hi guys,,, after about 30years of my xs650 1976 34mm never ever being maintained,,, after i did my suzuki by flushing with new kero until it ran clean on each side i put progressive springs from usa, in with BEL-RAY 10WT fork oil what a difference,, i then did my xs650 it was just gunk that came out of the forks,, again i flushed them cleanwith kero as it does not hurt the seals,,,, i then put 180ml of bel-ray 10wt fork oil in each tube and bing a difference,,,and a far better ride at some point i would like to strip the tubes and cross drill the lower holes in the bottom of the 34mm which will make them damper alot better hope this helps you