xs400 maxim 82, battery/ general issues.

Hi, I was hoping I could get some input from someone here about battery issues. My maxim came with an battery of unknown age that matches the specs of the yuasa lead acid battery I see recommended on this forum and I bought the Mighty Max AGM YB12A-A . The old battery starts the bike fine, but the mighty max just doesn't provide enough power. I've charged both, the old one goes flat after a bit but fresh it can start the bike. It seems like at rest the mighty max is about 12.2 and the old battery is about 12.6, does anyone know if that's just how the mighty max agm battery is and I have to use a lead acid or did I get a dud?

I have cleaned the carbs hard, replaced various bits of the carbs with oem spec parts, compression is low but tolerable. I suspect there's a vacuum leak on the carbs but I was gonna wait till winter to split them and replace the butterfly valve seals. My personal opinion is there's a lean condition due to a vacuum leak somewhere, and the agm battery doesn't have enough electric fairies to get her to go. But I'm a newbie and was hoping someone could tell me if my line of reasoning is reasonable. Thanks in advance.

 

I can't remember exactly what it was putting out just that it looked adequate and I didn't make a note of it.

Thanks, I'll look into returning it. I've been looking at the forums for recommendations and will hopefully have a new battery soon.

 

P.S does anyone know a part number for the fuel crossover tube o rings? That's leaking now, and I guess that means I'm splitting the carbs. I've already got the throttle shaft seals I was saving for a rainy day.