Could be a running to lean condition that is causing it to cut out at High RPM's or maybe in the drive trane, or could be that the float setting in the carb. is not right and the engine is starving for fuel at those high RPS's.
How many miles do you have on your engine?
Did it just start doing this or has it done it since you had it going?
There is more than one thing that could be causing this problem, so I say check everything very good and start with removing the spark plug and see what the color of it is, if it is very light to hite in color, move the clip down one nothch on the mtering needle in the carb. clean the spark plug very good and test it again to see how it runs, even if it runs good and the "jerking" stops you should still check the plug and make sure it is a medium to light brown, if it is still very light white or gray then move the clip down another notch and repeat the rest until the plugis that medium to light brown. there are soem other variables to this proccess, if you are running Opti II oil it will probably be a little lighter than it will be with conventional oils.
Maybe this will be a start for ya and I'm sure others will chime in here and possibly give you some even better advise.....
Best wishes....Peace