I just did a Valve adjustment on my 98 Gsr and I know i did them to the specs that were in my haynes manual and Cspeedracings website.. It purrs really nicely now but my Idle is weird. when its in neutral it is at about 400-600 rpms (it kinda bounces around) , and when i start to drive in 1st it drops to 200rpm right as i first step on the gas then goes up normally.... WTF?

 

You may be a little on the tight side. With the three hondas that I have owned, they only purred when they were a little tighter than spec. TOO used to be a fan of this. My idle was normally a little strange also. I have always gotten a little noise when tightened to spec.

 

disconnect the idle control sensor and screw the idle up a little and see how it goes from there, i had mine adjusted about a month ago 9the first time since new -72K) and they sound exactly like they did before i got it done, but my idle was too low when i got it back (600rpm) so i adjusted it up to 800rpm.