How To Repair a Harley-Davidson With Loose Pulley Bolts

If you’re reading this article, we’re sorry; presumably you've just suffered a close call and your pulley fasteners are to blame. We hope you’re okay, and we also hope your bike wasn’t damaged—neither of which are guaranteed to be true, unfortunately.

So now you’re looking to prevent this problem from reoccurring in the future. The issue is a nuanced one, but the instinctive solution—snug the bolts up and move on with life—is not the correct one. Your repair should break down into three stages: assessment, planning, and prevention.

Assessment

If the bolts backed out, damage probably occurred, and determining the extent is Job One. A wrecked pulley and damaged swingarm are obvious but often if the damage doesn’t appear to be massive, many riders are tempted to put the wheel right back into play. Don’t! You need to examine the pulley threads very, very carefully. The threads are often damaged when the pulley bolts loosen and become ovoid (“egged out”). Sometimes thread repair is possible, but often, a new wheel needs to be procured. Make sure you make an informed decision.

After you really scrutinize the female threads, examine the flange where the pulley seats. All too often, loose fasteners cause damage to the mating surfaces. Maximum surface contact is what you want, and damage destroys that. A kiss with an endmill might be enough to repair a wheel—or it might not. Same goes for the pulley. Also examine the machined area for the bolts on the pulley; this is also a place where you don’t want reduced surface area contact. It’s highly likely your pulley was damaged, and if it was, now is not the time to reinstall it—the prudent option is pulley replacement. 

Be aware that Harley used studs and nuts on some wheels, too—that requires different assessment. Most studs are a bit more immune to the loosening that bolts are plagued with. 

After all of that, you’ll also want to ensure the wheel is still cosmetically attractive and also check how the wheel spins—an off-kilter sprocket driving a wheel for a short time is often all it takes to wipe out a bearing or two.

Planning

Now, you need to come up with a plan of attack for your repair. You may want to follow the service manual exactly, or you may wind up deviating. However, being aware of what the MoCo intended is probably a safe jumping-off point, but be warned: Harley-Davidson changed pulley bolt torque specifications over the years, changed replacement recommendations for the bolts, and changed recommendations regarding use of a thread locking agent. Whether or not you elect to follow the service manual’s recommendations is certainly up to you, but erring on the side of caution might make sense.

You probably aren’t hurting anything by treating the bolts as one-time-use-only. Many years and models specify as much in the service manual, and replacing hardware each time doesn’t hurt anything. We offer replacement hardware (like this set for alloy wheels), and Colony, the manufacturer, recommends replacement any time the fasteners are disturbed, regardless of what the manual says, and we agree—that’s the safer option given the modest cost of the fasteners.

Thread locking chemicals are a matter of personal choice if disregarding the factory service manual, but many riders elect to use them since the factory did indeed call for one of a few different thread locking substances to be used on many motorcycles. You may also find that some riders think the factory-recommended quantity was a bit skimpy, so don’t be surprised to see some bolts getting real healthy doses of these compounds.

Finally, there are a number of mechanical locks on the market. We’re fond of our pulley bolt lock because they’re affordable and they don’t require the use of any special hardware. Other riders have found great success with complete systems like the ones offered by Hugh’s Handbuilt. You’d have a hard time going wrong with either one since both mechanical lock setups are added insurance above and beyond what Harley-Davidson used from the factory.

If you’ve got a stud-and-nut arrangement, you may want to weigh removal of the studs; steel studs are often used when damage to the parent material (the aluminum hub) is likely, so many mechanics feel disturbing the studs does more harm than good. 

Prevention

As a parting note, it’s likely you’ll keep a close eye on this area of your bike, but we can help make this easy in the future with a quick tip: Make an indexing mark on your bolt heads and pulley. Using a paint pen, draw a line from the bolt head onto the pulley so you can make a quick visual check each time you approach your bike.