125m transmission woes - video inside

[rdlsz24]

Hey guys I bought this '84 125m last winter knowing it was "stuck between gears because the chain fell off" as the seller told me. I figured it was something easy and the price was right so I bit the bullet. I just now got around to tearing into it.

It seems very weird. Taking the right outer case off I can't see anything broken. The symptoms are it won't fully engage up or down from where it is in the shift pattern. It doesn't seem like it's in neutral since I can't turn the sprocket on the engine by hand. But it also doesn't seem like it's in gear because I can start the engine and watch the front sprocket and it doesn't turn.

Below is the video. Watch the upper left corner. The star-shaped thing (it's name escapes me at the moment) never gets fully engaged. In the video I slamming the shift lever both up and down. You can tell which way I'm going by which way the star is turning.



Does anybody know what the problem could be? I really don't want to tear into the tranny; I would rather find a good bottom end for it. I can do top end stuff all day but bottom ends scare me lol.

Thanks,
Rob

[rdlsz24]

Anyone?

Rob

[SWIGIN]

normaly the motor needs to be running to shift right....so that looks normal

[rdlsz24]

Even with it running it's the same thing.

Rob

[f4tty]

Hey Rob,

I don't have any answers unfortunately but I am having similar problems with my 125 so wanted to bump this thread back up.

If you come up with anything please let me know what the solution is.

Mine IS engaging still, however not often, most times I'm slamming the shifter and it's not engaging anywhere, and when it does engage it doesn't engage for long.

I also don't really want to rip my tranny apart..

Regards,

Caleb

[thefox]

rdlsz24 - Have you tried rocking the trike back and forth when you are shifting. The tranny gears have to line up as well so sometimes the needs to move a little. What about shifting the start piece by have, will it move?




f4tty - Are you saying that when you are riding the trike will pop out of gear right after shifting sometimes or will hit a false neutral between gears?

[f4tty]

thefox: Yep to both of those, it will drop out whilst riding and sometimes will hit that false neutral a LOT.

[rdlsz24]

rdlsz24 - Have you tried rocking the trike back and forth when you are shifting. The tranny gears have to line up as well so sometimes the needs to move a little. What about shifting the start piece by have, will it move?

Well right now the chain is not the rear sprocket on so rocking doesn't accomplish anything. I loosened up the adjuster on the rear end so I could put the chain back on, but without the front sprocket on the engine wanting to turn, I'm not able to get the chain back on the rear drive sprocket. There's just not enough slack to be able to do it. Is there an easy way to get at the front sprocket? It seems blocked by the sub tranny and some other stuff.

I'm not sure I get what you mean by shift the start piece?

Thanks for the replies so far
Rob

[elcamino12sec]

My atc 70 did the same thing as your describing. I replaced the shift drum stopper 5.99 and it work properly. The shift drum stopper is the piece that contacts that star looking thing. They will wear and bend after a while and not allow proper engagement and travel to allow for a correct shift. Try replacing that and see what happens. Its a cheap part and not very time consuming to replace.

[elcamino12sec]

It has that little wheel on it.

[thefox]

I'm not sure I get what you mean by shift the start piece?


Rob

opps, I ment the star piece.

[thefox]

thefox: Yep to both of those, it will drop out whilst riding and sometimes will hit that false neutral a LOT.

Sifter springs. There are 3 springs in the shift mechanism; I would replace all of them (they are only a few dollars a piece from the honda dealer). There are 2 on the shifter arm piece and 1 on the stopper arm. I have done this on other machines and it fixed the same problems, actually I need to do it on the 110 I just bought.

[rdlsz24]

My atc 70 did the same thing as your describing. I replaced the shift drum stopper 5.99 and it work properly. The shift drum stopper is the piece that contacts that star looking thing. They will wear and bend after a while and not allow proper engagement and travel to allow for a correct shift. Try replacing that and see what happens. Its a cheap part and not very time consuming to replace.

You think it's worth a shot? Looks like the part is about $10 at my local dealer. I guess I should try turning the star piece like thefox suggested. If I turn that myself, it should be like I'm clicking the shifter correct?

Rob

[f4tty]

thefox: great, thanks for the reply. I'm back in the Garage tomorrow so I'll pull it apart and have a look. Now that you mention springs it makes sense to me, I have another 125m and the shifting feels a lot more solid, the one that isn't working feels like pushing butter, so a worn spring sounds pretty on the money.

I'll have a look and see what I can find.

Thanks again.

[thefox]

You think it's worth a shot? Looks like the part is about $10 at my local dealer. I guess I should try turning the star piece like thefox suggested. If I turn that myself, it should be like I'm clicking the shifter correct?

Rob

Yes turning the star piece by hand is shifting the tranny, the star is attached to the end of the shift drum. If it changes gears by moving the star by hand then your tranny is good and there is probably a crack in the shifter arm or the drum stopper arm. Sometimes it is a small crack that only opens when a load is on it during shifting which makes it hard to see. It sounds to me like it is the shifter arm or stopper arm that is boken.