, the resistance should be 1.5 ohm each, right?also if I put two 6v coils, direct connection, they should be about 0.7 ohm each?  

Assuming you are aiming for a total resistance of 1.5 ohms then to achieve that with two coils in parallel they would need to be 3 ohms each.

Two coils in series would be about 0.7 ohms each.

[nhmaf]

I love the Dyna coils - no need to carry all that extra weight around and use up space with the single coil setups, especially the older airhead 6V coils.

[Bogi]

Thanks. I think, I will try to find Dyna coli, but it's not easy in my part of the world.

[professorfate]

I'm not having any luck with dyna coils. Had my second one fail last weekend. currently running on a Oldsmobile coil pack. What accel coil would work.  

[Barry]

Can't say without knowing the year of your bike.  Accel seem to do plenty of 3 ohm coils for points ignition and 0.7ohm coils for the 85 on models but there are no 1.5 ohm coils that I can see as an exact match for the 81-84 bikes.