If I were to change the battery in any bike I'd likely go with a LiFePo4. Small, light, and fairly cheap on
amazon. The standard battery in my CBR1100 was about 8#, the replacement Battery Tender branded LiFePo is about 2#. The battery I took out was still good, tested with two Midtronics inductive testers and a load tester, but the new one cranks so much better. It also holds the charge for a very long time between uses and it recharges faster. It was pretty close to the $ of a Yuasa which made it a no-brainer. Just for fun I used it to start my forklift and it cranked as good as the battery it normally uses that weighs about 40#.