CR125R shifting problems

[VintageGuy]

Okay, so here's the update on the shifting problem.

I took off the right side case and removed all the shifting linkage pieces and cleaned and inspected them all. Didn't see anything worn or broken. Good.

Next I did find that the shifting drum would not work through the gears, even by hand. After some wrangling I got it to shift through all gears while moving it by hand. Good sign, I thought.

I re-assembled the bike to test it out. Rode it down the street shifting through all gears. I thought, great my son can ride tomorrow with me. A short time later he calls me over to tell me that it won't shift, again.

The problem still exists so I guess it's time to pull the guts out of it now. Great, I guess I didn't have enough things to do so let's pull apart a Honda motor next week.

I get it now, it's a father/son bonding opportunity!

Thanks for all the very detailed help from all of you, it really helped. Now it gets interesting!

Bob

[JN Innovations]

I would just pull the motor out and rip it apart. The more you ride it with a damaged tranny, the more damage your doing to it. Did you see any metal when you drained the oil? If you got any, metal, I repeat, ANY, split the cases and find the damaged parts.

[VintageGuy]

Jon,

No, we didn't see any metal in the oil when we drained it. Plus, when I had the right side apart I didn't see any site of shavings or any chips on the gearbox teeth either. There is a large hole near the top of the center case that you can see into the gearbox from and as I spun the gears I was looking for any sign of gear breakage but didn't see any.

Either way, the motor is coming out and it's time to crack it open to see what makes it tick. Or in this case, not tick!

B

[JN Innovations]

Good luck, hit me up if you have any questions. I'll help you as much as I can.

[mxdad100]

Bob...roll up your sleeves and Get Er Done...but have your Son help you. It will be good experience, and bonding, all in one.

P.S. And Jon KNOWS everything there is to know, so take it to him if you can't fix it.

Happy Holidays to you and your Family,

Rob Dresser

[fbr]

Bob, This still sounds exactly like one of the springs and plungers getting intermittently stuck in the bore in the drum shifter. This problem will not leave any debris in the oil (consistent with the fact that you haven't found any debris in the couple of oil changes you've done while troubleshooting) unlike other damage to the gears or shifter forks. Also, your description, "Next I did find that the shifting drum would not work through the gears, even by hand. After some wrangling I got it to shift through all gears while moving it by hand." sounds normal. To shift the transmission by hand with the bike on a stand, you have to have one hand on the rear wheel and give it just a little bit of movement to get the transmission to shift. If you were doing that, maybe the plunger was stuck and freed itself. Before you pull the engine, I suggest you try to duplicate this problem I am describing. Pull the clutch off and shift abruptly, even banging the shift lever against the stops. Try to get the plunger to jam in it's bore. If it does, the pawl will not have any spring pressure against the inner ratcheting surface of the drum shifter, and it is not going to be able to engage the drum shifter when you try to shift in that direction (up or down). If you can duplicate this, I think you should replace the drum shifter, springs, plungers and pawls.

Originally Posted by VintageGuy

Okay, so here's the update on the shifting problem.

I took off the right side case and removed all the shifting linkage pieces and cleaned and inspected them all. Didn't see anything worn or broken. Good.

Next I did find that the shifting drum would not work through the gears, even by hand. After some wrangling I got it to shift through all gears while moving it by hand. Good sign, I thought.

I re-assembled the bike to test it out. Rode it down the street shifting through all gears. I thought, great my son can ride tomorrow with me. A short time later he calls me over to tell me that it won't shift, again.

The problem still exists so I guess it's time to pull the guts out of it now. Great, I guess I didn't have enough things to do so let's pull apart a Honda motor next week.

I get it now, it's a father/son bonding opportunity!

Thanks for all the very detailed help from all of you, it really helped. Now it gets interesting!

Bob

[VintageGuy]

Gents,

Thanks for the offers and ideas of how to fix this baby. I did give the spring loaded pawls a pretty close inspection when I pulled them out but didn't see anything that I would describe as excessive wear. But then again, I've never taken one of these apart before either.

I'll give them another look when I take it apart, again, later this week. If nothing else, Saturday is the full blown take apart day.

More to come...

Bob

[VintageGuy]

Hey Jon,

Maybe you could PM me your phone number, just in case?

Thanks,

Bob

[JN Innovations]

The shop number is 925-308-7355.
We're open Monday 9-5
Tuesday-Friday 9-6
Closed on the weekends.
Call any time during business hours. Leave a message if we don't pick up and we will call you right back.

[kramer707]

you broke a shift fork and its lodged in the transmission.