When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
The coil i see is a 3 ohm you should check it - the dyna ignition ONLY takes a 5 OHM coil for street riding - if you have used a 3 ohm with at dyna as little as a day the dyna has burned out
the sporty take headlight ring off and see if the circuit breakers are in the HL - or in front of the rear fender - no pictures or info about what year so its a guess
iso the breaker clicking out see what works then - what does not work is your issue
It's a 1979 FXE (in the original post). The new 5 ohm coil from Amazon is producing spark in both cylinders, which I think means it's fixed, for now. Haven't ridden it yet since we've had rain since yesterday, though.
The bike came to me a month ago, and now that it's other issues (e.g., clutch release) have been fixed, I've ridden the bike probably 100 miles with the coil pictured above. I'm assuming the previous owner was using that coil as well. They make 5 ohm coils with this OEM-style case, so it's hard to know whether it really was 3 ohm or 5 ohm.
@johnjzjz Now that I've changed coils I'm getting spark back in both cylinders. Would you say this rules out the old coil having been 3 ohm, since the dyna ignition is producing spark with a new coil? Or are there other things I need to check to see if the dyna has been damaged in some way?
Last edited by adam3131; Feb 12, 2023 at 02:14 PM.
As I said earlier with a Dyna S they either work or don't, no in between or sometimes with them. You got spark then it's time to move on to timing and the intake system. Intake leaks are next most common problem to deal with.
Just an FYI, couple of us in here are old pro's, there's probably well over 80 years combined experience between John & I, John is still a long time shop owner dealing with old iron. Advice we give isn't limited to a bike or two or second hand.
@TwiZted Biker Ive been benefiting from both you and Johns posts (among others) for years before becoming active on here more recently. I know firsthand how knowledgeable you guys are, and truly appreciate that hard-earned experience is being shared with the rest of us on the forums
In his most recent reply, John seemed to have a different opinion on whether 5 ohm and 3 ohm coils are equally interchangeable when using the dyna s.
Sounds like you both agree 5 ohm is the first choice (as does the Dyna instruction manual), but if theres a possibility that the coil I just replaced was 3 ohm, Johns last post indicates that a 3 ohm coil could have been less than ideal for the dyna.
Was asking if he thinks I have anything to be concerned about the health of my dyna moving forward mainly so I know how far from the garage my first couple of test rides should be, and whether to blame the cheap-o coil I bought on Amazon if something craps out.
3 ohm with a Dyna-S is for race applications meaning short high intensity runs not long duration like daily riding. Can't give the science behind it as I've never raced them but I have seen the stock 3 ohm coils burn out the Dyna units on daily riders. Long as the ohm check on the coil reads anywhere close ( 4.5 to 5.5, I've seen them all over this range ) they should work meaning they make enough spark for the heat range plugs you run. What spark plugs you using ?
I switched the champions that the previous owner was running to NGK BPR5ES, which it seems to like.
In fact I was pretty impressed with how strong it was running after fixing the clutch, flushing the tranny with kerosene, and putting fresh fluids in transmission/motor. After a few successful shakedown rides, I started really ripping it on the most recent two rides before the coil gave out.
Strangely the coil didn't fail while I was riding it-- I got home, parked it outside the shed, and installed an FNA tite seal kit because it was beginning to develop an intake leak once warmed up. After installing the new FNA intake seals I tried to start it up and only got spark to the rear cylinder.
What I really should do is just test the resistance of the old coil to find out if it was 5 ohm or 3 ohm-- that is, if it'll still give a reading now that it's broken. But as you've advised, it probably doesn't matter since I'm getting spark to the plugs with the new coil. Based on the above I'm assuming that means the ignition is fine.
Its a long un necessary explain for the 3 verses the 5 with that type dyna short version use a 5 with the dyna s always
is it ok now yes its a switching magnet pole breaker of sorts it trigger going into the magnet in the center and triggers out as it passes the trigger both cylinders
if you have spark your good to go
the intake - its a flat ring intake maybe 79 FXE if so you want to use the red silicone rubber bands only and aircraft clamps they call them - and hylomar on the inside and some on the out side will hold the clamps in place so they dont slide around in a few rides
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Slideshow: The bar-and-shield logo shows up on far more than motorcycles, some of the company's most unexpected products have nothing to do with riding.
Slideshow: From the troubled AMF years to modern misfires, these bikes earned reputations for reliability issues, questionable engineering, or disappointing performance.
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Slideshow: The Swiss custom shop has taken a Harley Softail and stretched it into something so long and low that it looks closer to a rolling sculpture than a conventional motorcycle.
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Slideshow: A standard cruiser becomes an intricate metal canvas in the hands of a Swiss custom house known for pushing Harley-Davidson platforms far beyond their factory brief.
Slideshow: Harley-Davidson's challenges aren't abstract; they show up in dropping shipments, shrinking dealer traffic, and strategic decisions that aren't yet translating into growth.
