Hi guys, I am new to this channel & i own a 2012 Yamaha R125. #My bike was working fine untill the weekend where i didnt use it for 4 days. I tried starting the bike, but the battery was flat dead. I used a RAC 400 jump starter kit. It is able to give out enough charge to start the bike, but the engine gives a Big POP noise. In london weather was pretty cold and i suspect this could be an issue but i may be wrong. I am concerned that it may be a major issue. Can anyone suggest some solutions ? * the bike has been regularly serviced, oil is fine (10w40 MOTUL), coolant is fine.