Yer Batter is showing classic Failure signs... charges fast to at least 13v...but won't hold under load...Ours were suffering from being OverCharged when they failed like that.
But, again...it is a classic sign of Failure...and not always in Extreme service..
What is the voltage [accross the battery terminal with a digital VOM] when you push the start Button???

 

Finally after 5 or 6 years of himing and hawing and phoning Daniel at Frankenstein trikes asking questions, also asking the forums every type of question I could think of I ordered my kit from Frankenstein. It came faster than expected and went on quickly because of a excellent install manual. This kit also came with Vance and Hines short shots and I got the optional quiet baffles. So yesterday I went down to my local insurance company to insure my new trike only to find out I have to get a government approved inspection and change the registration to a modified bike. Well I phoned the inspection place only to find out my exhaust had to register 92 decibels or below before it would pass. What I did was find an old pair of sportster mufflers , cut them apart and modified the baffles I took out of them to fit inside the optional quiet baffles. I also stuffed some of the baffling I got out of the old mufflers. After hours of cussing Our Canadian government, cutting the modified baffles over and over I think I have got them quiet enough to pass inspection. I just hope the inspection place doesn't need to have the stamp of approval that was on the stock pipes. If they do I will be cussing again. I hope all you lucky Americans appreciate the freedoms you have and don't have to live in a almost dictator ship country like us Canadians do

 

Nice ride. Glad to see chrome is still alive. My '11 XL1200C looks similar.

 

Our laws down here vary from state to state. CA is one of the worst. Currently no smog inspection on bikes, but no idea what a "modified" bike would be like. Not really sure if we have that, but let our bureaucratic morons hear about it and I am sure we will. Any new "fee" is money in their crooked pockets.

 

I've had a couple bike and at least 2 car batteries act similar, good voltage, hit the starter and immediately drop in the 7 to 9V range, but charge back up quick. And keep doing the same thing, never getting better. From what I've read about it, sulfation is the likely culprit. In its extreme, sulfation bridges the gap between plates and shorts them out, according to some opinions. I have had 2 or 3 batteries go from working good to completely dead just minutes after the vehicle had been running fine, and that's not a normal wear pattern for a battery, I'm guessing they shorted internally somehow. Those wouldn't take any kind of charge afterwards, either. I tried some cheaper batteries for a couple years, figured if they go bad I'll just jump them with a little lithium jumper I can easily carry. So the first time I needed it, nothing, I found out the hard way they won't jump a shorted battery. I'm 72, might be a little moldy in spots if I checked...

 

@gerald martin I converted a Sportster for my partner. We have similar but the registration changes from motorcycle to motor tricycle. As a bolt on kit and not directly modifying the frame the vehicle only has to go for
Ministry Of Transport (MOT) test that all vehicles have yearly. If the frame were modified it becomes a one off vehicle and has to have a Motorcycle Single Vehicle Approval test.

Exhaust "noise" is subjective and down to the MOT tester.

 

I'm considering a new jacket. Snaps or zipper?

 

I hadn't heard from one of my riding buddies for several months and I knew he has a history of heart problems. He usually rides his 99 Road King past my house when he goes for a ride and I haven't seen (or heard) his bike go by and was concerned. I finally saw him yesterday and he told me that his heart problems flared up and after spending 3 months in ICU and an additional 3 months in house arrest, his doctor had ordered him not to ride his motorcycle. Finally, he has the go-ahead to ride and after he and I finished talking about his health, the first thing we talked about was our next ride. Next week, the temp is supposed to climb all the way up to 60 degrees with no precipitation. Yep, we're goin' for a ride!!!!! Road King and Sportster. He's tall and I'm short. We look like the old dog food commercial for Kibbles & Bits. We have a great time riding our very different bikes with mutual respect for each other and we are both senior citizens who like casual touring through the mountain twisties.

 

I was thinking Mutt and Jeff

And for Sportster content, I thought I had a bad battery on my 06 Sporty because the bike wouldn't start in the cold so I bought another. When I went to do the swap I decided to take it to the Indy to have it tested and the old battery is fine. Cleaned up the connections and it fired right up with temps in the 30's. Will have to see how it does tonight since we've had several nights below 20

 

I guess I've been lucky over the years. I've been using my Battery Tender Plus (for wet cell and AGM batteries) on my car, motorcycle and mower batteries for close to 20 years and it has always charged all of them with no problems. It has paid for itself many times over by extending the life of all my batteries which go into storage. I only use the one unit and I rotate the lead to the pigtail from one battery to the next each week. I have pigtail on each battery, as well as short and long extensions cords for the Battery Tender.

When I buy a new battery I always hook it up to the Battery Tender for a full charge before I install it into the vehicle. So far, no problems and it is the only Battery Tender I've ever owned.

On a different note, the only battery problem I've ever experienced was with an Optima Yellow car battery which would not keep a charge. After researching the battery online, I found out the company had been bought out by another one which had shoddy quality control. Optima's reputation dive-bombed after that. Fortunately, Advance Auto gave me a full refund after I had been fighting the battery for six months.