The Complete and Definitive Tutorial Guide for the 50cc Gy6 139QMB Big Bore Kit Install

I try to cover every part of a BBK cylinder swap and information on cam swap. I believe in DIY and you will always do a better job than a shop if you do it yourself. I am installing a Naraku 100.52 kit on a IceBear Maddog 49cc Scooter.

[ryanpage]

I paid someone to do my bbk. Then I found out about all these bbk not really being true upgrades. Met a guy at church whose son had a 50cc that he planned to upgrade. He bought the bbk and then his son sold the scooter! He just gave me the kit so I have now torn the whole scooter apart and have been trying to piece it back together over the last two years (my first attempt It started up all fine and then died on me after 5 mins of riding it. Bought a compression tester and ended up with not enough compression). My gasket set just came in the mail, this is the FIRST in depth video that I’ve come across with full in depth information. Now I’m second guessing my ring placement on the piston head and I’m glad I didn’t get further than getting the piston in the cylinder. God bless you for taking the time to make such an in depth video!

[MalleusSemperVictor]

Valve lash is about 3 business cards stacked on top of each other for "field" adjustments.

[Donbscooters]

Love ur videos man u do explain things to a t. And that I like . And straight to the point too don't do this or do that . Tell it like it is keep up the good work man . A long time sub here until the next one

[Romin.]

Very informative video.
I'll be watching it again as a guide.
Thanks.
:)

[jacken]

I'm glad you're building 139qmb's and taking the time. The Naraku and Ssp-g kits all day! Me and some of my buddies over at S.A. mostly official are into building these lil engines up to show what they can do. This is my fourth build

My 139qmb- #1
Uni filter
20mm round slide carb
20mm pit bike intake manifold
Ssp-g 52mm 23.5/20.1 head
Ssp-g titanium valve retainers
Ncy cam
Ssp-g 52mm flat top piston and jug
Taida 44mm stroker crankshaft - 22 tooth sprocket
Ncy ignition
Ssp-g full exhaust system
All emissions, vacuum lines and fuel pump have been deleted - gravity feed fuel line setup

Ssp-g 89mm variator - longer ramps!
Ssp-g drive face
Gates power link belt
Ncy clutch bell
Ncy clutch
Ncy secondary sheve
1, 000 rpm clutch springs
Stock contra
Ncy contra ball bearing kit
Ncy 18/46 secondary gears - 2.55

139qmb #2
Foam filter
20mm round slide carb
Gy6 125cc 22mm intake manifold vs150cc 24mm
Ssp-g 23/20 head pocket port, open exhaust to 18.8, mild valve deshroud and milled.
Scooterarmy's S.A88 52mm dome top piston
Stock crank
Amazon exhaust
No emissions b.s.
92mm TWH variator
Ssp-g drive face
Stock modded clutch and bell
1, 000 rpm clutch and contra springs
17/49 secondary gears - 2.88

[Valentine]

Ayeeee yo
I watched this so many times before i did it myself lol

First start took a awhile had me worried af but it was battery🤷🏻

Working on it in this florida heat but it was worth it for my "100" cc

Godbless you!

[DustySteel]

I literally just installed my big bore kit and definitely would’ve benefited from watching this video first lol.

[blizzyland]

great video! so much good information, i dont even own one of these but was still worth the watch

[Pipeargill]

Awesome, wish i had this video when I first got into this. Great info, not annoying. I'd love labeled chapters on something this long though.

[jhammer]

Excellent video! Thank you! I have a stock 150cc. Big Bore is next. Out of the crate, I got just about 52mph. I did a Nibbi carb upgrade with an exhaust upgrade. A little bit of carb tuning, I'm at 58 to 59 mph. No CV tuning. Running bone stock. Hoping that with a big bore kit, and some CV tuning, I'll get 65 mph our of it. Thanks again for another great video!

[Valentine]

Glixal strong over here rn lol
Thank you!!! For this tutorial thank you thank you

[dkewlguy]

So what is all the lubrication I need? I have Lucas oil assembly lube and the scooter oil and gear oil. Where do I put what? I have my head and cylinder right in front of me and I’ve put the piston back on. To put the boss back in the piston I used assembly line. And only on the boss.

[wesmadebuilds]

I will be interested to see your thoughts on the Naraku parts. I have had nothing but bad luck with their stuff. Probably just picking the crappier stuff they make, but who knows.

[username-mkgf]

I heard about gy6s for years, the robust, standardized true engine for scooters and small bikes, but I didn't know it was a swing arm. I want to mount it on a minibike.

[VmtSquad]

Great video man! Thanks! Can I ask you from which model you took front end cover? Is this from a ruckus?

[jayb]

Amazing video! I just almost finished putting a Glixal 72cc bbk on my maddog thanks to your video! I just need to pick up a torque wrench and set my valves and I'll be good.

The kit came with 2 red little rubber things I have no clue what they are for but it all went great so far.

Do you have to put back the plastic coverings over the engine? Everything is easier to access with the plastics off so I was wondering if it would mess anything up if I left it off? I would just put the one over the fan and variator.

I'm waiting for the variator removal tool to arrive so I can swap that one out with a Glixal 89mm variator. Not sure if this will make a change. I bought it before I watched your variator video and saw the stock maddog is 86mm. Oh well.

[Hamistar]

Dose anyone have experience with the Chinese kits and performance heads

[TaoTaoTye]

banger of a video! i have a question if you dont mind, my qmb 139 is running loud as heck, i just had it rebuilt and its making alot of ticking and or clicking and seems to be running kinda weird, im 99% sure its my valves but what do you think

[dkewlguy]

What kind of corrosion compound do you use?

[xaviero]

What jets are you running with this kit now?