How To Adjust Your 2-Stroke Clutch – 48cc 50cc 66cc 80cc -Motorized Bicycle


Sometimes during the manufacturing, the clutch
pads on some Grubee Skyhawks are overly tightened, so when you try to disengage the motor the clutch
cover does not separate from the clutch pads. This issue is found in some Grubee Skyhawks
and in this video I’m going to show you how to resolve it. Simple tools you will need:
Spark Plug removal tool, flat head screw driver, a phillips, and a hammer. Naturally, there
will be some resistance on the clutch arm. My advice is to use your spark plug removal
tool as leverage to push the clutch arm down easily. To check to see if you need to adjust
your clutch, Push the clutch arm down towards the engine and attempt to spin the engine
sprocket with your finger. If you are unable to move the engine sprocket freely, you will
have to adjust your clutch. First step, remove the gear case cover from the engine. You should see two gears, one large and one small. On the large gear, there is a wing nut in the middle of it and there is a Phillips screw holding it in place. Unscrew the phillips. Remove the wing nut by
turning it counter-clockwise using a chisel and hammer. Or a screwdriver and a hammer.
Once you get it about a half to one turn, you can pull the clutch arm in and hold the
clutch cover down to remove the wing nut easier and faster. Once the wing nut is removed,
remove the clutch cover. Then, remove this spring. Now three pegs are now exposed. Rotate
the pegs to make sure they spin freely. Some resistance is normal. If you are unable to
move the pegs freely with your hands, gently assist it by tapping it lightly with a hammer. Once you are able to spin it freely, reinstall the spring and then the clutch cover. Reinstall the clutch wing nut hand tight. The way the clutch works is that the clutch arm pushes the clutch cover away from the clutch pads, freeing the drive chain so you are able to
pedal your bike. Which is the disengaged position. When the clutch arm is not pulled in, the
clutch touches the clutch pads which then engages it. You want to adjust the wing nut
so the clutch cover moves an 1/8th of an inch when you disengage the motor properly. And there
you go. If the displacement is more than 18th inch, then your clutch will slip when attempting
to start the engine. If it is less than 1/8th inch, it will be too tight to disengage. Make
sure you adjust it just right. I’m going to go ahead and place the screw back on. Then when that’s all done, replace the gear case cover.

100 comments

  • THANKYOU

  • Noel-The She-Male

    great vid. thanks. how did you remove the engine mount studs?

  • shredderjoachim

    Hey man here is my problem. I have tried putting the cover that goes on to the sprocket on the side of the clutch that you were showing in the very beginning of the video but the pin is blocking me from putting the cover back on. I have tried taking the clutch cover off and the plate as well and fiddling with some of the settings. I cant get the stupid cover back on that you took off because the pin is seated way to far out of the housing. I have checked for dirt and grime.. help please!!

  • That's the first time I've heard of that problem. If it doesn't effect your flower nut negatively, you may want to file down the clutch pin. Please do so at your own discretion though, as we are not reliable for this advice. PLEASE NOTE: do so ONLY if it doesn't affect the flower nut negatively, as in, it causes the flower nut to sit and screw back on the clutch pin improperly.

  • Remeber too also check your gears for any foreign objects before puting the cover back on. Even the tinniest shard of metal with really screw up the internals of a and engine.

  • hi there, did you get your fixed. Im having the same problem. Went into gear initially, now it wont go into gear at all. Stays in neutral. Did you figure out what it was. Thanks

  • Hello, I was wondering if you might be able to make a video on the new centrifugal clutch flying horse engine kit because I am interested in buying one in the future and I'm sure others are too. It would be a great help if you did so. Thanks

  • This is trouble shooting not adjustment, but cool video…

  • What if clutch is not un ingadgin

  • my clutch gear is rubbing on the bottom of the motor case WTF do i do?? i tried this out of spite but no luck obviously is the gear grinding along the bottom Plz help?!

  • let says if  my motor is off  and i ride my bike for 4 miles my cluch will get bad

  • Ok i just set mine up and when i try to pedal that engine tries to turn over and wont let me pedal will doing this help

  • My clutch is stuck stuck stuck. Those three prongs won't spin no matter how long I bang on them. I'm afraid I'm going to break them.

  • the clutch handle is stickey 

  • Thanks that was really helpfull I was looking everywear for videos on how to dismantle clutch and u answered my question

  • Hi Bike Berry, I find your vids very helpful. I have built 5 of these Grubee Skyhawk kits now, and sell them. The last 48 cc I did has a rattling noise in the clutch area. Now I have heard this is "normal" sometimes the pressure plate is out of round or something like that? I haven't opened it up yet, but do you have any suggestions on what that rattling might be? the nut loose maby? The engine and clutch work except the clutch will not engage until the clutch lever is almost ALL the way out. On my 66cc it is not like that. I will try and adjust it this weekend and see if anything is loose in there, but your opinion would be greatly appretiated! 

  • I have a 66 cc skyhawk and When I hold the clutch in, my bike doesn't move how can I fix it?

  • How do you take off the sprocket from the clutch? The videos on YouTube only show you how to adjust it

  • How do you take off the gear ***

  • J Danny Casillas

    if I am replacing my square like clutch pads with new ones, which direction do the new clutch pads go in? One side of my pads look checkered and the other side is black……and what if the holes seem alittle too small for the actual pads to fit in.? Is this common? and what do you suggest to make the pads small enough to fit?

  • Should you do this when u first buy the motor ?

  • can u do this with the engine mounted and built

  • No one has made a video on a complete rebuild of a Grubee clutch yet.  There is an issue with the clutch on these engines.  The adjust nut(not the fine adjust nut) on the clutch shaft screws tighter and tighter against the clutch spring until it completely compresses the spring rendering the entire clutch(and engine) useless.  Very poor design.  2 of the 3 engines I own have done this.  Again, I'm talking about the part of the clutch inside the engine, not the fine adjust nut under the clutch cover.  I have to figure out a way to stop the adjust nut from tightening itself on the threaded clutch shaft.

  • RockLobster2402

    yeah got everything installed- and first time trying to start the bike the chain breaks at the master link, so I bought a new Master link and reinstalled the chain. When I tried to tried and engage the engine to start the bike it just completely locked up.
    Called bikeberry the guy was real nice he said to look at this video
    my question is the engine is installed already and chain is on so do I have to uninstall the chain to do this? I guess thats a really stupid question since I just said it is locked up how would I get the chain out?

  • I just got my bicycle engine kit to run and I was running it at full speed for about 2 min. When I was doing a tight turn  I slowed down and the engine turned off. I held the clutch to turn it back on but in the process it became to stiff to turn. The engine was hot and I was holding the clutch but it still would not spin. Would this fix  my problem?

  • I just finished assembling my bike but when i tried to pedal it, it was very difficult like the clutch was engaged even when I held the clutch lever. So then I adjusted the clutch like in the video and now it spins freely all the time and won't engage. 
    any suggestions @BikeBerrycom ?

  • Miguel Hernandez

    This was exactly what I needed! Thanks!!

  • The wire for the throttle cable is stripping away trying to assemble it its the wire that you put the springs on that turns the thing on top of wear the chain sits its to turn twords the engine but the silver wiring that you screw down is coming on ravled and the springs are being difficult to put back on

  • conker balderas

    Hi could you tell me how to tighten the clutch because i can pedal freely while clutch is on or off

  • this is a bit off topic but, does clutch starting the engine harm it?

  • Tnks man! Right to the point.

  • Tnks man! Right to the point.

  • my clucth wont engage it is very loose every time i move the bike the pitins move very easyley so it wont turn over properly any advice

  • if you`re confused about fuel to oil ratio, you can do what I did , go to you`re local Honda shop and buy a measuring cup for 2 cycle engine oil , you can buy oil there too .

  • My clutch is very tight and hard to engage and can't be engaged by the wire, is this going to fix my problem?

  • I am completely unable to unscrew the philips screw that locks the flower nut. I've tried a couple days now trying to unscrew it and now its stripped. Any advice?

  • i haven't started the motor yet but i noticed that assembling the throttle to the carburetor the cable was extremely tight. it doesn't seem to fit right… is this normal? also i did the test for the spark plug but never saw fire, how do i know its not the spark plug but the wire box?? HELP!!  

  • excelente 

  • unresolved problem… the system i received is totally seized… unable to turn the engine sprocket freely or at all. and loosing the clutch cover does nothing to resolve the matter…

  • can't get my bike to start, the fuel valve is open, the choke is up, the white lever on the carb where the fuel enters is up at 90 degrees, the idle adjust screw is about halfway,…anyone have any ideas?

  • Can't get mine to start. When I try to start it, I will pedal then let go of the clutch, and when I let go the bike keeps rolling for another meter or two, and there's is no sound of the bike trying to start, any ideas?

  • Can you guys make a tutorial on how to replace an engine head and piston to a new one.

  • Pittsburgh Steelers

    Chinese engine are so slow they need to make them faster

  • Theodora Czarnecki

    I'm a 72 yr. old female riding my Dewey motorized bike for about three days and all of a sudden the chain seems to lock up and breaks.  Do I just fix it with a master link  and try to start it or do I have to take the chain off and how do I take it off?  Do I have to take the cover off of the part where the chain goes through?  Does the locking up have to do with the clutch, as shown in this video?

  • hi its me again thx for solving problem with wires but now im struggling to start up engine and i dont know what cause this I have spark now and when im trying to start up i release clutch engine is trying to get on but quick time its dying . before i opened clutch and i had to adjust this cover cuz these sprockets werent moving at all and i couldnt get spark now its all sorted but maybe i put something wrong thats why its struggling to get the engine on now ?

  • Nice video guys! Very clear instructions!

  • When i pull in the clutch and release it it is stuck and will not release any help?

  • Hi, got a used Bikeberry, replaced electrical, and finally got it to start. Was zipping along nicely when it appeared to seize up. I can barely run the wheel to move the chain. Any thoughts on what to do?

  • Question?I'm putting a 48 back on after getting a faulty engine from zb upon re attaching the chain I noticed the bike moves freely with no clutch cable(always trying to start mode)any tips or tricks for that issue.

  • what happens if i spin that small gear? i used that to spin my chain on when i installed the kit and my bike worked at first but.now wont accelerate

  • should the gears turn when you turn the three bolt cause my engine won't start and it's new

  • Zoological Militia

    Man if your going to do videos boost your volume.

  • how do I idle the motor?

    also the clutch doesn't work… it says as if the clutch is squeezed when it's definitely not

  • very clear,,,thanks!

  • simply super video……..thanks
    BILL DRAKE

  • i just got my kit all together got it running good but the clutch squeaks so loud when accelerating does anyone know why?

  • great vid. now I can fix my problem! thanks

  • thanx for this video…i tried tightening the cable for an hour and still it wouldnt disengage. thanx to you ik up and running

  • mine don't have a spring is that normal?

  • THank You.

  • IntoxicatedCockroach

    hey man sorry to bother you, my bike used to lock the back tire when the metal thing on the clutch was up and it will move freely when down and now it moves freely both ways like its not working right and it wont turn on when i try?

  • Do not use a hammer or chisel use a 15/16 socket on the clutch flower nut!!!!!!!!!!!!!! Works so much better and you do not beat up your clutch flower nut!

  • what of you can't move the three pegs at all?

  • thanks your video helped they all do!

  • Mine had the spring but i removed it because it would pop out the screw and make it fall/scrape the clutch cover. Is there any problem? I know new engines don't have it, and mine seems to run just fine without the spring,even a little better than before i would say..

  • I just replaced the ball bearing behind the clutch pin but now the pin sticks out way too far. Is it an 8mm ball bearing that's supposed to go in?

  • William Sevier

    How long does a clutch usually last, and is it serviceable?

  • this was so very helpful i thank you for making this video.

  • Thank you. This was sooooo helpful.

  • What do I do if the 3 pegs don't spin (even with hammer clockwise)

  • great, informative video.. thank you!

  • I just put on my brand new motor and the clutch gear isn't turning with ease with the chain on

  • what am I doing wrong

  • Personally, I would use a pair of needle-nose pliers to remove that nut, not a hammer and screwdriver. There is something odd about my clutch setup right now not sure if the cable needs to be tightened or if that nut that you took off with the hammer needs to be loosened.
    I had no friction at all thought my clutch pads were toast but when I got into it I realised that the pads are fine and only needed to be tightened a bit but I had to turn that nut to a spot where I could put the screw in and now I think it may be too tight either that or the cable has slipped, any input would be well-received thanks.
    Also, can anyone tell me how you can test a boost bottle to see if it is doing anything?

  • my pegs do not release i used the hammer, what can i do

  • Butter My Biscuits Mabey Baby

    so… the screw that holds the wingnut. I found it in between the gears all chewed up.. wtf. I was wondering why it was making weird noises. should I ask for a replacement motor cus its kinda fucked

  • it's easy to see that you're an untrained amateur but you know what I congratulations you have made a video that's a lot better than some of the ones that I've seen. outstanding work I believe you should get an education as far as a technical field and I think you will do very well with that sir. but if you can become a doctor, lawyer, or an Indian chief. or whatever your heart may desires congradulations too you and good luck

  • Yamaha.Rider 2001

    Don't buy this shit, I did, I spend over 400 dollars on mine, and you wanna know what happened? The fuckin 2 front motor mounts sheared clean off when I bumped started it, totally unreliable and don't waste your time and money, I tried to tap and die it out but the motor casings cracked, so they want you to spend extra money to prevent this shit, and I did, but it didn't work. Thanks a lot you fuckin morons. Wasting my god damn time and money

  • Mines been too tight for years! Finally figured it out thanks to you! Thumbs up

  • how to fix the clutch arm from moving out

  • Thanks bikeberry! The pseudo manual that comes with the kit is so utterly incomplete and confused, you've been a great help already! ^_^

  • Bravo, thanks!

  • Thanks

  • I have a problem with my clutch, every time i adjust and put it back together i can walk it about 10 paces and it locks up again. I've tried adjusting it tight and loose doesn't make a difference. Any advise would be appreciated.

  • thx very much,nice explication fast,simple!!!

  • Thank you for the video. worked very well for my situation.

  • Thanks bro just sorting my clutch now an i needed your vid to sort it

  • This video saved my bike. I ordered a pull start because it wasn't starting ever, looks like I don't need it now.

  • Vahagn melikyan

    Do you have videos of your different engine products, in size epa and so on

  • DirpyEndermen 01

    What type of bolts are those were the chain and is i lost my bolts and need to buy nww ones

  • Thank you.I can't keep the dang Nut from the Clutch-shaft tight.I put the inside-star washer in,after doing the first part of the Video,as I HAD to so I Could get 'Triple=tree'loose.>All went well for the first start,and 1/2 block.All tightened and it didn't want to stop.I Had to get to Apptmt.After Appt,the clutch kept spinning nut loose behind plate."Help-Plz'

  • I have a different problem. The rod that sits at the center of the drive sprocket is permanently depressed, leaving the engine always engaged. It can come out like it should but does not spring out from the engine

  • Emilio Rueda Piper

    thx for the helpful video !!

  • Wow very old video the Skyhawk is the best engine ever it's funny that they were talking crap about it because the new engines are a joke every single new engine sucks compared to the Skyhawk 66cc I had a Skyhawk one time that I ran without an air filter for a 7000 miles and I never even adjusted the clutch one time yes that was an exception but that did happen and it was like a 2012 Skyhawk motor go figure

  • Never adjust the clutch before mounting and running the engine because when you run the engine a couple miles the clutch is going to change because it wears in

  • beat with hammer! got it!

  • If the motor is engaging with everything else seemingly in order I should loosen the flower nut? Correct?

  • Santiago Motorbike’s

    Love that bike berry Channel have a ? About a motor I got from use The motor and greet for about two weeks now turning The motoring great for about two weeks and now The motor is not coming on all the way please email me and I can send you a video
    [email protected]

  • omg you are bad mechanic you ruining clutch after dispensation
    wait for new video clutch ruined you need full strenght of spring for better performance

  • Wow thats china copy for russian d4

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