my express 400 is hard to shift into low gear and then sometimes it goes in to low gear just fine high and reverse work justnfine what is the probplem

 

Make sure engine idle is not too high. Check that linkage arms on the transmission are tight. If these are ok,then either the shift linkage needs adjustment or the shift box parts are too worn to get a positive low range. Have the shift lever in neutral,remove the linkage ends from the shift box levers,loosen the lock nuts on the linkage ball ends and turn in or out to adjust to where they drop straight into the shift box levers with no resistance or pulling. If this doesn't help on shifting,could be time to rebuild the shift box,if all parts are still available. Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse