139QMB Gearbox Bearing Replacement Part 2 (GY6 50cc Scooter)

Part 2 (of 2) showing the replacement of the gearbox, aka final drive transmission, bearings in a 139QMB / GY6 50cc scooter. Part one covers disassembly and removal of the bearings. Part 2 covers installation and reassembly.
Part 1 :
• 139QMB Gearbox Bearing...
The scooter is a 2013 TaoTao ATM50-A1.
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#GearboxBearings #ScooterDIY #ScooterRepair

[@garryoleary1672]

Excellent detailed narration from an obviously well qualified experienced mechanical engineer - Thank You

[@crosbytristen1153]

I guess it is quite randomly asking but do anyone know of a good place to stream newly released movies online?

[@JBetoRodrigues]

This is SURELY one of THE BEST videos I've seen of HOW TO DO IT YOURSELF. Probably the BEST . Really good . Thank you so much . GREAT JOB

[@oscr_zen]

thought the same thing

[@cwelliver1985]

I accidentally over torqued the transmission drain bolt on my Honda Elite scooter and subsequently cracked the transmission cover. I thought I was screwed until I found this video. I ended up buying a new transmission cover, bearings, and oil seal. The installation was a piece-of-cake thanks to this video. Thank you so damn much, I owe you a beer!

[@FrenchValleyAirport]

I don't even own this scooter or anything like it, yet i watched the entire video because your technique is so interesting.

[@sam-dn9hr]

Thank you so much for this great tutorial! My Honda Vision bearings just died and the shop has quoted more than the bike is worth to fix so I am going to follow your tutorial and Im now confident that I can fix it :)

[@49ccscoot]

Good luck with the repair!

[@gulfsurfco]

Excellent video quality! Excellent instructions too! Thanks!

[@DirectorDavoPaul]

BEST HOW TO EVER!!

[@IvaniaHenriquez-gz9dt]

Hope I can find a motorcycle mechanic that in the future my X-pro fiji 200 can be fixed . Learning with you about scooters and online.

[@joannamiller8421]

it is nice to have all the tools,for a job like this also noing how to put back together

[@VTwin4Christ]

Great job! Helped me rebuild a gx150 Yerf dog gearbox. Exactly the same but reversed. I don't know how much folks charge for a gear kit for scooters... but I got all bearings, seals, gears and gasket from Buggy depot for 85 bucks.

[@smigitgettit4162]

I've always look for your videos you're a great theacher

[@kaikruner6971]

Brilliant !!! this is exactly what i was looking for. Cheers

[@CandyFishRave]

That's great news thank you so much!..

[@DavidKnight30175]

Great video, I found some things I where I had messed up, when putting mine together. I also found somethings to try on the next build.

[@just4kicks950]

Your vids are awesome & if I had 30% of your knowledge on scooters ! I would be happy much appreciated . Salute my friend 👍👍💯🌟😎

[@lawrenceguinto7260]

Do more maintenance videos thankyou . I suggest how to tune up scooter , change spark plug etc

[@colinfoote8683]

very well done.

[@stevemogil2387]

Great video, well done

[@49ccscoot]

Thanks.

[@Lacider]

Comprehensive and helpful, good job. How about a vid on what to look for in a used scoot, or if even a used scoot is worth it.

[@hinano316]

Awesome vid. Thanks!

[@rikityrik]

Exceptional how to demo. Couldn’t think of anything you could had done better. Very impressive and thankful for the time you took to film and post this. I’ve actually watched this two part video a few times now. It’s really thorough. You thought it out perfectly. I’m having a time and a half with the middle 6201 bearing. I’ve used two different pullers, and applied fair amount of heat at the case around the bearing. Thing seized like nobody’s business. Thinking of seeing if I can find a new plate minus bearings. Not necessarily looking for advise just aggravated. 😭 There’s always one, isn’t there. lol. Anyways love your videos man.👍 Happy Thanksgiving.

[@49ccscoot]

Try the bread or grease method. Look that up here.

[@rikityrik]

@@49ccscoot thanks, i’ll check it out!

[@rikityrik]

I got it out. Had to use a bit more heat than usual but it finally came out. Thanks again for your reply. Was about to try your advice it if it didn’t work after this last time.

[@robertfreund7525]

Thank you

[@jasmintuzla1675]

great video.....well done.

[@49ccscoot]

Thank you.

[@vickyenoch4340]

great video..

[@CandyFishRave]

Thank you so much for this video it's awesome I needed to no how to get to the gasket thats on the gearbox that you put back on thankx so much by the way we're do you buy parts like that gasket to the gearbox I bought a new moped like this one and I inspected it and so far I can see there is oil coming out of my gearbox from were the gasket is at any help would be great provenpowersports Is no help at all thank you so much for all your vids as well there of great help to all of us!...God bless

[@49ccscoot]

CandyFishRave You can buy whole gasket sets usually pretty cheap on eBay. That's generally what I do, then I have spares for others as well if needed. I use PFS regularly. www.partsforscooters.com/?partner=49CCSCOOT Also ScrappyDog has a bunch of stuff.

[@jeffmee763]

And don't forget the oil will know now don't we good job.

[@Jesus5551000]

139QMB Gearbox Bearing Replacement Part 2 (GY6 50cc Scooter)

[@vr6u35]

Thank you.

[@truthseeker104]

Great tutorial! How much gear noise should be coming from the gear box when the engine is off and you turn the back wheel by hand. A mechanic who recently changed the tyres on my 50cc Peugeot Kisbee said he thought there was a problem but I always recall some gear noise when turning the wheel by hand or moving the bike, so not sure if a repair is necessary at this time?

[@49ccscoot]

Hard to quantify how much exactly. It's not silent.

[@truthseeker104]

@@49ccscoot Thanks for replying. I don't recall it ever being silent, it sounds more like a cog noise as opposed to a bearing noise. You can't hear it when riding along and there hasn't been any adverse effect on the performance or economy of the bike. I have always used good quality gear oil of the correct specification. There is no play in the wheel axle or rear pulley shaft bearings. So at the moment its probably better to leave it unless it gets worse. Watching your tutorial, some of the cogs look quite small so I guess will be more prone to wear, especially with a heavier rider like me in a relatively hilly area. Anyway again thanks for the tutorial and reply to my message!

[@49ccscoot]

@@truthseeker104 What you describe sounds normal to me. If you trust the mechanic, then maybe there is an issue. You can always drain the oil and see if there is anything that looks unusual. Metal flakes and that sort of thing.

[@truthseeker104]

@@49ccscoot I drained the gear oil recently (last week) and it was ok, nothing strange about it no metal flakes. I think I know what may be the issue. There is a noise when moving the scooter, or turning the rear wheel (with the engine off), there is a similar noise when the bike is idling but not moving. There is no noise when the bike is in motion, so I am guessing it may be the bearings associated with the clutch and pulley, which will be stationary when the clutch is engaged. I am due to replace the belt and service the clutch soon, so that will be a good opportunity to inspect the bearings. I tried to take the clutch bell off last week when I removed the CVT cover but it was stuck. Anyway will have a look again when I replace the belt. Other than that the bike is running well at present. Thanks for getting back to me.

[@itaizrihan5701]

wow awsome video

[@CarstenLorenzen12V]

Great video, as always! Where the bearings already gone bad, or did you just feel like doing a tutorial? :)

[@49ccscoot]

Both countershaft bearings were bad. I was getting a rhythmic vibration at about 30-37MPH. It's still there, but faint, so there's probably something else going on.

[@49ccscoot]

paraglidermx Mine turned out to be largely from the threaded area on the drive shaft being bent slightly.

[@49ccscoot]

Should work.

[@jeffmee763]

@@49ccscoot Probably needs oil ? I do enjoy your videos the ones on the tao gy6 50cc were well entertaining good on you.

[@jeremyturner6173]

Love watching these very informative videos. Would like to know if the bearing numbers match up to a honda elite 50cc

[@49ccscoot]

I've never messed with the Honda engines to tell you for sure.

[@jeremyturner6173]

@@49ccscoot thanks. If I need to know anything that I. Not sure of I watch your videos. Most in depth videos I can find. Also explain very well

[@49ccscoot]

@@jeremyturner6173 Thank you! I always like to hear that my videos help people.

[@kscotthux162]

If I need to just replace the rear axle, do I need to take the whole gearbox apart? I have a jonway 2006 YY150T-12 SCOOTER

[@49ccscoot]

Yes. You can't slide it out any other way. Might as well check/replace the bearings while you're in there.

[@chrislavalley4062]

I have a bad bearing on the clutch shaft

[@chrislavalley4062]

Your awesome

[@chrislavalley4062]

I have no press and can't think of a way to get bearing off clutch shaft

[@artur855]

super

[@alexh.5579]

shouldn't there be a spacer between the output shaft and its bearing? (A aluminum spacer fell out when I pulled my gearbox out don't know where it came from) Thanks!

[@49ccscoot]

My 139QMB didn't use a spacer, but my 1E40QMBs regularly have a thin shim on the intermediate shaft, between it and the large case.

[@billyjonesmiller]

But how do I get de bearings out

[@robertallen80]

why the 02 sensor is this efi if so i would like a link to purchase

[@49ccscoot]

It's a wideband for tuning.

[@Stoneforth]

In my case two of the bolts were smaller than the rest. Lots of little differences on these

[@49ccscoot]

Consistency certainly isn't a strong point on Chinese scooters. In any case, the bolts can be inserted into the holes before any are tightened. At that point you can look at how much of the bolt is sticking out to tell which holes need longer or shorter bolts.

[@tamaramartina3751]

Stoneforth

[@ertelenmisdusler7235]

Doesn't heating the bearings in the oven damage their natural structure? I know that it can withstand a maximum temperature of 110°C.

[@49ccscoot]

SKF's info said 257F max for heating them.

[@ertelenmisdusler7235]

@@49ccscoot Is your oven temperature unit Fahrenheit? I'm sorry, I don't know how to speak English very well.

[@49ccscoot]

@@ertelenmisdusler7235 Yes. My oven is F.

[@newtechnology2399]

Please someone explain me if I rotate the wheel of the scooty bell casing start rotation is the power goes into the crankshaft or not ? How CVT clutch works

[@49ccscoot]

The crank turns the variator. The variator is linked to the rear pulley by the belt. When RPM of the rear pulley is high enough, the clutch engages and transfers power to the gearbox and on to the wheel.

[@newtechnology2399]

Suppose I rotate the only rear wheel of scooty by hand wheel rotate which rotates the bell casing bell casing consist of clutch CVT ok. Is the that CVT belt will rotate or not ? If I put motor on rear wheel of scooty power goes into the crankshaft of engine or not ?

[@49ccscoot]

Never tried it. I guess you could get the engine to spin, but I'm not sure how well that's gonna work.

[@GrumpyUnkMillions]

The 'shoes' of the centrifugal clutch will not rotate,thus no link from the bell & belt tp the variator.

[@tamask401]

Hy . when you install the primary drive shaft, how long did you heat the bearing housing before? he doesn't want to slip into me like you do. and I dare not knock.

[@49ccscoot]

If you have an infrared temp gun or other capable thermometer, heat to around 250-300F. Without those, I've heard some just heat till any oil residue on the case starts to smoke or spit will sizzle on the cases for a simple trick.

[@tamask401]

it was possible to insert the bearing, but the internal shaft had a minimal backlash. The other bearings have also been replaced, but the gears also have a minimal backlash. What could be the problem?

[@49ccscoot]

@@tamask401 These are all original gears? Just thinking maybe something isn't matching up properly if you're trying to change ratios.

[@tamask401]

@@49ccscoot the same gears that I took out came back. of course, new bearings, but there is still a little backlash. I don't know what it could be.

[@49ccscoot]

@@tamask401 Is it together enough to roll it and see how it feels? Maybe it's OK for use?

[@Bulgdoom]

Great video man, just wondering tho. Were ur original bearings bad and if so what caused that? I was looking at a very cheap scooter fwith 15,000 miles and was going to get a 100cc big bore kit which people say eats crankshaft bearings potentially, and probably guessing the transmission gear bearings would be eaten too after this many miles.

[@49ccscoot]

Original bearings, some of them at least, were bad. I later found a bent clutch shaft that had been causing a lot of vibration. At 15,000 miles I'd expect it to be in need of a lot of things and plan a full inspection. The 100cc kits usually kill the conrod big end bearing. If you wish to use a big bore kit larger than the 72cc/47mm you should consider an aftermarket crank like the Naraku HD. There are stroker cranks available as well from Hoca or Scooters To Go or ScrappyDog.

[@Bulgdoom]

***** I was hoping to replace only wear parts, performance crank costs more than the scooter and if bearings alone can fix problems then no need for a new one. The only problem i foresee is the gearbox since most people don't know about the oil there. Carb is mostly metal other than diaphragm. Its a 2011 so plastics should be fine, someone just rode it a bit.

[@49ccscoot]

The big end bearing is a big job and by the time you find one and then get the main bearings and deal with trying to press the crank apart and get the gears back on right so the timing is correct it's much easier to buy a new crank. You could skip the aftermarket crank and go stock replacement and use a 72cc kit instead of the "100cc" that actually about 81cc. It would be much more likely to last that way. I wouldn't expect it to last if you put any BBK on a 15,000 mile stock Chinese crank. It may, but don't be surprised if it doesn't.

[@ryanbb3024]

I did all this and still can't move the tire when all is installed. And suggest would be helpful

[@49ccscoot]

Take the wheel off and make sure the brakes aren't stopping the wheel. If that looks good, maybe there isn't enough clearance in the gearbox. Could be a thinner gasket or the wrong shims on the countershaft or something like that causing it all to bind up. If you can loosen the gearbox bolts enough to allow slight movement of the gearbox half and suddenly everything moves freely, then it's a clearance issue.

[@MetroLinerXLZ]

Are the the bearing sizes the same for the 150cc GY6 engines?

[@49ccscoot]

+MetroLinerXLZ The process is pretty much the same, but the bearings are not the same. www.partsforscooters.com/?partner=49CCSCOOT sells a whole bearing kit for the GY6 and lists the bearings. It's part # 164-299 there.

[@yannkitson116]

I replaced the bearings in my 150 cc GY6 and I used the following 6 SKF bearings: transmission housing 6301-2RSH, 6002-2RSH/C3, 6004-2RSH/C3, / transmission cover 6204-2RSH/C3, 6202-2RSH//C3, 6203-2RSH/C3. Remove the seals so the bearings look like the ones they replace. I recommend removing the old bearings before you buy the replacement ones so you can double-check the sizes. The price for the parts where I live was in OCT/2016 60 TL for the bearings, 47 TL for a complete set of new shafts and new gears, 8 TL for dry ice. Total price 115 TL ~ 37 US dollar, sound of a silent transmission... priceless :)

[@williamanguyen]

my bearing have the plastic cover on one side, is it ok to leave them all on or do I have to take them out? thanks!

[@49ccscoot]

If they're not facing the outside (like on the drive shaft toward the CVT or the axle toward the wheel) then I'd remove the seals and let gear oil lube them.

[@simons1084]

4:29 What is the seal number?

[@49ccscoot]

27 42 7

[@kingelvis94]

Hey man i have watched all the toa toa videos and have finally just bought one i know they will need work to be dependable but if u could make a video stating all the mods that are worth doing for performance (most bang for your buck also). also i might have missed it but is a different exhaust a bad idea or not worth it? One last thing i live in NY and my roads are very hilly is 4.5 sliders the best for climbing this kind of terrain? Thanks for making these awesome super high quality and informative videos will let all my scooter friends know about your channel!

[@49ccscoot]

4.5-5g should work. 5g is really popular and I think most people would be happy with those vs stock. It would be a while before I could do a good vid on a bunch of mods, but I can tell you that a big bore kit offers the most bang for the buck to start with. 47mm kits are easiest on the engine, but still give a good boost in power. You would need to tune the carb with it and perhaps change roller/slider weight. Some BBKs are similar in price to exhausts, but the exhaust will not compare to gains with the larger bore.

[@kingelvis94]

wow thanks man will look into it thanks for the fast reply!!!

[@julianarodriguez3635]

What kind of grease did you use on the seal let me know thanks

[@49ccscoot]

I use a synthetic general purpose grease. Mobil 1 is what I use most of the time.

[@itaizrihan5701]

can u do a video on how to replace the clutch bearing? my bearing dosent turn smoothly on the clutch shaft, there is some friction between them.

[@49ccscoot]

Done! kzbin.info/www/bejne/aJeQaISVZayFd6s

[@itaizrihan5701]

@@49ccscootty

[@Meinstantics]

Hey 90. My middle gear doesn't have a bearing, just a circle slot and it appears to have had a spacer on both ends, one end is a rubber spacer, one is metal. I can't remember which end each spacer was on. Do you have any idea which one should be used on what end?

[@49ccscoot]

I'm assuming they are different thicknesses, so my first thought would be to try them and see which align the gears best.

[@steveh6266]

I have a howhit 150cc gy6 in my boys yerf dog spiderbox. I changed all bearings except the output shaft, it seemed fine, I think having a deal helped. Everything why well, or so I thought.... Once back together the go kart will roll say 10 inches forward and lock up and the same backward. What could I have screwed up?

[@49ccscoot]

+Stephen Hughes Some of the ATVs have a totally different gearbox and reverse, which I'm not used to, so I'm not sure if there could be anything else at play with those. My first thought is to be certain that you didn't lose any spacers and they're in the right spot. Usually it will feel tight all the time though if spacing is a problem.

[@steveh6266]

+90GTVert I made a stupid error hurting prong it all back together... On my output shaft there is a snap ring, instead of putting it in the grooves on the splines I put it after the splines. That's what I get for rushing!

[@ruali8847]

Hey, So I checked everything out with the multimeter and all electrical parts are working. I removed the cvt cover to look at the variator to see if the gearbox is engaging it. It does engage, but for some reason the variator is extremely hard to spin. I almost can't turn it with my hand. When I kickstart it, it's still trying to turn over but I think the crankshaft/variotor is really tight for some reason. I double checked the valves after watching your tutorial and they had 1/4 inch gap. I tightened them down to .002 according to a 139qmb manual spec sheet I came across. This is the best the scooter has tried to start so far. Any suggestions on how to loosen up the crankshaft/variator so it can spin more freely. Thanks in advance.

[@49ccscoot]

Squeeze the rear pulley so there's slack in the belt and then see if the crank turns easier.

[@paulflood4420]

Do i use c3 or normal bearings

[@49ccscoot]

I used standard.

[@nodleydelmas2561]

Where can I buy scooter parts?

[@49ccscoot]

ScooterTuning.Ca and PartsForScooters have been good for me. For bearings and such, I usually look on eBay and amazon to see where I can get the best price on well known bearing brands.

[@quackerz312]

i dont get how you got your bearings on in the cvt,i used the heat gun and had it on there for at least 4 min and my bearings were in the freezer and by the time i got it on level and pushes it would stop a quarter way through. i used a socket and they wouldn't go down all the way only went down a tiny bit

[@49ccscoot]

+Rich Noble Try using a temp gun to see if the cases are getting up to at least 250F before you try to install the bearings. Also, make sure they are going in straight.

[@quackerz312]

+90GTVert yeah i was thinking about seeing what temp it would be at with the heat gun. and i try and get it straight in with gloves on but its a little harder. how long do you keep your heat gun on the targeted area for?

[@49ccscoot]

+Rich Noble I don't time it, I watch temp. It takes some time with cases though. You may not be up to temp in the 4 minutes you mentioned.

[@quackerz312]

+90GTVert yeah didnt think it would be with 4 mins, ill be taking a try at it today and see how it goes. ill let you know if it goes good or bad. thanks again!

[@49ccscoot]

+Rich Noble Good luck!

[@brandonblank891]

Is there a certain gear set that i can install that will give me more pulling power on hills? I live in the mtns of nc and my commute to work everyday is 18 miles mostly uphill. I have replaced the clutch with a standard mmk. It has a 72cc bbk glixal variator and 4.5 gram weights. Right now it is doing ok will pull at 25 to 30 uphill. Does about 40 45 flat. I weigh 230lbs also. Can u give me any advice for more torque? Its a 2016 taotao/ jazzy with a shortcase. Any advice will be appreciated. Also how do i check the gear oil level

[@49ccscoot]

Naraku at least used to make a gear set that was better for acceleration but lowered top speed potential just a little. Not sure if they still make it, but you can check if anyone does. They were 52/14. It sounds like you're doing pretty well now. These are tiny engines to be pulling people uphill. A lot of people don't even like to ride 250s in the mountains. Keep the carb in tune and play with the weights a bit to see if you can find anything that works a little better for your needs. Try .5g heavier and lighter for example and see what each does for you. Can't really check the gear oil that well. Basically you can see if it's about up to the bottom of the fill hole. If not, you can add some. I just watch for leaks and if I'm in any doubt I change the gear oil because it's such a small amount.

[@brandonblank891]

@@49ccscootI cant thank you enough for the advice. Its been a real struggle with this thing. Its litterally my livelyhood til next march lol. I really enjoy your videos. You are very clear and direct. You know your stuff. But back to the scoot. I dont care so much about speed as i do gettin up that mtn at a decent pace. Can you give me some advice on clutch springs? Should i got with higher rpms or lower?

[@brandonblank891]

@@49ccscoot one more question also. I have a metallic circular whining noise that sounds like its coming from behind me at differnt times. Would it be because im low on gear oil or are those bearings going bad?

[@49ccscoot]

@@brandonblank891 Could be all sorts of things. You may need to put it on the stand and see if you can make it happen to tell where it's coming from better or pay attention to conditions when it occurs to give clues to where to look.

[@brandonblank891]

@@49ccscoot ok will do. Im sorry to keep askin questions but ive been lookin for someone with ur level of expertise. Ive been given some bad advice. Ive only been ridin since march and Im learning as i go and i wanna know how to do things the right way i dont like to half ass my vehicles. This is my first scoot. I just bought another 50 just like this one just rough cosmetics and its been wrecked. Ibpaid 200 cause i needef a ride quick lol had a belt break and needed to wait for one in the mail. If i go with the 4.5 or 5 g sliders do i need to go with higher rpm springs? On my way home everyday i am able to get some serious speed up goin down that 7% grade am i abusing the scoot in doing this?

[@leonardruesga1642]

can you put sealed bearings or do the open ones have to be strictly open

[@49ccscoot]

I've never tried it. I suppose you could, but I think open is the best choice.

[@leonardruesga1642]

90GTVert how about gear oil, 75 90?

[@49ccscoot]

That's what I use. Mobil 1 75W90.

[@leonardruesga1642]

& where do you get all your scooter parts I visited a few local scooter parts shops & they never have anything in stock it's always special order

[@49ccscoot]

I order everything online. eBay, scrappydog, PartsForScooters, scootertuning.ca, etc...

[@user-yj2ew4xc4i]

Чувак красава Все пр полочкам Респект

[@vorkev1]

if you are wored about the bearing breaking then you should not be installing them buy only quality parts

[@aronijabre295]

4:52 What is the seal number?

[@49ccscoot]

17x30x6 If you need bearing/seal/torque info, I have a page of it : 49ccscoot.proboards.com/thread/14211/139qmb-bearings-seals-bushings-torque