Another Honda ATC 125m Transmission Problem

[wrecker200]

I have the opportunity to purchase another Honda ATC 125m. This one is a nearly pristine 1984 model. The owner states that it will only shift into first gear, other than that it runs good. Anyone know possible what may cause this issue. By reading all the different threads in these forums, it seems that the ATC 125m was prone to shift drum and internal shift linkage problems. I would like to consider purchasing and repairing this machine due to it's nearly immaculate condition, and it even comes with the original chrome Hondaline rear carrier and headlight guard. Hopefully it is an easy repair.

[Dave8338]

Without going in, it will only be a guess as to what's wrong with the trans. Could be as simple as a bent clutch fork or as complicated as broken gear(s) ect. If the price is right, I would get it and worry about what it is after you have it apart. Just my .02

[fabiodriven]

You probably won't believe this, but sometimes it's as easy as an oil change on the little Hondas. I've owned quite a few 110's and 125's and seen an oil change cure transmission problems on more than one occasion in the past. I would have trouble believing me if I were you, but I speak from experience. I will not guarantee this is your problem, but it doesn't hurt to try.

[kb0nly]

My guess as i have come across this so many times... Broken Shift Drum Stopper... Its the little spring loaded arm with a wheel on the end that clicks into the notches on the star looking end of the shift drum. Usually symptoms are it will pop out of gear or it will only go into first and you can't advance because the stopper isn't catching the shift drum for the next push of the shifter arm. Its a $10 part, just need a new one, case gasket, and a few tools, 20 min job tops and you can clean the oil screen while you got that side off as well. Also check the clutch adjustment before tearing into it just in case.

If your lucky its just the tip of the stopper arm broke off, in some really bad cases the boss that the bolt it pivots on is broken off the case, but if you can find all the pieces and they generally all just end up laying down in the side of the motor, you can get someone that can weld aluminum put it back in place, thats how i have fixed a couple.

[DasUberKraut]

My guess as i have come across this so many times... Broken Shift Drum Stopper...

If your lucky its just the tip of the stopper arm broke off, in some really bad cases the boss that the bolt it pivots on is broken off the case, but if you can find all the pieces and they generally all just end up laying down in the side of the motor, you can get someone that can weld aluminum put it back in place, thats how i have fixed a couple.

You mean like this kb??? A simple clutch swap turned into a nightmare for me tonight. Lookie what I found!!!

http://i172.photobucket.com/albums/w33/Duggalo/IMG_20130503_044850_592_zps1da13ed2.jpg (http://s172.photobucket.com/user/Duggalo/media/IMG_20130503_044850_592_zps1da13ed2.jpg.html)


Look how mangled it is! She was grinding away for awhile.

http://i172.photobucket.com/albums/w33/Duggalo/IMG_20130503_045042_000_zps29492304.jpg (http://s172.photobucket.com/user/Duggalo/media/IMG_20130503_045042_000_zps29492304.jpg.html)

So here's my question... Behind the boss in the case half, there's about 3 threads left to bolt into. Can I JB Weld this SOB back on and put a little bit longer bolt in. Or does it have to be welded? I only know a couple people who can weld aluminum and they are a couple hours away. I do have a spare parts motor with a solid shift drum stopper, but the head is tore off. Of course this would happen to me as I'm hurrying to get a rideable machine as the state trails are opening up now.

[barnett468]

Hello


Since you seem to be good with a camera I think it would serve you best to take a photo of the threads to get the most informed answer. If the "boss" this mounts to is no longer flat then you have a bigger problem on your hands.

[DasUberKraut]

Hello


Since you seem to be good with a camera I think it would serve you best to take a photo of the threads to get the most informed answer. If the "boss" this mounts to is no longer flat then you have a bigger problem on your hands.


Damm, Barnett... You're on top of my posts today.

I didn't even think about snapping a pic of the engine case. I loosely fit the cover back on put all my bolts back in place after picking up all my parts and whatnot. I was quite PO'ed to find the broken shift drum stopper. This is the second 125m in a row I get close to trail ready and then...BAM!!! Out of comission.

You can see the back side of the boss in the first pic. It still fits where it should. So it's not completely flat. It's just a tad concaved. But like I said, there are still a few threads beyond where this broke off. I will snap a pic after I sleep for a bit. I've pretty much convinced myself if I get the boss fixed, I'll order new clutch discs and springs to be on the safe side. Thank you for responding so quick to both threads barnett!!!

[barnett468]

Hello


Damm, Barnett... You're on top of my posts today.

Just coincidence but glad if any of my info helps.

xxxxx

I didn't even think about snapping a pic of the engine case. I loosely fit the cover back on put all my bolts back in place after picking up all my parts and whatnot. I was quite PO'ed to find the broken shift drum stopper. This is the second 125m in a row I get close to trail ready and then...BAM!!! Out of comission.


Yeah I sympathize with you’re plight, lol.

xxxxx

You can see the back side of the boss in the first pic.


Yes ok I understand now. My personal opinion unfortunately is ”you’re totally screwed” and I personally don’t see a way you can even mickey mouse it temporarily. I have fixed dozens of things like this.

xxxxx

It still fits where it should. So it's not completely flat. It's just a tad concaved.


Doesn’t matter.

xxxxx

there are still a few threads beyond where this broke off.


Not enough.

xxxxx


I will snap a pic after I sleep for a bit. I've pretty much convinced myself if I get the boss fixed, I'll order new clutch discs and springs to be on the safe side.


Yeah it’s cheap insurance.

xxxxx

Thank you for responding so quick to both threads barnett!!!


No problem you’re welcome.

xxxxx

If you decide to weld it I can give you a couple suggestions but it is pretty straight forward.


Regards

I’m pretty sure you will get someone saying JB weld will work or you have enough threads no problem or just use “Super Glue”. I simply suggest you do what makes the most sense and not the thing that is the easiest like many others I have seen do unless they are one in the same.

[kb0nly]

Yep, your 125 suffered the common shift drum stopper boss failure.

That looks exactly like one i fixed... I removed the remainder of the boss from the bolt and the stopper arm, then get a longer bolt and use that to bolt the broken piece back to the spot on the case and then have it welded, after its welded and completely cooled just spin that bolt out that was used to line it up for welding and then replace your shift drum stopper arm. The bolt has a special shoulder on it, so you can't just use a regular bolt to replace it. However, i have been thinking a slightly longer bolt with a small bushing on it for the arm to rotate on would help strengthen it because the factory bolt doesn't go through all the threads and puts a lot of stress on that boss.

The ones that i have had welded haven't failed yet, but i got a guy here that can weld aluminum in his sleep. I have been thinking of trying some of those alumiweld rods on one sometime, but not sure how effective it would be since its about the same as putting on JB Weld, its a surface repair. Welding them back actually melts the metal and fuses it back on, lots stronger.

I know one guy that JB Welded it on, but he also split his case, made a longer bolt and bushing setup, and put on a nylock lock nut and flat washer on the inside of the case, so its effectively bolted through the side of the case rather than just the boss! I doubt that one will every break again.

[DasUberKraut]

The other half of the puzzle...

http://i172.photobucket.com/albums/w33/Duggalo/IMG_20130503_142651_856_zps5f896010.jpg (http://s172.photobucket.com/user/Duggalo/media/IMG_20130503_142651_856_zps5f896010.jpg.html)

[kb0nly]

The only way your gonna fix that is welding... Get a bolt thats a smidge longer or one close enough so you can make one the right length to grab those threads, have the stopper arm on so you can make sure its lining up with the drum and its flat, then have someone weld it, thats about the only way i can see you fixing that unless you split the motor and do some custom fabrication to it.

Wish i could offer a quicker easier solution but thats a repair that i have done four times now to 125's and i can tell you JB Weld and other solutions don't work, if they do they don't hold up long. The stopper arm spring puts a lot of torque on that boss, no adhesive is going to cut the mustard there.

[DasUberKraut]

Welding does last once repaired? Is that a 6mm bolt?

Supposedly my roommate knows an aluminum welder a few miles away.

I really don't want to attempt a head swap a couple weeks before the trails open.

[kb0nly]

Yes, i have been through that 4 times now, and all of them were welded and they have lasted and lasted. One of them i took apart last year to do clutch work on it and it looked just as good as the day it was welded. If you get a welder that knows what he is doing with a TIG welder and aluminum there is no reason it won't work. I'm almost positive its a 6mm, but i don't have any spares left in the drawer to look at.

Just show the guy thats gonna weld it how its critical that its directly up and down so the stopper arm lays flat, otherwise it could bind a bit, you could always bend the shift arm just a smidge if its not perfect though so don't over think it. Have him lay in a nice weld all the way around and tell him to build it up a few layers to get to good material on the case and the piece. You might also want to buffs the areas to be welded with a wire wheel, but he should know enough to do that.

I got a welding shop here, the guy is an absolute wizard when it comes to the TIG, i have had him weld up aluminum tubing for building antennas, even the fairly thin stuff, he can do it no problem without blowing through.

[tri again]

Just 4 the record, I have a busted one just like the pictures.
I'd bet the orig bolt setup didn't allow the shift drum stopper to
pivot easily.
I should find my aluminum guy.
He could weld 2 soda cans together.

[kb0nly]

Just 4 the record, I have a busted one just like the pictures.
I'd bet the orig bolt setup didn't allow the shift drum stopper to
pivot easily.
I should find my aluminum guy.
He could weld 2 soda cans together.

I agree, i think sometimes they can get stuck, and then the rider jabs the shifter hard and pop.... I had one that was loose on the shoulder of the bolt, and one that was pretty snug, so you have to check to make sure the shift stopper arm pivots nicely on the bolt.

[DasUberKraut]

To me it seems like an over tightening issue.

[kb0nly]

Its not overtightening, you can't. The bolt had a shoulder on it that sits on the top of the boss, and you sure can't crank that bolt down too tight, i have broken two of them not being ginger with them. Below the shoulder on the bolt there is a section of no thread before the thread starts thats really skinny and makes the bolt weak. They aren't to hard to twist them off for sure!

[DasUberKraut]

Oh. Yeah. I haven't pulled the bolt out yet. It's been crappy out with the fresh snow. I'll have to dig through the bolt bucket and find a longer one for welding.

[kb0nly]

Thank god the snow is finally done here....

If i still had a spare i would take a picture of it.

Nevermind finally found it on Dr ATV, i just had to look through my old invoices to find the part number.

http://dratv.stores.yahoo.net/shdrstpibo2.html

Its like they built in a failure point with that weak area between the shoulder and the threads.

[jeepvolks]

I'm chiming in because I'm searching for the pieces you guys are speaking of. I've taken off the left side cover where the clutch is housed. Is this the side to be working on? Also, I noticed strange wear on some phillips head screws...
168773

[tri again]

I'm chiming in because I'm searching for the pieces you guys are speaking of. I've taken off the left side cover where the clutch is housed. Is this the side to be working on? Also, I noticed strange wear on some phillips head screws...
168773

as I recall, I had the same sick feeling when I took mine apart.
What in the world was loose and grinding against those p. head screws.?
I just buttoned mine back up awaiting a thread like this one but mine looks the same.

[tri again]

Thank god the snow is finally done here....

If i still had a spare i would take a picture of it.

Nevermind finally found it on Dr ATV, i just had to look through my old invoices to find the part number.

http://dratv.stores.yahoo.net/shdrstpibo2.html

Its like they built in a failure point with that weak area between the shoulder and the threads.
Hard to believe someone came to work with this great idea, which is ok but then,'
a committee of 12 AGREED with them.
I wonder what the 90/110's look like as they don't seem to fail as frequently.

[DasUberKraut]

The shift drum stopper is behind the primary gear to the upper left of the case. Primary gear being left of the clutch assembly.

Mine was literally just sitting on top of the primary. You can see it ground it down nicely.

You need a spanner tool to get the clutch assembly off and snap ring pliers to remove the primary gear.

[Howdy]

I'm chiming in because I'm searching for the pieces you guys are speaking of. I've taken off the left side cover where the clutch is housed. Is this the side to be working on? Also, I noticed strange wear on some phillips head screws...
168773

Those screws look as if they came loose and wore on something. And that is never a good thing. Look at your side cover and all other parts for wear marks.
Howdy

[jeepvolks]

I got it all apart and the lever was both bent and a little split; probably should have taken a photo. Anyway, I ran up to work and welded it back (just enough to make it sturdy and put everything back together. Not sure why, but those screws that were shaved looked like button heads. There were holes countersunk into the piece they secured so I just bought some that had the matching counter sunk heads. Rides and shifts great! No missing gears, popping out of gear or hunting for neutral. Feels like there might be
just a tad too much tension on the lever so I'll order a new one to put in there for good measure. Thanks to all and I appreciate you sharing your knowledge :)

[DasUberKraut]

Glad you had success jeep! :beer

I found a longer bolt to hold my stopper boss in place for welding on the first try in the bolt bucket.