How To: Adjusting Your 2-Stroke 48cc, 66cc, 80cc Clutch
2-Stroke bicycle engine kits run on a "dry clutch," or a clutch that uses a system of gears and bearings to engage and disengage the engine. What makes these types of engines better than pull start engines is that you have more control over when you start and stop your engine, as pull starts tend to give out pretty easily after heavy use. The problem, though, is that dry clutches, like all clutches, can begin to slip over time. Luckily, these clutches are pretty easy to adjust, and all you need are a few simple tools:clutch
  • A flat head screwdriver
  • A Philips screwdriver
  • A hammer
  • (optional) A spark plug removal tool
Start by taking off the gear case cover on the clutch side of your 2-stroke engine, exposing the clutch plate and clutch wheel nut. Use your Philips screwdriver to take out the locking screw in the center of the clutch plate. The clutch wheel nut should be able to freely twist off, but if it's stuck you can always loosen it. clutch2To loosen that nut take the flat head screwdriver and place it in one of the grooves of the nut. Going counter-clockwise, press the screwdriver against the nut and tap it with the hammer. Don't strike the hammer- tap it to loosen the nut. Once loosened, take off the nut and remove the clutch plate to expose the clutch bevel wheel and clutch pads. clutch3Once these are exposed locate the three pegs in the center of the bevel wheel. Try to move the pegs. If you can't move them freely, take your hammer and tap one of the pegs clockwise, then counter-clockwise to loosen them. Remember: tap, don't slam the pegs or you'll damage the bevel wheel. Once they're loose enough to turn, assemble the clutch plate back on to the bevel wheel. clutch4Lastly, push the clutch arm in toward the motor and watch the clutch plate pop up from the engine. It should only pop out slightly, so if the plate is too far out press the plate down so that it's a few mm's away from the bevel wheel. Lock in the clutch wheel nut and locking screw, release the clutch arm, and you're ready to ride! (Note: older bike motors have a spring under the clutch plate that helps engage and disengage the motor. If your engine has this, simply remove and reinstall the spring around the locking nut of the bevel wheel assembly.) clutch5You'll want to be sure the clutch plate is making contact with the clutch pads, but not too much contact. If your clutch is too tight (i.e. if the clutch plate squeezes down on the pads and the clutch arm is locked going in toward the motor) you won't be able to move the bike's rear wheel, locking the bike and engine altogether. If your clutch is too loose (i.e. the plate doesn't make contact with your pads) the motor won't start. Once all of that's set just put the case cover back on. Still not too sure how that clutch of yours works? Check out our video on adjusting your bike engine's clutch here.

24 comments

BikeBerry

“Hey Steven,

In regards to this issue, you would want to make sure the throttle is installed correctly. There may be an issue where you either have too much play or not enough play. For the best results, we would advise reinstalling the throttle. If this does not work, please contact us at 1-800-317-0479 and we would love to further assist you."

Leon

I had the issue with the clutch not engaging and this helped fix this

BikeBerry

“Hey Jaime,

We can help you out here or you can email our support at support@BikeBerry we are here to help!"

Jesse

THANKS.

BikeBerry

“Hey Josh!

That is correct worn our or damaged pads can cause the clutch not to rotate properly and give trouble to the start of the engine. You always to make sure its checked."

Steven Morris

I have a 2 stroke bicycle and my clutch handle won’t engage and disengage almost as if it would have to be do e manually like it’s not spring loaded no more what’s my problems

BikeBerry

“Hey,

Great Question! Grease is not necessary however, you can still apply it and would help the engine. We do advise not putting so much so it may not cause the clutch to slip as properly."

BikeBerry

“Hello Christopher,

If you are still facing this issue then you would need to perform the clutch adjustment again. Be sure to go through each step carefully to insure that the clutch is being adjusted properly."

Thomas

O got a new motor 50cc for my beach cruiser and when I was riding it . It sounded like the clutch is making a wining sound but when the clutch is engaged it doesnt js this normal during break in thanks for the help on the phone buddy

Trick Kid

I did not know that this was even a thing until i called in and the lady told me to have my clutch adjusted and directed me to the video. This worked and it was easy as hell.

Jaime

I had a question. Can I email you or on here is fine?? It’s about my clutch for my 80cc motor

jeffrey buchalco

Thankyou bikeberry for providing a concise information on bicycle clutch adjustment with images for those of us lacking u-tube access! Very handy (redjeff53@gmail.com)

Josh

So worn out pads will cause the bike not to start?

Tom

This blog describes exactly what is happening and I found it very helpful

pooja

“Good way of diffrenciation,clear and precise
Thanks a`lot !”

vinny

Great stuff !

Tony

I have a flying horse 66/80 cc motor kit everything went on pretty smooth thanks to all of bikeberry’s helpful videos.

Jaya

useful post ..short and clear information.

Taxidude

This is not a, this is more of a question I need to know on a two stroke the ball bearing and the Bucking in the dry clutch system please help if you can

Aaron

Hello my name is Aaron.i have a 80 cc motorized bike.i had it started and running. So I took It for a drive and everything was good

mark

I just built one Friday and this is the coolest thing next to cars that has happened.

Christopher

I just installed an2 stroke 80cc motor on my cruiser .I can’t seem to keep it running when I come to a stop.what’s my issue?

BikeBerry

“You’ll want to make sure that when knocking the pegs loose (if you have to loosen them), you tap one of the pegs to help the pegs rotate 360 degrees to the left. If that doesn’t work, try tapping on one of the pegs to move the pegs 360 degrees to the right.

If you need to clean your clutch of debris, we suggest using Carburetor Cleaner. ""Carb"" cleaner helps erode dirt and sludge in the carburetor, but is also handy when you need to clean other parts of your engine like the clutch."

Dhani

“It about The three pegs you said. I dont understand actually with thus setting.
If turn it clockwise mean?
If turn it counter clockwise mean?

And one more question that would help me. What should i use to clean the clutch? There was much dust and debris because clutch friction. Worry to use any material to clean it,i dont want the clutch getting slip because i use wrong cleaner.Thank you. Your answer so helpful for me"

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