How to fix 4th gear in 1997 yz125 - YZ 125 Yamaha Motorcycles

 1997 probaly 1998 too their option selction would not let me post for a 1997 Jeep would not shift into 4th gear which is overdrive I believe, also check engine light will come on and then it will not shift. Sometimes it will not start and no back up lights. OK this fix is is easy well I think it is. get yourself an ACTRON engine analyzer it shows any codes and clears them it is around 100.00 buck or take it some where and have the code failure cleared after you fix it. On the transmissin is a switch housing that in it is the backup lights switch and this switch lets the computer lnow which speed you have selected 1st 2nd third or Drive. if the computer cannot see this switch the engine will not start  and if you are driveing the CHECK ENGINE lite comes on and you  will notice it will not shift out of 3rd into overdirve or 4th gear. first unhook the negative battery terminal then remove the switch from the transmissin and open up the housing and clean and lube the switch contacts reinstall the housing line up the rod going thru the transmission check it for operat watch the backup lights and have the code cleared out using you code reader or at a friendly parrts store or seervice staion best to have one of these readers any way they are worth their weight in gold. This repair saved me about 400 bucks doing it myself the switch is overpriced it is around 330 bucks. Well if have have these symptoms I would say this is the fix!!