I have owned my fzs1000 since march 2006[it was one of the last of the gen 1] at 2000miles I fitted a hyperpro front & rear springs which I was quite happy with until last year when at 21000 miles it was time to spend a bit of money on the best bike I ever owned,so last june I fitted a the upgraded r6 shock together with a set of Avon storms xm & a genuine chain & sprocket kit,the one thing I was disappointed with was the vibration thru the handlebars as I remember fitting chains kits to XS650s/CB750s/Z1 etc & it was like having a new bike but after fitting the original sprocket kit I was a bit disappointed that the bike felt no smoother than before,when I was over the classic tt last August I asked a friend to take my bike out to see what he thought & he confirmed there was to much vibration there so when I got home I reved it up to 4000rpm on the mainstand to confirm how much vibration was there,i then slackened all the engine bolts off & restarted it on the main stand & reved it to 4000rpm & all the vibration had gone,i was so happy it had just gone & this bike has not been fitted with the ivans kit yet,i did then torque all the bolts back up to the correct figures but the vibration had come back,i then undone the bolts again & just done then up by hand & it has been super smooth since then,i just come back from the tt where I clocked up 1000miles & it still super smooth & all the bolts are tight so hope this has helped someone
