The 850s I work with all have the same problem.......when shutting off the throttle, the motor is slow to reach an idle. This occurs from 3000 downward and actually seems like the slide is slow to return. With a 750 this doesn't happen. At around 2500 there is a "shudder" and it's become annoying passing through this point every time. Most 850s I work with have a single Mikuni, and I don't remember if the problem exists with dual amals. So what kind of carburetion do you have and do you experience this? I've tried different pilot jets and different slides with no real change. Currently I use the same jetting as the 750 which works well. The slide is a #3. I consider it slightly lean but a 2.5 will foul plugs quicker but gives better low end response...a compromise.
Is it possible that the balance factor for an 850 using isolastics produces this small problem? My next idea is perhaps the motor would benefit from a pair of JS lightweight pistons and the shudder will possibly disappear.
To sum up...is it a carb problem or a reciprocating mass problem?
