yz125

i work at a machine shop and plan was to extend the swing arm 6" and then moving the mounting position back so that would compensate for the length its not much longer i was more worried about the resi and if it would support the blaster
 
springs are supposed to support the weight of the quad, not the hydraulics within the shock. shocks are just there to control the oscillation of the springs


you should only use the nitrogen pressure that is recommended.
 
the rear shock on my '91 YZ125 is 18.5" from eye to eye, you could contact a shock service place to see if you can get it re sprung to get it the way you want it.