My 2005 r6 had all maintenance done chain and sprocket . new clutch and brakes but when i'm riding 3rd gear seams like the chain is slipping off then catching and when it catches it jumps to a high rpm . whats the problem?

slack adjuster too tight, bar jammed into sprocket,clutch slipping, chain brake on in off position,chain binding on sprocket or bar, broke end on crank, sprocket slipping on end of crank, a clogged/pinched bar guide,etc.

If the oil pump gear is driven by the back of the sprocket you must make sure the the sprocket has engaged into it correctly if it has not the sprocket will bind on the back of the clutch

Sounds like the chain is too tight (should usually be 30-40mm of slack) or the out of alighnment.

By chain sound do you mean a metalic rattle when you ride off?
I will assume that is not making that sound at idle. It could be that your cam chain has stretched and needs to either be replaced or tensioned.

If it is a pinking sound, sort of like someone tapping on a tin can with a coin. Then that is most likely preignition which isn't good for your engine. Why octane/RON fuel do you use?

I assume you're talking about the primary chain. To get the primary chain off, you must remove the compensator sprocket from the engine shaft and disassemble the clutch, which takes a special tool to compress the clutch spings, and remove the outer clutch basket. The outer clutch basket is held on by a large nut on the inside that has left-handed threads on it. Once you have all that off, you can remove the four "trapdoor" bolts and pry the transmission out.

Good Luck
Steve

It could actually be that the countershaft sprocket has stripped-out the splines that engage it to the countershaft. Take off the cover and have a look at the sprocket. Hopefully it is only the sprocket that is damaged and not the transmission shaft that it mounts to.
Another possibility is that the clutch cable has somehow gotten waaay out of adjustment. Just feel the clutch lever; you should have some free play at the lever. In other words, the first 1/4" or so of lever movement should do nothing except take up a small amount of slack in the cable.
Are you sure it is actually going into gear? Or have the splines on the shift shaft stripped-out? These are the things I would check first. If it isn't one of these, then I predict some major transmission work is in your future.

This behavior is the symptom that your clutch plates are getting worn out. Since power is transmitted from the cam shaft to the front sprocket (smaller dia) is better at lower gears but once the rpm increases the clutch plates do not catch up with the cams rotation, hence slipping at higher gears & in between 4th & 5th gears the pulling power of the engine seems to go to neutral before engaging again. Check your clutch plates as well as the sprocket-chain- rear sprocket for wearing out of the gear teeth & replace if required. You will get back full power & acceleration as when the bike was new.............sodeep

You need a new transmission the gears are stripped off. I had the same problem

No.That was the problem.The chain and the sprockets needed to be renewed.
When you will take, the rear sprocket's base, off the axle check it's bearing.Just put your finger in and turn it slowly to see if it "locks" instantly.It will be nice if you renew it now that you disassembling the chain drive system.