Hi, I just got a good deal on 6 new toys. One is a 70cc Zei ( Chinese quad ). Believe it is a division of Zstar which makes atv's. I tried a borrowed battery the size of which fits the quad as well as a slightly bigger one. The batteries were fairly well charged up & cleaned connections. Relay only buzzes'. Tried a car battery with starter on & off the bench & it works good & got engine to start. Should I buy a new small sized battery or ? I have room in the chassis to make & install a larger battery box. It is an auto with no pull or kicker. Engine turns quite freely by hand at clutch but starter does seem kinda tight to turn. What do you suggest ?