Dr 400 std bore size = 88mm .... pin size = 20mm
It's up to you as far as compression ratio are concerned , 10:1 11: 1 12:1
Yamaha XT TT SR 500 run out to 89mm being 2mm there 2mm O/s with a 20mm pin
I've gone in a different direction with a Honda set up using the 21mm pin 89mm > 95mm