QMB139 and GY6 Valve Adjustment the Easy Way

The easiest way to adjust your valves on your GY6 or your QMB139 scooter engine is to use the proper tools. Since these two engines have tappet style adjusters for their valves, using tappet adjustment wrenches are the way to go, and if you've ever tried to do this with a pair of pliers or vise-grips, this is so easy it'll seem like a cheat code.
The QMB139 and the GY6 engines use the same clearances for their valves and the procedure to adjust the valves on both engines is the same. If you have any questions, drop a comment here or hit us on the website chat at www.partsforscooters.com.
Featured in this video:
Universal Parts Tappet Adjustment Set: www.partsforscooters.com/202-...
Universal Parts GY6/QMB139 Feeler Guage: www.partsforscooters.com/202-...
Universal Parts GY6 Replacement Tappets: www.partsforscooters.com/165-...
Universal Parts QMB139 Replacement Tappet: www.partsforscooters.com/151-...
QMB139 Non-Emissions Valve Cover Gasket: www.partsforscooters.com/151-...
QMB139 Emissions Style Valve Cover Gasket: www.partsforscooters.com/151-...
GY6 Valve Cover Gasket: www.partsforscooters.com/164-24
A complete listing of our scooter tools: www.partsforscooters.com/All-...

[@jonnupe1645]

Thank you

[@MangScoots]

thanks man, i had a buddy re-do my engine and its clattering like no other, sounds like a constant ticking, obviously ik it should a bit but iv rode this same scoot for 2 years and its never sounded like this, i guess i gotta get my hands on a tappet and guages lol, thanks again man

[@josephchanda65]

Hi i have a question mine is not starting at all but the starter is turning long time not being used were should I start coz I now what to adjust the value am I on the right track

[@sandeepram8429]

Hi, my scooter was making noise, I did the valve clearance and it was solved, but after two days it's like before again. What could be the causes and how could I resolve it?

[@seanmayo206]

What if it was a 1p39qmb but received a rolling wrench 50mm piston complete kit

[@alexcruz9449]

I cant move my flywheel enough to sit on the t it wont let me what should i do

[@coidumalexandrunicolae9458]

Its available for 80cc kit to?

[@lester6340]

Them tool work awesome I order sme

[@Partsforscooters1]

Yes they do!

[@monty81567]

Hello again.I need your help,do you have any GY6 stators that work.The band new motor that I got some time ago has no power on the spark side,it has power on the other side.Did check it with an omh meter,watch a KZbin to make sure I did it right. Question-can I swap out the 8 pin stator and put in a 12 pin stator for more even flow of electricity to the lights.

[@Partsforscooters1]

On a 50cc motor, there isn't really a high power option

[@monty81567]

Hi,I found two parts over at your website,Right Engine Crankcase Cover but there are two sets of #'s.One is for 47 tooth gear and the other is for 33 tooth gear.Too fix the old motor,Let me guess- have to take the cover off to find out.

[@Partsforscooters1]

You sure do

[@monty81567]

@@Partsforscooters1 Thank you.

[@jarodhuber2687]

Hello! So I have a question. My scooter has poor idling issues whenever I come to a stop. Sometimes it just wants to die. I thought maybe the valves needed adjusting and did that to correct spec. However it’s still not idling right and almost dying at stops. What’s the issue? Is it carb related? Thanks.

[@baileylakey7390]

Likely needs a carb clean, sounds like idle jet may be blocked

[@seanmckay3392]

Maybe your clutch is shot i had that happen one of my springs broke and it wanted to drive all the time

[@monty81567]

Hello.When I started modding my Racer 50(2019),I made mistakes on the motor,to many lights. Now it's back in the shop & got rid of the extra addons.Ordered new parts,new motor,clean the gas tank out. While going thru my collection of old parts i found a press on final drive gear with 13 teeth.the standard drive gear is 15/52.That drive gear(13) would make it slower? Going to bump it up to a 80cc.The frame weight is 187 pounds & mine is 190lbs or should I have my guy bump to 100cc.

[@Partsforscooters1]

How fast are you looking to go? Also, the 50cc 4t bikes can't go up to a true 100cc so what kit would you be looking at? As far as the gear, do you only have the single gear or do you have the complete upgear set? A single gear won't do you any good as the gearsets are cut to work together. A single gear might not mesh well when installed.

[@monty81567]

@@Partsforscooters1 Saw one of your older videos about final drive gears.I want to set it up so I can maintain the speed around town,where I live the speed is 35 to 45 mph. Even if I left it at 50cc & change out the gears,press out & add the 17 teeth and the 49 teeth that came with it. Would that give me another 5mph?

[@Partsforscooters1]

@@monty81567 No. The stock engine isn’t powerful enough to push taller gearing. To get a reliable 45 mph you’ll need to install a pretty stout big bore kit at least. Take a look at the Naraku 52.4mm kit. After you get the BBK running, you can start to tune your variator and weights to it, and after you get that done, if you still need more speed you would start looking at gears. They’re usually the last thing you look at. www.partsforscooters.com/137-4-Naraku-Cylinder-Kit

[@monty81567]

@@Partsforscooters1 Thank you for your help,I wish I had found & talk to you back in 2019 before I did any mod's to the motor. Would've just did the upgrade and left it alone. This summer my brother & I got are motorcycle Lic,pass the ridding & the written test. Been rebuilding the back half of the Ninja 250,ordering parts that were missing,plastic pcs,hardware,new blinkers & mounts all were broken. 1st owner treated it like a stunt bike,2nd owner no better,everything was dry out. Thanks for your help.I let you know how everything went,when upgrade is done.

[@Partsforscooters1]

@@monty81567 Too bad! We’ve been doing this for 20 years now. Sounds great, and if you need any more help, just go to www.PartsForScooters.com and use the live website chat. One of us will be happy to help.

[@jdub_bkv6598]

After i set valve lash my gy6 has a loud tapping noise. Now what do i do? Any help would be appreciated

[@jdub_bkv6598]

Note: I did .004 for both int and exh after watching a different video so I will probably set exh to .005

[@Partsforscooters1]

@@jdub_bkv6598 Set the exhaust to.005, but these engines typically make a tapping noise when they're running correctly. If it's VERY loud, you have some other valve issue that needs to be addressed.

[@robbygaume600]

The thing I like best about your video is that you give a close-up view of how to align the holes on the cam gear to get the motor a TDC.

[@yardcandy]

Could we have the cover bolts torque setting please ?

[@adivarso8175]

just number each one and mark them before undoing them, then re tighten to the marks you made.

[@yardcandy]

@@adivarso8175 good tricl, but it's too late for that, would you have the number? (yes I can also compare the bolt size with a chart and get it but still)

[@Broken_AK47]

there is something wrong. every manual state MM and from 0.04 to 0.05. all of them. even the service manual for my 2020 scootterre bistro 50 from the dealership says 0.04-0.05MM. and your tool is like 0.10mm or 0.004 inch. both terribly wrong. are all manual in the world wrong ( damn chinese stuff ) ? or the marking on the tool is wrong ? i need to know. i have a quality ( OEM TOOLS 44025 ) feeler gauge but it starts at 0.004 and is thinner than a paper sheet. its more like kitchen aluminium foil. been told its not the right one for 139qmb valve gap. thanks

[@Partsforscooters1]

.004 and .005 are correct. .04 and .05 are WAY too large.

[@ericmcmillin9266]

Please for the love of God anybody that does a valve adjustment...torque the tappet nuts to spec!! Do NOT hand tighten them. Use a torque wrench!! They have a tendency to back off the thread.

[@Partsforscooters1]

Actually yes, I should have added that: 7ft lbs IIRC

[@blacklabeleadslinger]

That's never all there is to it...

[@Partsforscooters1]

I mean, that's pretty much all there is to it.

[@straggler666]

That's a socket not a wrench

[@Partsforscooters1]

Thank you for your pedantry.