i have a 1982 yamaha xs650, heavily modded, kickstart only. it came with a tiny battery the size of a deck of cards. you turn the bike on to start it, and this battery has just enough juice power it up to start. in theory. in reality i think it's not quite enough. i've always had difficulty kicking it over, but if i jump it, it starts right up.
i don't have space with the current configuration for a typical battery, which is why the previous owner used this one, which fits in a hollow under the seat. the battery is rated at 12 volts/0.8 amp hours.
1 - i'm wondering if anyone knows of similar small battery that would work in this application.
2 - can anyone recommend a minimum amp hour rating? would a higher rating solve my starting problem.
any help would be hugely appreciated.