Rincon no forward, just reverse

My 2003 Rincon will not go into gear just reverse. When I try to force the shift lever forward it will grind gears but will not slip in to gear. I have tried adjusting my idle down but that does not help. It works in reverse just fine. Help!

My oil level Is good. The shifter lever is not going all the way forward, I can force it forward but it still does not go in to gear and I have to pull it very hard to get it back in neutral or reverse. I did some research and I think it might be the shifter drum.  

Sounds like the forward gear popped out due too the shift cable not being adjusted correctly.I've seen this fairly frequent. If this is caught the first time it happens it's a simple cable adjustment. You will want to try this first before tearing into the back of the motor. The cable is adjusted by taking the fuel tank off and the bottom plastic shelf out, you will see the adjuster lock nuts. With the bike in nuetral and shift lever in nuetral loosen the jamb nuts and make sure the the adjustment is not bias in either direction this will make sure u have the same amount of travel in either direction.It's a farely big job too inspect and replace the damaged gears you may want a qualified tech to preform the repair.