I want a louder horn

That little "beep, beep" of the OEM horn, IF heard by anyone, only makes them look around for a clown car. Since you're not in a clown car, and you want people to acknowledge your presence, a better horn is in order.

You can get a LOUD FIAMM horn for about $15 at a regular car-parts store (e.g. O'Reilly, Advance Auto Parts, etc.) Places on eBay have them, as well as JC Whitney and ridesafer.com.

Get the low-tone; The 125 dB AM80 is probably your best bet. It's the one used by the majority of club members. They're way louder, and are a bolt-in replacement for the stock horn. Point the bell of the trumpet down so it doesn't collect water, and cover your ears before you test it in an enclosed space. Even with it pointing down, it is loud and can be heard by cars and other motorcycles easily.

Avoid the FIAMM piezoelectric horn (looks like the stock one, or a small speaker). They're smaller, and look like they'd fit better, but they're not as loud. Get one of the trumpet-shaped ones instead.

The low-tone horn is still relatively high-toned. It cuts through noise quite well. The difference is that when people hear a deep horn, they get more of that instinctive "Oh crap, what's going to smoosh me?" feeling. You want them to have the feeling that they're impinging on your space. It seems to produce a more pronounced effect than the high-tone horn. When you hear that low-tone horn, you look around for the big Cadillac that's about to turn your car into junkyard art.

Some members tried the high-tone horn, on the theory that people would be looking for a bike if they heard a high horn, but it didn't seem to work out in practice. The low-tone horn brings much better results. It sounds more like a semi than the high-tone.

It's a direct replacement. No relay is necessary. It includes a bracket for mounting. Installation time is estimated at "120 seconds".

A couple things to remember: The horn on the EX250 is "always hot" (meaning it always has 12V supplied). The horn button grounds it. Also, don't forget that the EX250 frame is also grounded. So, if the horn body is connected to its terminals, you need to isolate the horn body. This is one reason why the stock horn is mounted on a rubber insulator.

The top picture shows the stock horn on a naked bike. The bottom picture shows the new horn installed on a bike with a fairing.