Alternative coil for airhead?

[The Other PaulG]

Hi,

Please, does anyone know of any alternative dual output HT coils that are suitable for airheads?

The bike's a '92 R100 GS P-D

Electrex offer a range at about £45-£55 which is preferable to the £110 charge for a 'standard' part, but none of Electrex's offerings have resistances that match what Haynes says an R100 needs.

Are there any other alternatives that people have used successfully?

Paul G

 

[Bubb]

coils

I seem to remember someone on AdvRider saying that Harley coils fit airheads.... sorry, but I cant remember which one they said....and I believe lots cheaper.

Im sure someone more knowledgeable than me can advise.

Ride Safe

Bubb

 

[Redboots]

does anyone know of any alternative dual output HT coils that are suitable for airheads?

I put a Silent Hektik unit on mine. I see they have changed the shape of them now.

BMW

 

[Steptoe]

A BMW K100 coil is a good fit, very cheap if buying used and ultra reliable.

Also just in case you might be thinking of buying off ebay - You can't use a K75 or K1100 coil.

 

[chrisshrops]

I went dyna works a treat

 

[The Other PaulG]

Thanks guys, brilliant advice as usual.

PG

 

[airhead_eire]

I think a 3 ohm Harley coil does the trick and is much cheaper.

 

[(RIP) Tibs]

How about for points ignition? Any suggestions?
(Dangerous thing to ask on here, I know!)
Tibs

 

[Garry H]

Harley coil or any of the old K series coils both are cheap as chips ...Much more reliable and fit on with a small adaptation
I have used both for loads of miles with no problems at all

 

[Beemerboff]

I have a Brown 3 ohm Dyna coil which I bought from a Harley dealer, they seem to sell them cheaper than BMW dealers.
Dyna coils are a superior product , according to Boyer - the best coils they have tested- but any 3 ohm twin coil should work in some fashion.- Most Jap lobster claw coils are 3 ohm, and wreckers in Oz sell two for a dollar.

Boyer now sell a small twin output coil at a sensible price, but I dont know the resistance, perhaps give them a call and find out if it will work.

 

[Deleted account 220427001]

got mine from motobins supposed to be for the dual plugging but I used it as the main coil does its job well cannot remember the price , fitted it to my r80rt ,good luck

 

[Belper phil]

Harley coil. Much more reliable and fit on with a small adaptation
I have used, with no problems at all

Agree with Garry - 1 fitted (HD coil) to my 80 GS - no problems at all so far and cheaper than standard BM

 

[The Other PaulG]

Update

Thanks again guys for all the great info - it well help others who might ask the same question in the future.

OK so....

I sourced a K100 coil (two, in fact, so if all goes well and you need my spare one, let me know).

The original coil has 2 connectors, one with a twin black wire and one with a single green wire (pic 1). This is exactly per the manual (pic 2) so it suggests I'm starting with a standard set-up. So far so good.

The K100 coil has three connections. The one on the left of pic 3 is marked '+' and '15'. The one on the right, facing the first, is marked '1'. The one at the bottom, between the other 2, has no marking. This is the coil that powered plugs 2 and 3, by the way, if that makes any difference.

Please, can anyone who has successfully carried out this conversion, tell me how to wire the existing R100GS loom to the K100 coil connections?

Thanks,

Paul G

 

[The Other PaulG]

BTW, I can see that common sense would suggest that I match up the 1 and 15 on the K100 coil with the 1 and 15 on the R100GS wiring diagram, but I don't know whether that 3rd connector needs to be incorporated / bridged too.

Garry H you mention a small adaptation, what is that?

Paul

 

[Beemerboff]

The extra black on your original coil goes to the rev counter, so if you connect 1 and 15 and the rev counter doesnt work you have the answer.

And if you dont have a rev counter and the bike runs ----------.

I have a spare rev counter, just been checked and serviced and includes a new housing, owes me around $A300- but they are asking EU500 for them on Ebay!

 

[The Other PaulG]

The extra black on your original coil goes to the rev counter, so if you connect 1 and 15 and the rev counter doesnt work you have the answer.

And if you dont have a rev counter and the bike runs ----------.

I have a spare rev counter, just been checked and serviced and includes a new housing, owes me around $A300- but they are asking EU500 for them on Ebay!

Thanks, but I was referring to the third connector on the K100 coil, rather than the third wire on the R100GS loom.

Can anyone definitively tell me what the correct connections are, and what the required modification is?

Thanks,

Paul

 

[The Other PaulG]

Anyone...?

Keen to progress this if possible.

 

[ianboydsnr]

Anyone...?

Keen to progress this if possible.

I am interested in the answer too,

Can you not just check the resistance between the terminals?

Then Just connect any of the terminals from the original bike to the two terminals that give the correct resistance, then ignoring the extra terminal, that's what I would do anyhow!

 

[The Other PaulG]

I am interested in the answer too,

Can you not just check the resistance between the terminals?

Then Just connect any of the terminals from the original bike to the two terminals that give the correct resistance, then ignoring the extra terminal, that's what I would do anyhow!

I made an assumption once before whilst sorting out the ignition on a jap bike.

The assumption seemed very logical, but was in fact incorrect.

So then I had a bike that still didn't work, and in trying the assumed fix, I was now unsure whether I'd now also goosed the cdi and other bits, that we're ok before I started...

Older and wiser, I've stopped making assumptions when there's someone who can tell you the facts!

 

[ianboydsnr]

I made an assumption once before whilst sorting out the ignition on a jap bike.

The assumption seemed very logical, but was in fact incorrect.

So then I had a bike that still didn't work, and in trying the assumed fix, I was now unsure whether I'd now also goosed the cdi and other bits, that we're ok before I started...

Older and wiser, I've stopped making assumptions when there's someone who can tell you the facts!

That maybe so, but the leads work on the original even if you swap leads around, therefore they are not polarity specific, finding the correct resistance of the terminals, tells you which of the 3 is used to fire the coil, I suspect the extra terminal to be just an extra place to fit a wire and will be connected to one of the other terminals,
That's not making assumptions, nor is it following heresay,

You can work out which to use by logic and a multimeter, which is probably how everyone else found out, when there were no one who knew what the answer was, or they asked but no one replied, the trouble with facts, is everyone's memory of them can be different,

Ian, must be lucky, as not very wise!