12v 5ah weak spark kick only headlight taillight

[Jangus]

I have a 1980 Xs that is kick only with a headlight and a taillight. I'm running 1.5" headers into cocktail shaker after market emgo exhaust with mikes Xs pod filters. I've went with a 12v 5ah battery and I'm getting a weak spark that is fouling the plugs. I've moved from a 7 to an 8 sparkplug but The plugs are crapping out after ten minutes. I want to run a smaller battery and have read that a lot of people are running even smaller batteries with the same set up. When hooked up to a stock battery everything is fine. How can I still run the smaller battery without changing my charging system? What should I be looking for in my wiring that could have gone wrong to not be able to run the smaller battery? Any help would be huge I'm getting confused seeing that people are running the same set up and it's working for them.

 

[Underdog]

for starters a 8 is colder than a 7

 

[Underdog]

and do the the plugs look terrible or just act terrible? some pics maybe?

 

[Jangus]

I'll post some picks after work thanks

 

[emzdogz]

maybe it's the coil or plugs wires? was it ok before you started using that battery?