if you are unable to get into 1st from neutral, try releasing the clutch lever while in neutral then pull the clutch lever back in and then try shifting into 1st. this has worked for me on several different quads.
Hey i had that problem right after i moved my shift lever down a tad bit it was barely hitting the frame so it wasnt going into first. This may be your problem if u lowered your shift lever. I thought i would share it. Hope this helps