Can I use water or do I need battery acid

[patastinky]

Or scooter battery. Thinner, slightly less CCA (that we can't use), standard MC connections. I put one in my RD400c project, Mighty Max YTX5L-BS with 55 CCA for $22.99 from Amazon. Sealed AGM that is the same length and height as the original but thinner. Designed for scooter, but should handle the RD fine.

This one?
Mighty Max Battery YTX5L-BS Motorcycle Battery Replacement - 12V 4AH - 55 CCA Brand Product https://www.amazon.com/dp/B00K5396HU/ref=cm_sw_r_cp_api_glc_fabc_jSPZFbHT6XSW4

If so for $25 I'll pick it up and try it

[pidjones]

Yes, that looks like the one. Mighty Max seems to be a stand-up company, too. I first ordered one that their Amazon ad said fit an RD400, but it was an inch too long. They refunded 100% and said to keep the one that wouldn't fit.

[RDFL]

Had one of these in RD for years no problems.  https://www.ebay.com/itm/Kawasaki-50CC-KFX50-2007-2010-ATV-Battery-Replacement-By-SigmasTek/223131977883?

[patastinky]

thanks, guys. All really good stuff here.