atc125m sub-transmission problem

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Hello Im new this forum and would like to get to know more about the atc's. I currently own a ATC250es and I Just purchased a ATC125M today for $100.Its all there but is missing the headlight and battery. I saw it on Cl for 150 and I talked the guy down to 100, the plastics are all there and the seat cover is a little torn but it has brand new tires on it and the guy gave me a itp wheel with a new tire on it. It fires up first pull but the reason he wanted to sell it he said he was ridding it and it kept popping out of gear. I pulled the hi/lo cover off and the countershaft had 2 teeth missing I don't know why they were broken but the other gear inside looked fine.I found the shaft on ebay for 75 I will need it but does anyone ever heard of this happening or what else should I check out. Also I will have to replace the side cover spacer because when I pulled the hi/lo cover off the backside of the cover was broken where the chain runs behind it.Either the chain came off and broke the housing then hit the gear I don't know but something put that gear in a bind.I did ride the wheeler but it was making a popping noise but I didn't ride it but a couple of feet I didn't shift the gears. Thanks for any help I cant wait to fix for my Gf to ride.will post picks when the weather gets a lil better

[DasUberKraut]

I have two spare 84 125M headlight assemblies. Make me an offer on one or both if you're in need.

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what would you have to have for the headlight I don't have the wiring or bulb

[DasUberKraut]

Like I said. PM me an offer. I can send pictures. Both the assemblies I have are complete to my knowledge. Headlight mounts, and wiring included. I can't verify if the bulbs are good.

[kb0nly]

If its popping out of gear i would also bet you have a bad shift drum stopper on the right side, thats as common as gasoline on the 125M... LOL

I would agree with your diagnosis on the sub-trans, probably a chain slap but someone could have hit something too. The teeth probably got damaged from a piece getting in there and getting caught between the gears while moving.

But the problem with the sub trans would not cause the transmission to pop out of gear, thats the commonly known shift drum stopper problem.

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I hand shifted the gear lever today the neutral indicator was turning like it should but that probally don't mean anything. ive got another side cover spacer but ive only found the gear that has the teeth missing on ebay I just don't want to replace that piece and the same thing happen again. if you think it would be ok to change that and see if it pops outi will try that but I don't see any other reason that that cover could have broke like that other than that chain being loose. the chain cover is off and I don't see a roller for the chain or guide. if someone has a picture of their setup I would appreciate it. Im glad to have found this forum thanks to all that have responded.

[DasUberKraut]

Drain your oil and pull the right side cover off. You'll see if your shift drum stopper is toast or not.

[kb0nly]

The neutral indicator will move and the trans will shift through gears when its not running, but when you have it running and moving it will pop out of gear because the shift drum can turn independent of the shifter because the stopper doesnt, well, stop it... LOL

I agree with him, drain oil, pull cover, and inspect it. You might as well get a right cover gasket and clean the oil screen in there as well, its the basic oil filter that these have and its under the right cover towards the front. The shift drum stopper is under the right cover upper left corner, looks like a metal L-shaped piece with a roller on the end of it, that roller goes into the slots on the star shaped piece on the end of the shift drum. Just be careful when you take the cover off that you don't loose anything, the little oil tube and spring in the clutch adjuster likes to drop out, lay the whole trike on its left side so you can pop apart that side without stuff falling around.

http://dratv.stores.yahoo.net/268n.html

Example of the stopper. They are available brand new if yours is broken. Usually it breaks at the L bend and the roller tip is rattling around somewhere. To replace it isn't that hard, but you will need a clutch nut socket and snap ring pliers to get the clutch and the main gear thats over top of it off. The service manual for the 125M is on my manuals site, link below in my signature.

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thanks for the info ima order a gasket kit if the stopper isn't broken then I should be ok on that side but when I replace the left cover will I be able to check out the gears. the guy sais they was ridding it and it just stopped but he didn't tell me the side cover was broken that's why he must have taken 100 but 3 wheelers are hard to get cheap in nc I bought my 250es for 250 the plastics were cracked and was the 125m but I tape the top of the plastics to hold the cracks into place and use a solder gun to melt the underneath so I don't have to use zip-ties but it runs great but that's kidda wired to have to take a side cover off for the oil filter screen. So I will check the parts that u mentioned and if there ok then I will assume the chain flew off and cracked the cover and broke that gear and I should be ready to ride. I might take it apart and send pics and see if someone or you can tell me if the parts look good thanks kbOnly

[kb0nly]

Ok sounds good, post up some pics after you get it apart and of the sub trans damage, would like to see what your dealing with. A picture is definitely worth a thousand words!

The smaller motors, 90/110/125 all have an oil screen inside under the cover. Guess they figured that way you had to open it up and clean it out when you cleaned the screen. I generally clean the screen in them every 2-3 oil changes depending on how it was used, in a lot of dirt or not, etc.

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I received my sub trans assembly today they are hard to find I got the whole setup off ebay for $15 better than the one gear for $70. I have to power wash it in the mourning so I can start on it I will get up some pics tomorrow and the damage that was on it when I got it.I have a few questions I took the bad gear in the hi-lo housing and I put the cover back on but when I crank it I head a rattle from the right side it sounds like more like a clicking sound it does it sometimes. I will remove that side cover after I wash it off. I downloaded the manual and just wanted to know if the stopper doesn't have any damage how do I check the drum and do I need any special tools to remove anything. I still have to get the left side cover where it snapped off and do I need any special tools when I replace that cover?

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here are the pics of the engine I tore the right side cover down and it looks very clean the oil was nasty but here are the pics of the damage to the sub trans after I cleaned the broken side cover I seen deep scratches so I know the chain had to break it. I will post pics of the wheeler when I get the engine back in. The timing chain and the gears that I could see looked good and no damage. Im going to take the engine to a ctv mechanic because the Phillips head screws look like they have been taken off before but some look stripped so I don't want to take a chance of making it worse.185572185573185574185575185576

[kb0nly]

Wow thats a crazy sub trans failure!! Definitely a chain failure at speed though i would bet on it. Make sure you put a new chain on it to! LOL

As for special tools, the clutch nut socket and a snap ring pliers is all you really need to take apart everything on the clutch/right side. The clicking rattling sound could be the broken off piece of the shift drum stopper, i had one do that as well. It just rattles around in there until you fish it out or it gets caught in something and really destroys the bottom end.

For getting those case screws out the best friend you can have is a handheld hammer driven impact driver. Looks like a big fat screwdriver that you smack with a hammer and it gives impact and twist to remove the screws.

If you got some buggered up ones just replace them with bolts, they are metric of course, but not hard to get. I forget what size they are, 6mm or 8mm... I would have to dig out the box i have of them, i bought a box of the right size bolts from the hardware store and every time i rebuild one of these i replace the screws with metric hex head bolts. So much easier for doing maintenance and repair. They are a flange head bolt and work great.

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185693185694185695 didn't see any parts broken inside nor any metal pieces inside the cover and parts look clean as did the oil screen.

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does anyone think I can take the snap ring off the gear to lift it up enough to see if the stopper is damaged. The guy I got it from said that the sub trans gear was the only problem when I got it he never said the trans was damaged? By the way the internals of the engine look and it didn't smoke and ran at idle and throttle response I think I maybe ok just don't want to pay 30 for a clutch removal tool but I don't want to put it back together broken Was also woundering will a 110 front sprocket fit the 125 they are 1 tooth up and cheaper