2000 suzuki rm125 shifter problems?

When i shift gears the shift lever does not go back into position. what could be causing this? i look at a parts diagram and it shows a spring on the gear shift shaft. could this be the issue?

Possibly.It's also possible that the shift shaft is bent - ever crash the bike?Drain the oil, remove the clutch cover and inspect the shift linkage - unless you have a crystal ball :)

The spring that brings the shift shaft back to nuetral may have broken or the cam pin in between the spring may have come loose dissallowing proper shift function.Guardrail is also correct about a bent shift shaft.I rode dirt and street for 25 yrs.