Join Date: May 2007
Location: Central Illinois
I spoke with a technician at Wolo Manufacturing regarding the model 419 that I have on my bike. It looks like, and possibly is, the exact same design as the Stebel Nautilus Air Horn.
He said that the problem of the horn failing to sound properly is due to the diaphrams becoming clogged with dirt and debris. The diaphram(s) are under the round plastic discs that fit loosely on each side of the model 419. To clean the diaphrams, pop of each of these discs(I assume you can use your hand) and use an air hose with blower attachment to blow in to the small holes located there. Might want to sound the horn with these plastic caps off while tapping on the side of the horn with a rubber mallet.
The other thing he recommended was to tap on the clogged sound chamber(s) with a rubber mallet while sounding the horn to help break free the dirt and hopefully blow it out of the sound openings. You should actually try this method first before trying the remove the diaphram caps method.
Do not spray any kind of cleaner or lubricant into any part of the horn. It is not needed and may only clog it worse.
If you ride in dirt more often, the 419 will clog more quickly, particularly if it exposed. Amazon.com sells the model 419 and a new motorcyle horn, the model 619, more cheaply than they can be bought on the Wolo website. These horns are said to have been re-designed to deal with this problem, but I don't see much difference in the pictures of the 419. However, the diaphram openings of the 619 are on the side and look much different. The 619 is said to be louder, also. It might be less apt to clog than the 419, but I'm not sure.
Don't bother trying to get a replacement from Wolo if the horn is more than 90 days old. They won't do it.