Im listening everyone but im sick reading again and again the same solutions such as "ohhhhhh it's your chain" or "be more smooth with your hand" or "use a gear up". Probably YOU don't want to listen because i said that i have drive other bikes and others drove mine. Im not the only that im seeing this problem. Anyways, my chain has the 25mm slack (as the bike, the owners manual and the service manual suggests). As i told, i tried with 15mm (I KNOW IT'S DANGEROUS, it was only for 2 minutes) and with 40mm. That didn't make any difference. For once again, it's not the gap, it's the way it's absorved.
I expect the problem to be something like worn outer clutch, worn rear gush rubbers, worn gush rubbers of the motor (if there where) or something related with ABSORVING vibrations. Something worn and have some loose that must not be, causing this hit when i open the throttle and the upper side of the chain tights.
With this knowledge and beliefs, really, you thing you can help?
Ok, the least you could do is spell properly. It would make trying to help you so much easier.
A worn clutch wouldn't cause this to happen, though you already said you replaced parts of the clutch.
You stated the Kush drive is good, so we know the problem is not in the rear wheel.
You say your chain tension is fine, so we know it's not the chain.
You say you replaced the front sprocket, so surely you also replaced the rear sprocket and chain too to not have any abnormal wear, though a front sprocket wouldn't cause an issue like this.
You say you adjusted the throttle free play, though free play wont cause this problem, as there is no freeplay in the throttle when you're on the gas. Free play will come into play when you're off the throttle, giving some room for the throttle tube to be rotated more even though it's fully closed, so the problem is not there.
You say there are no FI or check engine lights showing, so we know the problem is not with an electrical aspect of the bike.
So, this is what we have left for problems.
1) Improperly adjusted chain. I have no way of knowing if you're adjusting your chain correctly or not.
2) The problem is you cannot hold a steady throttle or have issues smoothly rolling off the throttle.
I fail to see what you having owned and ridden 5 other bikes has to do with this problem, because this is not one of those 5 other bikes. The problem is either you or you have something adjusted incorrectly. Then again, I don't know what this gap is you're speaking of. You mention the term gap but use it in multiple places.
But again, you're saying the problem is in the off and on action of the throttle, which points at problems of throttle application. Perhaps both you and your friends who have ridden the bike are not used to the gearing that you have on the bike. Gearing will change how power is delivered to the rear wheel, by either making it less steep or more steep of a gear ratio. By gearing down, where you get up on the revs faster but it's an overall slower gear (top speed is less), you will experience chain and transmission lash even more than you would on another gear ratio, due to the ratio.
Also, if it's causing you a 2 second loss on the exit of each corner, again, that points to an issue with the drive train or you, as if a mechanical problem was that bad to cause a 2 second loss when getting on the gas, you'd be hearing noises and possibly be having parts of your engine flying out of the cases.
Are you absolutely sure you know how to ride this "race bike" on the track? Having ridden other bikes and being a courier doesn't train you to know how to ride on a race track. Are you having the clutch in as you're going to the apex of the turn? Why are you completely off the throttle and not holding a steady throttle as you're in the turn? Improper riding like that will cause the upper portion of the chain to go slack, and once you get on the gas, the bike needs to take out that slack before power is actually being driven to the rear wheel.
When you are on the gas, the engine is pulling the chain, which pulls the sprocket on the rear wheel. This force is transmitted on the upper portion of the chain, whereas the underside is merely just flowing along and is slack. When you're decelerating and you are not on the gas, the rear sprocket is pulling the chain which pulls the sprocket on the engine. This puts slack on the upper portion of the chain and has the driving force on the bottom.
I'm 100% confident that this is your problem, which is attributed to again, either an improperly adjusted chain or lack of smooth throttle control.