Vintage style horns and placement
 
The earliest Changs were virtually identical to the Soviet M72. That included the location for mounting the horn which was just aft of the hand shifter. Interestingly enough, I haven't seen any photos that would indicate R71s were built this way although some may have been.
Since most M72s had sidecars, it's difficult to find photos where you can see the horn. But on these solo bikes it's hard to miss.
One last M72.
When Gerald built Alpha he stayed true to all the vintage CJ/M72 details including placement of the horn.
There's a tab for mounting the horn welded to the frame as it should be.
On Grey Slowpoke I poked a small hole through the frame to accomodate a bolt. I really like the way this looks!
And here's where I put the horn on my black M1.
 
Which horn is best? The 6V Bailing (Lark) brand DL79-6 is perfect for mounting on the side of the bike. It's slightly thinner than the others and fits more flush. They're available from LRM.
This is a Bailing tag.
The 6V Shengjia (Fine Sound) DL38-6 is also a great looking horn. They too are available from LRM at very reasonable prices.
My favorite detail on the Shengjia is this metal tag which says bowl shaped electrical horn.
Here's the 6V Yingge (Parrot) brand, another version of the DL38-6. It varies only in appearance. These are also available from LRM.
The Yingge horn is made by the Hafei Postal Service Machinery Factory.
The 12V Yingge DL38-12.
This is a 12V Taiyang (Sun) brand DL126A. It was made in in Tianjin and is pretty similar in appearance to the Yingge horns.
DL-50 and DL-38-12 horns from the (literally translated) Shanghai Traffic Electrical Component Factory. (Clay Jones)
Another DL-50 from the Shanghai Traffic Electrical Component Factory.
This is a Russian 6V horn as often seen on M72s, K750s and the like.
This piece of crap came with my bike. It's especially ugly because it never worked. I don't know the manufacturer or model, but many Changs have these.
This is the loudest freakin' 6V horn I've ever heard. It's a Tuoling that Rich Hahn gave me. It's only about 3" in diameter—much more compact than the others.
If you can find one, this would be terrific mounted on the side of your Chang. It's a French-made Klaxon ETF4D, ca. 1968. It's from an old BMW and it's BIG.
Check out this old Russian horn. These can be found on Urals and Dneprs dating back quite a few years. You can still find them for $10!
Some neat old horns from eBay. The second one is from a Harley. The third is a Lucas.