Thanks all!
The unf threads were pretty poor so the insert doesnt go all the way down the shaft, i added a few mils of recess after the photo was took so the bolt would sit further in like original, but didnt want to go too far as i would loose too much thread.
This unfortunately means the bolt doesnt actually reach the push rod, but that's ok as I managed to get one of the TTR400 manual adjuster bolts, so this will remain backed off and locked. Suppose I could make a longer version of hondas bolt if it came to it!
