GY6 Camshaft Installation Guide

Installing a new performance camshaft is about a 45 minute job, and the engine doesn’t need to be removed.  Only normal garage tools are required.

Before Installation

  • Make sure the chassis and engine is clean around where you’ll be working, so that no debris falls in the open engine.
  • The engine must be cold.

Step 1: Remove these items

  1. Airbox
  2. Carburetor
  3. Black Plastic Fan Shroud
  4. Valve Cover

Step 2: Relieve Cam Chain Tension

Locate the cam chain tensioner on the top of the engine.  Use a cross-point screwdriver to remove the top cap of the tensioner. With the cap removed, you’ll have access to the tension adjustment.


Use a small flat blade screwdriver, and turn the adjuster counter-clockwise until it stops.  Give it a little extra twist to lock the inner tensioner into place.  This will slack the chain, allowing you to work on the camshaft.

Step 3: Cam Tower, Rocker Arms, Camshaft

Remove the four 12mm nuts from the rocker tower and remove the tower as well.  Remove the chain from the gear by tipping the cam gear into the engine cavity and pulling the chain away.

If you drop the chain down into the case, don’t worry.  Use a hooked tool to grab it from inside of the case and bring it back.  Use a flashlight to look down into the case, make sure that the chain is still on its sprocket down inside the engine.


Grab your new camshaft and begin assembling in the reverse order.  Be sure to time the camshaft properly to TDC at this point, or you can run into major valve and piston damage on your first start up.

  1. Starting from the top, install the timing chain over the cam gear.2
  2. Reinstall the cam tower back onto the cylinder studs.  Look for the “EX” imprinted on the tower and install it towards the exhaust valve (downward).
  3. Reinstall the nuts and torque to 22ft/lbs each, progressing to each nut in a cross pattern.

Cam Chain Tensioner

Your chain tensioner should still be locked in its retracted position at this point. Release the tensioner lock.  Don’t try to set the right adjustment, just “bump” the adjuster from its locked position.  Proper tension will be set automatically.

Final Assembly and Inspection.

Reinstall everything in the reverse direction of dis-assembly.

Go Ride!

3 thoughts on “GY6 Camshaft Installation Guide

  1. Avatar louis paradis

    I am trying to ID my grand son gy6 !!
    On the block #244M I
    Ser# 050704708

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    […] Camshaft Installation Guide […]

  3. Avatar rober

    Thank you very much for this website and very easy to read and practical information and high Quality demonstration pictures. I would. Have given a grammy if I could . Please provide assistance. I have done everything. As you instructed on my gomoto nippie 150 cc schooter and it turn when I use my hands but when I want to use the electric starter, it simply don’t even want to turn the engine. I thought it was to tighten to start

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