I did some twisty mountain road riding and noticed something with the stock carb. The transition from high rpm deceleration to acceleration was kind of abrupt. I played with it and concluded the carb slide needs to break the suction of the high manifold vacuum as it opens, then it moves more easily. This made it hard to ride smoothly at the edges of tire adhesion. I either had huge engine braking, or a big power surge, but couldn't open the throttle smoothly enough. You would never notice this in the dirt. This tendancy is always there but it became conspicuous when I reached 12000+ ft altitudes where it was gone. At high altitudes, the intake manifold vacuum is way less due to thinner air and reduced volumetric efficiency. At 12k, the throttle opened smoothly with no feelling of being stuck, then releasing suddenly. What a huge difference in control of power. I spent 4 days and 850 miles riding so I had plenty of time to confirm this. Does the edelbrock flat slide carb do this as well? I have a CRF and the flat slide rides on rollers, but the edelbrock doesn't. Seems like it could be sort of sticky under high vacuum conditions. How about you supermoto guys, Is there a difference in throttle transition smootheness between the two carbs?