Need Help with Transmission/Gear problem for my 1991 KX 250

I am need of some help on an issue that just started with my KX 250. While riding yesterday my bike suddenly started to jump out of gear. It will not engage first gear unless I keep my foot down on the gear shifter and with other gears it does the same while riding it just disengauges on its own back to a neutral gear. The bike was running fine and strong prior to this issue....The only mistake that I noticed that MAY have contributed to this problem is that I recently changed the motor oir and noticed that I exceeded the level (To much engine oil) I dont know if this could have contributed to my problem but I cant think of anything else...Can anybody please offer me your opinion/advice on what may be wrong with my bike....

Thanks guys
Tony    

its jumping out of every gear??
reset the fluid level first but i dont think thats the cause.
do you have a manual? I would suggest checking the detent spring on the back of the shift drum. you have to remove the clutch basket to see it and you have to remove the right side case to service it if it did fail.  

Autismspeaks.org
Gilbert AZ
06yz144,05yz85,02yz85

Thanks for ur response MJP68


Yes it is jumping out of every gear...I was planning on resetting the fluid levels..But it definately feels like a spring failure of some sort. Unfortunately I dont have a manual for my bike at this time...  

part id # 92144 is my suspect.

91 kx250 shift assy  

Autismspeaks.org
Gilbert AZ
06yz144,05yz85,02yz85