Harley Davidson Ignition Coil Problems

There’s a distinct spark of exhilaration that comes with firing up a Harley Davidson, the iconic rumble of its engine synonymous with freedom and the open road. But what happens when that spark begins to sputter? 

Ignition coil problems can snuff out your ride’s roar just as quickly as any major mechanical failure. Some of the common Harley Davidson ignition coil problems include burned ignition coil, vehicle sputtering, misfiring, and so on. 

Don’t worry, here, we will illuminate these common but often overlooked troubles, arming you with the knowledge you need to keep your ride running smoothly.

Harley Davidson ignition coil problems

Harley Davidson Ignition Coil Problems

After reviewing various forums and discussions featuring complaints from owners, we’ve discovered that these ignition coil issues are more commonly found in Harley Davidson motorcycles.

 Coils Keep Burning Out

A considerable number of Harley Davidson motorcycle owners have raised concerns about a recurring issue with their machines’ ignition coil. They’ve noted that it’s a frequent event where the ignition coil seems to continuously burn out.

It’s likely experiencing too much current which is causing it to burn out, indicating a deficiency in ohms on the primary side of the coil, which has low ohms. If you’re finding yourself in a bind, try using a ballast resistor from a car and place it between the coil and power source. 

Be mindful of the resistor’s size, if it’s too large, your spark will be weak; too small, and your coil will overheat. To create a spark tester, dismantle an old plug by removing its ground electrode. 

An ignition coil comprises two components: the primary and secondary parts – essentially coiled wires wrapped around an iron core. The ignition coil functions as a step-up transformer that converts low voltage into high voltage through fewer windings on the primary side and more windings on the secondary side. The only load borne by the secondary side comes from plug wires and spark plugs.

If there’s excessive current draw resulting in blown coils on the secondary side, this could be due to either plug wire shorted to ground or shorted plugs. You might also want to check out your cam sensor – if it appears melted, it can lead to no spark condition, which is a frequent issue with EVOs.

Now, if you’re using dual fire coils, ensure that your ignition setting is dual fire as well; single fire mode requires single fire coils – you can’t simply run dual fire mode with single fire coils. 

In case you have single fire coils installed, make sure not to mix up plug wires because this could cause improper functioning or complete failure of operation. However, with a dual-fire setup, plug-wire placement isn’t critical.

Bike Cranks But Doesn’t Turn Over

A myriad of Harley Davidson owners have lodged complaints regarding a persistent ignition coil problem. These riders described the issue as the motorcycle cranks but adamantly refused to turn over, promptly followed by a telltale odor of gasoline. This suggests that the spark plugs aren’t effectively firing as they should.

Many, in an attempt to remedy this problem, opted for replacing the spark plug only to encounter disappointing results; it didn’t rectify the ignition hitch. After careful evaluation, it appears that the main perpetrator behind this recurring trouble is surprisingly linked to the bike’s ignition coil.

Although most point towards this particular component, one can’t overlook that such a provocative issue might stem from several underlying factors compounding together over time.

Engine Stops Down the Road

It’s not unusual for a bike to stall in the middle of the road once a year, right? But imagine your Harley Davidson consistently breaking down within 40 km of every ride! It’s an absolute nightmare. Unfortunately, this is a reality for some Harley Davidson owners who have single-fire ignition coils installed in their bikes. 

If your bike has a single-fire system, it involves two coils that could either be contained in one case or be individual units. The issue might lie with the battery feed to these coils, which would explain why both plugs are not firing. It seems like there’s an issue with your coil. It likely lies with the power supply to the coil. Of course, there could also be an internal problem with a 2-into-1 coil. 

You can check this by placing your ohmmeter across the two input terminals (avoiding the plug-tower side). As stated above, you should find very low resistance indicating continuity but not a dead short or open circuit. Ensure there is power supply to the coil. 

You should also check the pick-up sensor. It’s unlikely that you’ll face issues with the coil on the plug side of things because each plug has its coil and neither is firing currently. 

If possible, borrow a known good stock coil and use only the front cylinder’s pulse wire for testing purposes in dual-fire mode while taping off others. Running it without timing cover won’t cause harm; if it stalls, then at least you can quickly cycle through the ignition switch and confirm uni.

Misfiring Engine

Owners of Harley-Davidson motorcycles frequently report issues with their engines misfiring, particularly at idle and low rpm. The bike’s performance can be inconsistent, with periods of normal operation interspersed with times when it seems to lack power. Additionally, a distinct change in the sound of the exhaust can be noticed. 

To diagnose this problem, you should inspect the coil for any signs of carbon tracking, which is an indication of arcing to the ground. This can appear as a thin line or crack on the coil housing that signifies misfiring. If you don’t encounter any difficulties during peak combustion pressures, your motorcycle likely has sufficient spark reserve while idling. 

Peak combustion pressures typically exert 50% more demand on the secondary loop which includes elements such as the coil (only its secondary side), wires, plugs, and plug gap

How to Test Harley Davidson Ignition Coil

The Harley Davidson ignition coil is primarily composed of two wire sets wound around an iron core. This component is pre-sealed and cannot be repaired. However, the testing process is quite simple, involving a couple of resistance measurements at the coil’s connection terminals. The procedure should not take more than 15 to 20 minutes. 

To begin, switch off the motorcycle and let the engine cool down before proceeding further. Next, manually disconnect the two spark plug wires from the coil and then unscrew the smaller connections on the coil using an SAE wrench.

Now, adjust your ohmmeter to measure resistance at Rx1. Check the resistance across both smaller terminals on the coil; it should fall between 2.5 and 3.1 ohms.

Next, change your ohmmeter setting to Rx1000 for measuring resistance across both larger terminals on the coil; it should register between 10,000 and 12,500 ohms.

If any measurement falls outside these ranges, it indicates that your ignition coil has malfunctioned and needs replacement.

One in the middle, one on the other side, that’ll give us our ohm reading and if one side is bad the coil is bad. A much easier way of testing your coil than electrocuting yourself on the side of your engine. 

Final Words

Owners of Harley Davidson motorcycles must be vigilant about the potential ignition coil problems that could affect their bikes’ performance. Misfires, engine backfires, and power loss are all common issues that stem from a faulty ignition coil. 

Regular maintenance and routine inspections can help to identify and rectify these problems early on, thereby preventing further damage to the motorcycle. It is recommended to consult professionals or authorized service centers for any repairs or replacements needed.

Leave a Comment