H-D Forums Asks: Why Are My Milwaukee Eight Spark Plugs Loose?
If your bike isn’t running as it should, the fix could be simple.
The Harley-Davidson Milwaukee Eight engine is an engineering triumph. If offers impressive performance and has been collecting accolades from the motorcycling press since it was introduced.
However, even the best engines in the world have a few unusual quirks. Apparently, one of the Milwaukee Eight’s quirks is loose spark plugs from the factory.
The issue is covered at length in our forums. Deckdr posted a thread recently, and several members have chimed in to say that they, too, have found loose plugs on their Milwaukee Eight-powered Harleys.
How Do I Check My Plugs?
Like any good discussion, this spurred a tangent about ease of maintenance. A few members are understandably upset about having spark plugs mounted under the fuel tank. Another member, 19special, sets the record straight.
Removing a fuel tank to check plugs may offer a challenge to some hobbyists, but overall it’s not too difficult or time-consuming. Removing the tank involves 4 bolts, a quick connect fuel line, a couple electrical plugs, and a vent tube or two. Not too bad for some peace of mind.
Other members chime in and offer advice for protecting the paint and draining fuel first. As always, H-D Forums is a great source for tips and advice like this.
However, the argument can and should be made that folks with new bikes shouldn’t have to check for spark plug tightness of all things. Some posters say that their plugs — especially the two underneath the fuel tank — were only finger-tight.
In addition to rough running and poor fuel economy, loose plugs can also damage the threads in the head. That can lead to a costly repair.
We hope that this article hasn’t caused you any undue anxiety. After all, Harleys should be relaxing, not stressful. If it makes you feel any better, many members have stated that their spark plugs were tight enough from the factory.
However, if you do feel inclined to check them, we hope that this post can help. One last thing — if you feel overwhelmed by any job on your bike, there’s no shame in taking it to the dealer.
Photos: Harley-Davidson
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