honda 125m transmission noises

[lilrogak47]

Hi, my name is roger. I just bought a 125m the other day and got it running today. The bike runs great and pulls in all gears. However, there is a noise coming from the transmission. I would describe this noise as something being loose and tumbling around. Of course, im not saying this is the problem but just what it sounds like. I took the sub trans cover off and inspected the high/low gears and they look fine. I also visually inspected the front sprocket, it looks fine. It makes this sound in all gears, including neutral. The faster you go, the more noise. Any help would be great, thanks.

[cummins91.5]

Do all the gears work? 125's have a common issue of breaking the shift drum stopper inside that disables 4th gear and makes it pop out in worst cases- Maybe a piece of that ended up in the gears now.

[lilrogak47]

Just did a test drive just to be 100% sure. All gears do work.

[Jason125m]

Might sound pretty dumb, but did you check your chain slack? That could be the source of the noise.

[lilrogak47]

Took it to a local repair shop today. They rode it for a few minutes, then put it on a jack. The bolts that hold the rear end in place were lose, so he had me tighten those and adjjust the chain slightly. None of this fixed it. It took the sub trans cover off as well as the gears inside. The gears in the sub trans are fine. I spun the tires with it jack up and with the sub trans gears removed, this way the main trans was not engaged. No noise. Put the sub trans gears back or, thus engaging the main trans again. Noise returns. So this excludes the chain, the sub trans, and pretty much everything outside the main case.

[lilrogak47]

Note: when I say "sub trans" I am talking about the high/low gears behind the cover that has the high/low switch attached. I have not torn any deeper than that, simply because I have never done it before. I downloaded the shop manual from dammit, some of it is kind of hard to make out, and most of the pictures don't seem to match my engine. Maybe because it is for 70-125, or maybe I just don't know exactly what im looking at. The repair shop I brought it to, as well as a cousin of mine, told me to just ride it until it don't ride any more. I don't really like that philosophy, because the way I see it, I don't want to make this small problem into a much bigger one. On the other hand, if I am going to have to possibly tear the cases apart to fix the small problem, then I guess it could be considered a big problem. What is your opinon on this? I just hope the solution does not require spitting the cases, because noone around here seems to want to take on the job...atleast not for under a few hundred bucks.
one more question. I have read on a few threads that a 125trx may swap over to my 125m. Is this true?

[sooper doodie]

what year? I just noticed you're in Walker, I live south of Livingston. You're going to have to split the cases. It's something in the trans. I have a bunch of 90/110 motors for parts. If you have a place to work on it I can help you with it. If i had a shop i would do it for you.

[lilrogak47]

It is an '84 model. I have another 125 and a 110 for parts, although they could probably be made into running bikes with a bit of work. I'm not sure what the story is behind the other 125, it came with the one I bought the other day. I appreciate the offer, and may take you up on that if worse comes to worse. Thing is, I don't have a shop either. Which is one of the reasons I don't really want to tear into this thing myself. I wouldn't mind paying a couple hundered bucks to fix this because the bike is just in great shape, other than this. It runs perfect, starts easy without choke even on cold mornings.

[tri again]

I've got a terminal shift drum stopper issue on a 125m.

Sounds like a 110 engine swap is the best for both of us.
if they'll swap.

Does yours sound the same in hi AND lo range?
Timing chain? easy fix / adjustment?

[lilrogak47]

Sounds the same, hi and low. Faster you go the faster and louder the noise gets. I would say maybe timing chain, but the sound is coming directly behind the front srocket.

[tri again]

Sounds the same, hi and low. Faster you go the faster and louder the noise gets. I would say maybe timing chain, but the sound is coming directly behind the front srocket.

I wonder if there's an output bearing behind the sprocket?
Can you access the manuals in the world class help section?

Most of the cool funky clutch stuff is under the cover with the clutch adjustment screw
and those cover gaskets are readily avail.
As I recall, all the power and shift drum stopper, clutches etc are on that side
and run their power to the opposite side and to the output shaft and sprocket you speak of.

I hope it's an easy fix.
Any metal in the oil? if so, what color?
silver paint?
or golden swirls?
Can you wiggle the output shaft and sprocket up and down?
like bearings are going bad?
Does it leak oil out of there?

[Howdy]

You have gave some info, but will need a little more to try and define the problem. The more info we have the better we can help.

Do you hear the noise when the motor is running and in netrual? If so does it get louder when you rev the motor up a little?

[lilrogak47]

Are you talking about the shop manuals from dammit!? If so I have the one for. 70-125. Did not notice any metal, paint or swirls in the oil. Outshaft doesn't move, only spins like it is supposed to. The noise is made even with the motor not running. Put it on blocks, spin the tires, here the noise. The noise is only made when the bike is moving, not stationary, the faser it rolls, the faster and louder the noise.

[Howdy]

Are you talking about the shop manuals from dammit!? If so I have the one for. 70-125. Did not notice any metal, paint or swirls in the oil. Outshaft doesn't move, only spins like it is supposed to. The noise is made even with the motor not running. Put it on blocks, spin the tires, here the noise. The noise is only made when the bike is moving, not stationary, the faser it rolls, the faster and louder the noise.

Is the chain well lubricated? Have you shifted the sub tranny to wear it is in the middle of hi/lo range ( sorta like netrual ) and spun the tires and listened for the noise? I would put it into 1st gear with the motor off when doing this so the tranny doesn't spin. If you still hear the noise it's probably a sprocket or chain. If you don't then my gut feeling is you have a gear with a chipped or broken tooth inside.

[lilrogak47]

Spun the tires with the switch between hi/low. It does still make the noise. I can also visually see the chain jumping in sync with the noise when I block it up and put it in gear. This does seem to go with your diagnosis of chain/sprocket. But, why is the noise not present when I completly take the hi/low box and gears off? This does not make sense to me.