the best way is with a laser. take the plastic off, mount the slider, aim the laser dead center on the slider (making sure it's level etc), then dismount the slider and remount the plastic. that's the most precise method by far
using the forward motor mounts puts the sliders way too low on the bike and in a lot of cases will tip the bike up on its tank. i never bothered with sliders on the 51 for that reason, they don't help.
thorsten mounted a set higher up on the frame so they won't pitch the bike and damage the tank
i managed to lend a dewalt laser level and 51mm hole saw + arbour from work .
i then set about potentially destroying a nice set of honda OEM panels i honestly could not bring my self to do this to the side panels i had so i purchased a second handset and the once that were fitted are now stashed away ..
the photos can do the talking from here .. i am happy with the results tho ..
next job is painting ... then to fit new acoustic foam and heat protection..
then theres stickers to address ....
BHP is how fast you hit the wall... torque is how far you take the wall with you