Coil replacement

[ThatXS650Guy]

Hey Gang, I have been working on the 79 Special little by little and have been taking it out for short trips around the house. It's a really fun bike to ride. The problem is I have come home a few time son just one cylinder. The right side cuts out after a short while. When I limp home and test for spark there is none but if I go back after it cools down it sparks up fine and runs as if nothing happened. Classic coil going bad symptoms, right?
My question is if I am going to replace the one coil should I go ahead and upgrade? A new coil is around $40 and I was looking at the ignition kits on Mike's for $142 or so. Worth the money? That kit also replaces the points, correct? What else would I need or is everything in the kit?
TIA,
Jim

 

[figure8]

Yes, sounds like a coil going bad. A Pamco is a solid investment and you have great tech support right here in the forum.

 

[fredintoon]

Hi Jim,
there's two separate decisions trees here.
First tree:-
Should you replace that coil? Yes.
The both of them? Again I'd say yes.
Should you get hotter coils instead of straight replacements? Yes once more.
Second tree:-
Should you upgrade from points or from points & mechanical advancer with the appropriate Pamco?
You decide.

 

[5twins]

You need at least one coil anyway. I would put that money towards the Pamco upgrade, you won't be sorry. I don't think I'd go for that basic kit. I'm pretty sure there have been problems with the wire terminals pulling out on that basic coil. It also has the plug wires molded in so you couldn't easily replace them in the future if need be. A step up to the $170 kit would probably be better.

But, we're lucky in that we can use Harley coils , and they're a dime a dozen on eBay. I would get the basic ignition only kit for about $100 and buy a coil separate. All you need look for is one with about 3 ohms primary output, something like this .....

http://www.ebay.com/itm/Harley-COIL...ash=item46427253ac:g:g2kAAOxyVLNSuJlM&vxp=mtr

If you shop around, you can find nice used brand name ones for even less. Over the last few years, I scored a nice Accel for $15 and an Andrews for $25.

 

[RFeng]

I've replaced with new original style coils on my 77 and 79. Stayed with the points on all three bikes. Clean and adjust every now and then, check timing etc. is just part of my experience having fun with old bikes
Pamco looks great, but I understand points and coils.

bruce

 

[XS650D]

Guys i have a coil related question on my 77.Do the replacement coils that Mikes sells equal
the original stuff,they sure look the same.I have discovered a lot off corrosion on the inside off one off my coils,guess the seal wasent sealing so am thinking off just getting a duplicate replacement set same as stock.Never had any problems starting with current original system.I just use kicker from cold and electric when warm.Does anyone know if the wires Mikes sells are as good as the originals,may as well replace them also.

 

[TwoManyXS1Bs]

A concern on new/replacement points coils is the mounting studs.

The OEM factory coil studs have a shoulder, just slightly proud of the plastic body. This shoulder makes a good physical/thermal contact on the topside of the mount plate, and tightening tension is confined between that shoulder and the nut.

The replacement coils I've seen don't have that shoulder. That means that tightening tension occurs between that nut and whatever stud fitment scheme exists inside the coil body...

 

[XS650D]

Thx Too Many! Will do a lil sanding with Dielectric grease when i change them out,Good info .Ps: guess Mikes dident reproduce the original stuff to spec,guess im not surprised!!

 

[5twins]

With so many people doing the Pamco upgrade, there's bound to be a ton of good old used stock coils out there. Yes, some old electrical components crap out but some last darn near forever. This was a very common coil used on many Yamaha models. When I put my 650 together, I had a box full of about a half dozen to choose from. I tested them and picked a couple good ones (yes, there were some bad ones), and they served me faithfully for the 1st few years until my Pamco came along. Even today I don't think I'd consider buying new repros. Like I said, too many good old ones available cheap.

 

[ThatXS650Guy]

But, we're lucky in that we can use Harley coils , and they're a dime a dozen on eBay. I would get the basic ignition only kit for about $100 and buy a coil separate. All you need look for is one with about 3 ohms primary output, something like this .....

http://www.ebay.com/itm/Harley-COIL...ash=item46427253ac:g:g2kAAOxyVLNSuJlM&vxp=mtr

If you shop around, you can find nice used brand name ones for even less. Over the last few years, I scored a nice Accel for $15 and an Andrews for $25.

I think this might be the way to go. Thanks 5twins.
And thanks as well to everyone else who responded.

 

[Wingedwheel]

I picked up a pair of the oil filled coils from 650 Central. You have to drill a new hole on the mounting plate but it was easy and my spark output is much higher, plus they are only a few dollars more than stock.

 

[XS650D]

Got my new Mikes original replica coils and some new "blue" 7mil silicone wires (thx 5 twins) installed today.Had to sand the bottom attachment plate as per above post for a good ground and went for a ride .Were gettin a warm spell.Bike ran better than it ever has.Its just gettin smoother and smoother.Everybody luvs this old bike,lots off looks and questions,just makes the experience off owning one that much sweeter!

 

[ThatXS650Guy]

I ended up getting a Mike's Ultimate coil on eBay and the basic Pamco. Installed this past weekend but I have not done the timing yet.
I had to fab up a mount because I wanted to use my almost new plug wires. I only had to "modify" the tank a little with a ball peen.

The plates I made will be cleaned up and painted.

 

[pamcopete]

I ended up getting a Mike's Ultimate coil on eBay and the basic Pamco. Installed this past weekend but I have not done the timing yet.
I had to fab up a mount because I wanted to use my almost new plug wires. I only had to "modify" the tank a little with a ball peen.

The plates I made will be cleaned up and painted.

Are those vintage spark plug wires rated for an electronic ignition? The voltage from an electronic ignition, especially the "Ultimate" coil, is at least 5 times greater than from a points setup with a points coil. It will arc right through the fabric of traditional vintage wires to the gas tank or any other nearby metal.

Here is a video of a PAMCO and the "Ultimate" coil output jumping a 1" gap:

 

[ThatXS650Guy]

Nah. They just look vintage.
"This is plastic coated woven cotton over pvc with a solid copper core wire"
No issues with arcing but I'll be on the lookout. Thanks.
Pretty excited about the Pamco BTW.

 

[ThatXS650Guy]

Question. With the High Output coil should I open up the spark plug gap?

 

[pamcopete]

Question. With the High Output coil should I open up the spark plug gap?

You can. It might mean a little better performance and gas mileage because that exposes more of the mixture to the spark which produces a bigger "kernel" of flame to more completely burn the rest of the mixture. Kinda like lighting the camp fire with a bigger match.

Try .035 .

 

[mickeysolis]

this is an old thread obvi, but

what increase is suggested? for the high output coil: 17-6803

 

[pamcopete]

Use a kit with the 17-6903 coil. 6-9-0-3, not 6-8-0-3.

 

[mickeysolis]

Aha!
So if i have a 6-*8*-0-3 from Mike's should i leave the plug gap alone, or do suggest i just get the 6-*9*-0-3 and increase to the .035 range?

I'm having spark failures right now after installing the basic pamco and hugh's pma. '81 Hspecial (cdi swap) Ran great for a week, then all the sudden a dead battery. After the battery was replaced, no start. Seems to be erratic/no spark on the left side
Think the problem is in my wiring job (i'm a real newbie) but the end result is a coil that's testing well above the 15-20 range at 200k on the tester.
Planning to replace the coil and rewire the whole system but i'm also having trouble finding a bare bones wiring diagram for a PMA+Pamco system that includes a battery (*not* a capacitor), the stock turn key, and a solenoid for the starter with a momentary push button. Beyond that it's only head and tail lights.
Sorry, I'm realizing this is actually TWO separate (but related) issues i've gotten into, but you're the man, Pete, so I'm trying to get a direction while i think you're still there....
Thanks