Honda doesn't make batteries; they have their name put on a battery made by another company. (My bike has and AGM battery with a Honda logo on it. Maybe I'll post a picture after I go in to hook up my Gonzo wire harness.)
The stock battery on Honda's VT1100 bikes (and VT750 too?) is a T-shaped battery. AGM batteries could be built in the T-shape, maybe some are. But Honda uses a "flooded-cell" (or "wet cell") -- one that has liquid splashing around and is vented to the atmosphere. This technology goes back a long way-- 100 years or more.
AGM stands for "A
at" and is much newer technology. AGM batteries rely on the same chemistry as flooded cell batteries and, while not "flooded", are still wet-cell batteries. But they don't have the liquid splashing around. An AGM will generally last a LOT longer than a flooded call battery and would be considered "maintenance free" because you do not need to keep tabs of the level of the liquid.
There are also gel batteries and some folks (including me once upon a time) had these confused with AGMs.
You can get much, much more info here
ifyou are interested.
Based on my experience with my bike, I will NEVER have a T-shaped battery in it again. I will NEVER have a flooded-cell battery in it again. The flooded-cell T batteries are hit or miss, mostly miss; I went through 3 in the first 5 years I had my bike. Until better technology comes along at a comparable price, I'll stick with AGM.
To your specific problem:
- Remove the battery from the bike and check the fluid level in all the cells. Add distilled
water to any that are below the marks. This can NOT be done on the bike.
- While the battery is off the bike, hook it up to a slow charger and get it fully charged.
- When the battery is fully charged, take it somewhere and have it tested. If it fails (as I suspect it will), take it back to the dealer (with receipts) and raise a fuss. If it passes, you've got to spend some time checking out your charging system.
Generally, the charging system on Honda's VT1100 bikes doesn't put out a lot at idle -- so your horn troubles while stopped are an indication of a battery issue. If you have the same issue while cruising then something else *might*
be causing trouble. Focus on the battery first, though, since it is the thing you changed.