Part 15 Removal of Cylinder Heads ...

Introduction ...

This page contains photos of the process of removing the cylinder heads from a ROTAX 912ULS engine (built August 2006



ROTAX 912ULS Cylinder head Removal

Image 1

Start by removing the rocker cover. There is a single allen head bolt retaining the cover ...

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ROTAX 912ULS Cylinder head Removal

Image 2

Here is the rocker cover and it's retaining bolt on the bench. Note the small o-ring that provides oil sealing around the retaining bolt hole. Also the ridge that locates the o-ring that provides the oil sealing funtionality around the outside of the rocker cover. The outer o-ring is still "stuck" to the cylinder head ...

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ROTAX 912ULS Cylinder head Removal

Image 4

Here we can see the outer o-ring is still "stuck" to the cylinder head and a view of the valves, valve springs and rocker arms etc ...

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ROTAX 912ULS Cylinder head Removal

Image 6

Next remove the four retaining nuts from the cylinder studs. The cylinder heads can now be released. Slid them off the cylinder studs taking care to keep the pushrods in their tubes until you have an opportunity to place them in position on the parts tray. Once they are on a parts tray make a note of their orientation e.g. which end of the pushrod faced into the crankcase and which pushrod belonged to which valve. This is very important so that when you come to re-fit them they can be put back on the correct cylinder on the correct valve and rocker arm. This ensures that components that have already bedded in together get put back together exactly as they were diassembled if needs be ...

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ROTAX 912ULS Cylinder head Removal

Image 7

The cylinder head with pushrod tubes still attached and pushrods still inside ...

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ROTAX 912ULS Cylinder head Removal

Image 10

Note the upper coolant elbow o-ring (red) and the manifold o-ring (black) still in place ...

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ROTAX 912ULS Cylinder head Removal

Image 11

And a view of the rocker arm shaft and rocker arms etc. ...

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ROTAX 912ULS Cylinder head Removal

Image 14

And the cylinder heads with the pushrods removed and stored ...

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