can anyone who has this motor or similar 583 etc. give me a suggestion.?basics are all covered and sled runs great overall...i am just a perfectionist. there is a slight "breaking-up" effect in throttle response from just after clutch engagement at 4700rpm, up to about 5700 rpm. this is only with slow GRADUAL acceleration or deceleration. after 6000rpm the throttle response is silky smooth and very responsive. has anyone adjusted their slides richer or leaner a little? everything is stock now, at the standard factory adjustment settings. has anyone replaced their rotary valve to eliminate this poor response area in the throttle action. it is just about at the end of the first stage in the thumb throttle range, just before you would start to open the second thumb throttle range. accelerating slowly the motor sounds a little crackley. decelerating slowly the motor makes a burbling noise that does not sound really bad, it just isnt what you should hear when you let off the throttle with a 2stroke. sea level trail rider.thanks if you have any thoughts.