Jumps time

[Keith McClelland]

I have timed my 2020 450 sector for two days in a row.  I set timing and sector cranks.  Drive normal and after I come to a stop it dies and  not start.  Set the timing again and one ride around the yard and it jumps time again and won't stsrt.

[aefron88]

Is the tensioner wound up and installed properly? does there seem to be good tension on the chain when installed? How are you determining initial timing? and how are you determining it has jumped?