GY6/139QMB 50cc 4-stroke [Chinese scooter] COMPLETE transmission disassemble/reassemble
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- เผยแพร่เมื่อ 24 ก.ค. 2024
- In this video we completely disassemble and reassemble a 139QMB chinese scooter engine's transmission. The main components are the variator, the drive belt and the clutch. A MUST-SEE video if you want to do any kind of performance tuning to your 50cc scooter.
0:00 - Intro
0:20 - Tools Needed
0:32 - Removing the CVT Cover
0:58 - Transmission overview
1:07 - Removing the crankshaft nut + variator fan
2:15 - Removing the clutch nut
3:06 - Removing the drive belt
3:14 - Removing the rear pully (clutch)
3:18 - Removing the variator
3:27 - Variator inspection
4:39 - Clutch overview
5:03 - Flat clutch nut removal
6:01 - Clutch disassembly
6:53 - Clutch reassembly
7:47 - Belt inspection
8:09 - Variator reinstallation
8:14 - Reinstalling the drive belt
8:52 - Reinstalling the crankshaft nut + variator fan
9:14 - Reinstalling the clutch nut
9:20 - Torquing down bolts with a torque wrench
12:00 - Reinstalling the CVT Cover - บันเทิง
Thank you.
Thanks for doing this bud! It’s really helped me out today
love you
Dude what if i tightened against the belt on the variator like you said not to? I think i maybe did that. Ever since i put a new belt on my scooter it just seems to not have the top speed like it used to have
The spring usually works best when you use the right springs on the clutch shoes so yellow 1500 contra springs and yellow 1500 rpm clutch springs.. also if you lightly sand over the clutch shoes jus enough to get rid of the glaze( same thing with inside of clutch bell) the clutch should grab more easily.. also if your spacing is off in the variator side this could cause your belt to not ride all the way down in the front or if it is to loose it could also cause slipping. But those are all key to tuning your CVT for performance
What size is the clutch big nut in mm please?
39mm, according to some online conversion tables
I think you put the spring in upside down.
I noticed that, eventually I put a different spring in and put it right side up, but I don't think it makes much difference
Please please please please please get and use impact sockets for your impact wrench. It's extremely dangerous to use regular sockets with one. They will shatter.
I have impact sockets for the heavier-duty stuff. In my years of experience, I have never seen a handheld 16v impact gun be able to shatter a socket.
I suppose if you were using a corded wall impact gun that could put out way more force, you'd eventually shatter the socket lol
@@GTAIVisbest Better safe than sorry. Especially if you're using cheap sockets. I've seen them shatter and throw projectiles everywhere. Not sure if they were quality sockets or cheap ones though. Anyways be safe please.
i tried to take my clutch off for the first time and the nut holding it to the moped is tiiiight as fuck i don't know if it came like that from factory or if previous owner got in there and just fucking cranked it down and loctited it
Nah it's because over time those nuts get really really fucking tight, any nut will be like that. Try disassembling a moped that's been used daily and never disassembled for 10 years every nut will be "cold-welded" or something like that. You're going to need a corded impact gun that can really dislodge it OR apply localized heat if you're able to
@@GTAIVisbest haha bro love ur name and yeah this moped is 14 years old with i think 3000 kilometres on it so not too many km and no corrosion on the nut ive tried hitting it with propane torch and battery impact driver i think i need penetrating oil heat it up super hot and hit it with a rattle gun i think
@@GTAIVisbest i hit it with a propane torch but the clutch absorbs the heat fast so i don't know if i can get it anywhere near red hot
thanks for the reply though man 👍
You'll want a CORDED rattle gun and then hold the clutch in place and make sure you're pushing up against the nut (otherwise you'll damage the nut with all the force) and hit the rattle gun with as much power as you can, and boom! It should come off@@tbounds4812
So your bendix is not noisy after you do that hahaha just kidding
looool sometimes I hear the bendix "rattle" a bit when I turn but somehow it always works perfectly. I think it's always been like that :D
So....instead of just using your Impact..... you use a "torque wrench" to loosen a nut....... okay. Not a good idea...but do you. Hopefully you never use that tq wrench to tq anything haha, good video regardless.
Haha yeah, basically the torque wrench I used was specifically a "throwaway" torque wrench that acts exactly like a large breaker bar would. I use it only for loosening, I have a dedicated torque wrench for tightening :)