Setting the Timing on KZ 440 LTD

Hello,

I've recently rebuilt a KZ-440 LTD and upon starting it, just got pings and pops (ie. the bike would struggle to start) instead of firing up. I've set the cam timing (by aligning the arrow marks on the cam sprocket to be parallel with the cylinder head of the engine and with the ATU being set at top dead center). Is there anything else I need to do to set the timing (ie. use a timing light, etc.). I guess I figure my problem is timing so I'll start there and if the timing is correct then I'll move on to other potential problem areas. Thanks!!

Kirk