Poor Design - Horn Mount
#1
Poor Design - Horn Mount
Just back from flying a 1,800+ mile turn 'n burn of the Blue Ridge Parkway. As I stopped at a stop sign about 2 miles from my crib (just exited the E-Way), it sounded like my top end was coming apart! Glancing at the left side of the mill, I see my horn vibrating against the cylinder heads!
Landing at home port, I docked it in its berth and let it cool down while off-loading stuff/starting laundry. Figured I'd examine it after the mill got down to a reasonable temp. I'd just flown a 533 mile hop in 8 hours, so the mill was a mite warm!
In summary, there is a circular bracket that holds the horn in place. Harley's design has a circular rubber piece mounted inside the bracket with a large headed bolt, the size of the bracket (apparently) glued to each side of the rubber mount. My rubber piece separated in the middle, allowing the horn to fall off. Half the rubber remained in the bracket, half fell off. All bolts intact. The replacement part is $6.00 from a stealer.
I inquired of the parts manager is this was a common failure. He told me they had experienced a few. This was a stealer near my duty station the next day, not the one I regularly use when I need parts. Its a newer stealership, so I'm not sure about the data I got from them.
I'm thinking the new part will undergo serious modification before installation! First, the rubber will be drilled out to accommodate a full length bolt, then metal washers milled to size to fit over the rubber, but within the bracket. That should preclude another event. I'll make a mock up with the old part/test before going final.
Given the amount of cavitation the horn gets, I'm very disappointed in The Motor Company's design. Near as I can tell, there is no way to anticipate this failure.
Meathook: out
Landing at home port, I docked it in its berth and let it cool down while off-loading stuff/starting laundry. Figured I'd examine it after the mill got down to a reasonable temp. I'd just flown a 533 mile hop in 8 hours, so the mill was a mite warm!
In summary, there is a circular bracket that holds the horn in place. Harley's design has a circular rubber piece mounted inside the bracket with a large headed bolt, the size of the bracket (apparently) glued to each side of the rubber mount. My rubber piece separated in the middle, allowing the horn to fall off. Half the rubber remained in the bracket, half fell off. All bolts intact. The replacement part is $6.00 from a stealer.
I inquired of the parts manager is this was a common failure. He told me they had experienced a few. This was a stealer near my duty station the next day, not the one I regularly use when I need parts. Its a newer stealership, so I'm not sure about the data I got from them.
I'm thinking the new part will undergo serious modification before installation! First, the rubber will be drilled out to accommodate a full length bolt, then metal washers milled to size to fit over the rubber, but within the bracket. That should preclude another event. I'll make a mock up with the old part/test before going final.
Given the amount of cavitation the horn gets, I'm very disappointed in The Motor Company's design. Near as I can tell, there is no way to anticipate this failure.
Meathook: out
#3
Don't know how old your bike is,but those horn rubbers have been used for years and years,they will break,like anything else. The old design had a softer rubber,and a rubber bumper near the bottom front and rear.Those lower bumpers actually 'bumped' against the cylinders.
What you are planning to do will work. I've mounted a horn solid one time-[no rubber] and that didn't last long at all.The metal bracket broke!
What you are planning to do will work. I've mounted a horn solid one time-[no rubber] and that didn't last long at all.The metal bracket broke!
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"Cavitation is the formation of vapour cavities in a liquid – i.e. small liquid-free zones ("bubbles" or "voids") – that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low. When subjected to higher pressure, the voids implode and can generate an intense shockwave." - Wikipedia
It gets vibration and that's why it is rubber mounted. If your fix is a rigid mount don't expect it to last anywhere near the stock mount.