'87 N/A Ignition Timing
 

Can anyone tell me the correct ignition timing for my "87 N/A. I have timed it "by ear" and have it running OK, but when I put my timing light on it, it reads like 60 to 70 degrees advance. If I move it much off that setting, it barely runs. I am using a Craftsman light with the dial advance on it. Is that my problem with 3 fires per rev instead of 1 every two like a 4 stroke??? I would like to get my timing to spec., because it seems to have a big effect on high RPM power but that is hard to tune by the seat of my pants!!!!

Thanks for the help!