Bike Battery Amp/H

Gidday,
Went to go for a ride yesterday and had a flat battery however it started ok with a jump.It has been a couple of weeks since the bike was started and I am not sure how old the battery is. I just thought the cold weather may also have something to do with it.It has been ok for the past 5 months when I got the bike. Anyway today I decided to get a new one and have it here just in case, but when I checked the battery in the bike it is rated at 14 Amp/h and the owners manual states the battery should be 18 Amp/h. I start ringing around for prices and then realise why the last guy has put this battery in, $$$$$.
Does anyone know if apart from going flat quicker, would there be any damage done to the electrics/computer on the bike if I replace it with one of a lower output than recommended?
If not should I simply replace the battery with another 14 Amp/h, and expect to replace it earlier. I could get at least 2 batteries for the price of the bigger one.
Thanks for any advice.
Went to go for a ride yesterday and had a flat battery however it started ok with a jump.It has been a couple of weeks since the bike was started and I am not sure how old the battery is. I just thought the cold weather may also have something to do with it.It has been ok for the past 5 months when I got the bike. Anyway today I decided to get a new one and have it here just in case, but when I checked the battery in the bike it is rated at 14 Amp/h and the owners manual states the battery should be 18 Amp/h. I start ringing around for prices and then realise why the last guy has put this battery in, $$$$$.
Does anyone know if apart from going flat quicker, would there be any damage done to the electrics/computer on the bike if I replace it with one of a lower output than recommended?
If not should I simply replace the battery with another 14 Amp/h, and expect to replace it earlier. I could get at least 2 batteries for the price of the bigger one.
Thanks for any advice.