I bought the MB18U for the 92 I am working on. At the time I bought it Murph did not have any listed so I went to ebay and got it from Motobatt. When the battery arrived there was not enough charge to spin the motor, only 10.3Vdc. I put it on a tender and emailed the seller on ebay about it. After two weeks I had no reply from the seller and the battery does not seem to be holding charge for more than a few days. I sent a second email to which there was no response again. After another week I placed negative feedback. Fast forward to this week. The seller contacts me and says they will send a replacement battery once I send back the battery lid and caps, I have no problem with this as the one I have is crap at this point. I did tell them that I would only change my feedback after I have a new battery and can test it.
Today I get this response to my email
Okay, Stan, this is what we have. I have had the sales guy test 7 different batteries for me and they all have sulfated evidently. We are shipping several whole pallets back to the manufacturer for a different load. All the batteries were no good.
As a result they refunded full price with shipping (we all seen others that won't refund shipping) and I am the proud owner of a marginal battery, but not out any money on it.
So if you are thinking of getting a MB18U from Motobatt on ebay hold off for a bit if you can. No need to risk having a dud shipped to you.
As far as Motobatt batteries go, I have no problems with one I bought for the GS500 a while ago and I know that Murph sells them, so they have to be decent because Gary looks out for us.