Hi to all. Like my friend atreiu, I have a '91 XR 600r with 644cc, worked head, hotcams and open exhaust. The pumper is a 41mm FCR, the jetting is the same suggested in the thread, except the main jet (#185). I have the following issue: on acceleration and at full throttle all works perfectly, but when i decelerate (also slightly), the engine becomes very irregular, and it pops. Then I have to close and reopen throttle completely, if I want that the problem ends. What happens?