The CAM, GEARSHIFT will only turn 2 times. There are Five gears, And the gears on go into 1st and 2nd. The gears are very hard to shift into.
There are a few root causes for you consider
Bent shift fork(s) - Your shift forks slide various gears along your primary and secondary shafts of your transmission. Every time you depress or raise your shift lever with your foot you are turning a drum called a 'shift drum' This drum has grooves on cut into it that move the shift forks along a shaft and move the gears to engage or disengage them. If you had a particularly poor shift a gears dogs or slots can bounce off one another forcing the shift fork to bend as a result. A bent shift fork requires the engine cases to be split in order to to remove them and resolve the issue.
Broken shift drum - A broken shift drum, in any way, is a very rare occurrence. The shift drum spins and has grooves cut into it to slide shift forks back and forth to slide gears along transmission shafts.
- Issue with Shift Linkage - You could very likely have an issue with your shift linkage. Many times, the return spring for the shift lever will wear out and eventually break. You can validate by putting your rear wheel in the air in order to spin it and try and operate the shifter by hand while spinning the wheel. If the shift lever is not returning to it's original place properly you can dig into it further to discover the cause.