FXDF Broken Bolt
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Novice
Joined: Jun 2009
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FXDF Broken Bolt
Hey all, let me premise this by stating I am fairly new rider and not a very mechanically inclined person, so if the following is a known or obvious issue, forgive me.
Just picked up my bike from the dealer for routine service. Apparently, one of the bolts that attaches the exhaust pipe to the engine was sheared off and the nut on the other bolt was about to fall off. Luckily, the dealer is great guy and only charged me a couple of bucks for new bolts/nuts (warranty expired last month). I only have about 15,000 miles on the bike.
Just wanted to throw this out there as something else to look for when inspecting your ride. Thanks in advance for all the great posts that have helped me on this site...
Just picked up my bike from the dealer for routine service. Apparently, one of the bolts that attaches the exhaust pipe to the engine was sheared off and the nut on the other bolt was about to fall off. Luckily, the dealer is great guy and only charged me a couple of bucks for new bolts/nuts (warranty expired last month). I only have about 15,000 miles on the bike.
Just wanted to throw this out there as something else to look for when inspecting your ride. Thanks in advance for all the great posts that have helped me on this site...
Ultimate HDF Member
Joined: Apr 2010
Posts: 7,138
Likes: 26
From: Southern Oregon
When working on a harley loctite is your best friend. get a service manual, it lists the maintenance schedule and what all should be checked at each interval. Justs keep a close eye on things in between.
Road Captain
Joined: Nov 2009
Posts: 717
Likes: 0
From: California
Bolted joints can fail in multiple ways.
One example is tensile failure. This usually happens if you over-torque the fastener and exceeded the material yield strength. The bolt would elongate and perhaps eventually reach the materials ultimate strength, which causes catastrophic failure. Of course the elongation alone may cause failure as well due to reduced clamping forces. This is why it is advised to torque fasteners to their recommended specifications.
Another example is thread shear, were the threads strip off the shank. This usually occurs when a bolt that is too short is used, only allowing 1-3 threads of engagement. The stresses are too great for the small amount of material in contact, and failure can occur.
A third example is shank shear. This occurs when the lateral forces applied to the bolt are too great, the material yields, and the bolt is sheared in two.
Its tough to say what your situation was without seeing the bolt and mating area. Since your sig shows what looks like a stock exhaust, it may have been over-torqued at the factory, or perhaps just a bad bolt (bad raw material).
Im glad you found a dealer that addressed the problem and didnt charge an arm and a leg to get it repaired. Ride safe, and thanks for sharing.
One example is tensile failure. This usually happens if you over-torque the fastener and exceeded the material yield strength. The bolt would elongate and perhaps eventually reach the materials ultimate strength, which causes catastrophic failure. Of course the elongation alone may cause failure as well due to reduced clamping forces. This is why it is advised to torque fasteners to their recommended specifications.
Another example is thread shear, were the threads strip off the shank. This usually occurs when a bolt that is too short is used, only allowing 1-3 threads of engagement. The stresses are too great for the small amount of material in contact, and failure can occur.
A third example is shank shear. This occurs when the lateral forces applied to the bolt are too great, the material yields, and the bolt is sheared in two.
Its tough to say what your situation was without seeing the bolt and mating area. Since your sig shows what looks like a stock exhaust, it may have been over-torqued at the factory, or perhaps just a bad bolt (bad raw material).
Im glad you found a dealer that addressed the problem and didnt charge an arm and a leg to get it repaired. Ride safe, and thanks for sharing.
Seasoned HDF Member
Joined: Jul 2008
Posts: 9,282
Likes: 1,139
From: southeast PA
When inspecting your bike, check all your bolts and fittings, shocks, spokes, drive belt, exhaust and heat shields, etc. A good time to do this is when washing it. You don't have to look at every single engine case bolt but things like sprocket bolts, shock mounts and exhaust hangers get a lot of stress. It also helps you get familiar with your bike. Anytime you find something loose it will have been worth your time.
Road Master
Joined: Apr 2009
Posts: 750
Likes: 3
From: 3rd Rock
Hello All,
Another example to stress the inportance of using a torque wrench. The local HD service Dept. Hour-glassed one of my hedder studs once. They pointed it out somr time later and, made it good. I pointed out to them that if they had use a torque wrench, that probably wouldn't have happened. Insist that your mechanic use them!! And don't use loctite on the exhaust studs, could be you wouldn't like the outcome.
Glad it worked out for ya. Tim
Another example to stress the inportance of using a torque wrench. The local HD service Dept. Hour-glassed one of my hedder studs once. They pointed it out somr time later and, made it good. I pointed out to them that if they had use a torque wrench, that probably wouldn't have happened. Insist that your mechanic use them!! And don't use loctite on the exhaust studs, could be you wouldn't like the outcome.
Glad it worked out for ya. Tim
Seasoned HDF Member
Joined: Dec 2010
Posts: 7,736
Likes: 1,524
From: Coromandel Peninsula New Zealand
Exhaust studs are little monsters....I find that everytime I replace an exhaust gasket on a Harley it usually needs a good run and re-tightening 3 times, after the 3rd time they stay where they are....I always have 1/4 drive 1/2 inch socket on board...
Seasoned HDF Member
Joined: Jul 2008
Posts: 9,282
Likes: 1,139
From: southeast PA
After the second tightening I double nut the studs. No more worries about those buggers.
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