I, too, replaced the battery on my V7 Classic with a MotoBatt MBTX14AU. Fortunately I haven’t had to replace the battery yet on my V7 ii Special. However, I have checked out what might be needed.
The MBTX14AU can’t be used as it is the wrong size for the V7 ii Special.
The MBTX12U will fit. It is slightly smaller, height wise, than the standard YTX14-BS , but produces the same CCA (Cold Cranking Amps) of 200. MotoBatt state that this is the replacement for the YTX14-BS. It looks as if the MBYZ16H will fit. It is a bit heavier than the MBTX12U, but produces more CCA at 240.
But all that is old technology. When the time comes, I shall replace it with a LiFePO4 battery - NOT Li-Ion, as I do not want to take the remotest risk that the battery catches fire beneath my seat, and underneath the petrol tank !
The MotoBatt LiFePO4 replacement for the MBTX12U seems to be the MPLX16U-P. It weighs just under 1k, a saving of 3.4k, produces a CCA of 370 and is slightly smaller, height wise. The downside is going to be cost at just over £100 on eBay. Or it could be the MPLX12U-HP which only seems to show on the US site, but is available on eBay. A bit confusing. Currently it is my choice - slightly lighter again and producing a CCA of 280
The other downside of a LifePO4 battery appears that, whilst it can be used below freezing point, it should not be charged below freezing point as it can be damaged. This could be a problem because as soon as the bike is started it will start to charge. This will not be a problem as far as I am concerned, as I do not go out when the temperature is anywhere near approaching zero; but it could be a problem for the hardened biker who has to commute year round. A check on the charging characteristics should be investigated. It also needs a special LiFePO4 wall charger.
Have a look at: http://www.motobatt.us/information-lifepo4-lithium
There are other LiFePO4 batteries. Cabernet refers to the use of an Aliant. I have referred to the MotoBatt as I like the yellow casing. How shallow!!
Please do your own research. Mine is not definitive, and is theory not practice.