How to Adjust Valves on a Motocross Bike

On four strokes engines motocross bike, the engine is designed for sports use, so it’s necessary to regularly check valves adjustment. This is a manipulation which is not so difficult but requires attention and patience.

1) Dismount the saddle and the plastic. Remove fuel tank and each aesthetic part which could interfere with manipulation around breech.

2) Remove the cylinder head cover. You can see both camshafts with distribution chain.

3) Remove ignition cover. This will be useful later to rotate the camshafts and thus find the quick link in the distribution chain.

4) Check the valve adjustment. For this, place the piston at TDC. Take the workshop manual and look for the adjustment. Then take shim and compare with the data constructor. You can then deduct the value of blocks up.

5) Make a mark on each sprocket and chain. Attach the chain by string or wire, then remove the chain link and shift the chain to have free access to camshafts. (You can also just relax the chain on some models.)

6) Unscrew the screws holding the camshafts and remove them quietly.

7) Take a magnet that’s rather thin, and remove the pads with it.

8) Change the pads with other ones which have the correct thickness.

9) In the same manner that you removed the pellets, use the magnet to put them back into place.

10) Put back the camshaft. After, it returns the chain in place, making sure that the brand is facing. Stretch the chain.

11) Check if the valve clearance is good. If not, check the valve adjustment again.

12) Put back each peripheral, ignition cover and head cylinder cover. After, get back fuel tank and plastics.

For Dirt Bike maintenance parts and more, shop with our sponsor