03 kx125 tranny problems

[frequentflyer]

purchased an 03 kx125 for my son last week. the bike ran great when we tested it out. took it to the track this weekend and it started making a knocking noise in tranny. sound is coming from area possibly just inside countersprocket area. when the bike is in neutral and you turn the back tire you can hear the knock with every revolution of the countersprocket. it will not make the noise when you turn the tire in the reverse direction. its like the bike is trying to shift in to first gear. if you crank the bike in neutral while on the bike stand the knocking is a louder and the bike will jump into first gear. while my son was riding the bike you could here the noise clearly in first and second gear. sounded like a chain rattling real bad but it wasn't. third thru sixth gear was fine, no noise at all so just kept out of first and second while riding.
also it sort of comes and goes. occasionally it would not make the sound. now here is whats funny. if you turn the rear tire while the bike is on the stand and in neutral and then pull in the clutch the rear tire will stop like it is in gear. now to make things worse i don't have a manual. i did check the clutch all the way down to the clutch basket and every thing looked great. however i had to adjust the clutch several times yesterday. ok just went out to garage to make sure i didn't miss anything and found the tire is turning while on the stand in neutral but when i take it off the stand the bike will not move as feels like it is in gear. i hope this makes sense to someone. if anyone has any ideas at all please let me know. OH ! the previous owner ran 80 wt gear saver and i changed to 10w40.( maybe the thick oil he was using was covering up something) THANKS

 

[MXP1MP]

Hopefully it's not the same issue I had with my '04 on my '04 only after 17 hrs from new the input shaft bearing exploded! This is the bearing that is pressed into the case it wasn't making any noise but I had no idea what was going on, I finally found out what had happed cause it was resting the the clutch push rod and the road finally snapped. Well I had to split the cases and to find there was all kind of metal shaving from the bearing or more like what was left of the bearing. There was like maybe 1/4 of the bearing race left and maybe 4 of the ball bearings left. It spun in the case cause me to replace them! Along with all the bearings in the cases and I mean all of them! I also had to replace 2nd 3rd/4th gears and had to replace the main shift fork. Once I fixed everything it's been rock solid since and I have like 4 times as many hours on the bike since then. This must of been such an issue cause kawi updated the center cases for '05 on the under side of the bearing race on the case it's self the drilled out a small oil hole/groove. I didn't do this mod to my bike I just started adding alittle more oil to the bottom end. It takes stock 700 ml's and I started putting in 740ml's of oil and using nothing but 80 weight maxima mtl. Stop ridding the bike and look into asap I had to split the cases to find out what happened and it was shocking to say the least. Btw my bike made no noises and gave no signs of this was happening either.

 

[nickyd]

grab the output shaft and try to wiggle it up and down - see if that bearing is going.

 

[kawaguy]

drain your tranny oil and look for any metal shavings, sounds like something is loose, possible gear tooth or bearing