KX65 jumping out of gear

[SquareAce]

2004 KX 65 sometimes goes into neutral while in gear. I gave this bike to my son today for Christmas and when he would try to go from 2nd to 3rd the bike would suddenly hit neutral. This happened frequently with him riding.

I rode the bike (which I am way to big for) and didn't experience the problem as frequent but it did happen a couple times, once in 3rd and once in 4th. Both times I pressed the lever down and it went back into the gear I was last in. It did seem to happen when my boot first hit the shifter.

Some quick searches leads me to think it is gear dogs or shift fork.

Does anyone have any other ideas before I split the case to check out all the transmission parts?

[MJP68]

2004 KX 65 sometimes goes into neutral while in gear. I gave this bike to my son today for Christmas and when he would try to go from 2nd to 3rd the bike would suddenly hit neutral. This happened frequently with him riding.

I rode the bike (which I am way to big for) and didn't experience the problem as frequent but it did happen a couple times, once in 3rd and once in 4th. Both times I pressed the lever down and it went back into the gear I was last in. It did seem to happen when my boot first hit the shifter.

Some quick searches leads me to think it is gear dogs or shift fork.

Does anyone have any other ideas before I split the case to check out all the transmission parts?

Sounds like you are on the right track, the bike is 12 model years old. Worn or slightly bent shift forks would be my guess, but either way you have to split the cases.

just make sure the shifter is getting a good bite on the shift shaft (no slop between the two)

Edited December 26, 2015 by MJP68

[SquareAce]

Will do thanks

[crazyal426]

I have also seen the the teeth on the shift shaft bend and crack where they engage on the shift drum.  That may cause it to not fully click in when the kid shifts but will when you do it 'cause u have a bigger foot.  One more thing to check.

[SquareAce]

@ crazyal456

Can I just pull clutch and pull the shaft all the way through to change that?

[crazyal426]

SquareAce, Yes!   Don't forget to drain your fluids. Once you pull the clutch cover off, the clutch basket off, shifter, then the shift shaft will slide right out.  Keep in mind that the problem may me deeper but this is not a bad place to start.  I would not buy any parts until you pull it down.  Make sure you order a new clutch inner hub lock tab when you order parts.

[SquareAce]

I didn't see your post before ordering and didn't get the lock tab for the clutch basket. Hopefully the tab won't break while removing or reinstalling.

I'll let y'all know how I get on when the parts come in from partzilla later this week.

[SquareAce]

I found a little roller thing on the shift mechanism that was broken off. I ordered part and decided to go ahead and change the shift shaft since I had already bought that part. Could the broken rolller thing be causing my problem with the bike going into neutral?

I could not get the clutch basket off. The center bolt seems to be stuck. I used an impact wrench and the bolt just wouldn't budge. I would be able to get to the broken roller without removing the clutch basket but I want to get that basket off. I was trying to turn the bolt as if it had standard threads (right handed bolt). Is this bolt left handed?

[SquareAce]

This is the broken part. 13236A/B

[SquareAce]

I replaced the shifter shaft and the two rollers that hold the bike in gear. This did not fix the problem of the bike going into neutral.

I didn't run the bike but was able to see with the engine cover off that the bike was not engaging in gear sometimes. The bike will shift if you give the shifter a good yank. The roller that was broken springs down into a round dowel holder. There is a gear between each of the dowels on the holder. Sometimes the roller stops on top of the dowel which is between gears.

I'm wondering if the round dowel holder is rotated on the shaft it is attached to. The shifter just doesn't rotate the round holder far enough.

[MJP68]

I replaced the shifter shaft and the two rollers that hold the bike in gear. This did not fix the problem of the bike going into neutral.

I didn't run the bike but was able to see with the engine cover off that the bike was not engaging in gear sometimes. The bike will shift if you give the shifter a good yank. The roller that was broken springs down into a round dowel holder. There is a gear between each of the dowels on the holder. Sometimes the roller stops on top of the dowel which is between gears.

I'm wondering if the round dowel holder is rotated on the shaft it is attached to. The shifter just doesn't rotate the round holder far enough.

Are you spinning the rear wheel while checking the function? Most sequential gearboxes require one or both shafts to spin to be able to shift properly.

[SquareAce]

Yes I had rolled the rear wheel while I had it on the stand when I shifted gears. I tried by rolling the wheel forward and tried rolling it back and forth and tried while not rolling. The roller supposed to seat between the dowels but sometimes it rests on top which is out of gear.

[YZPaGuy]

I never rely on trying to shift a motor on a bench. They are meant to shift while running and under load. This is especially true with a cover off that puts pressure on a shaft when bolted tight. I have split cases partially reassembled to check the shifting, it will always seem like it isn't working correctly. I just check to make sure nothing is binding. Unfortunately you have to put it back together and try it. That's the only way to know if it's right or not. 

[SquareAce]

Thanks. I went ahead and reassembled the bike tonight. I rode it and it shifted great with me but the real test will be tomorrow when my son can ride after school.

[SquareAce]

Update

All is well with the KX as far as the gear jumping goes. My son rode a harescramble this past weekend and no problems with the gears.