Cylinder Removal

TAKING OFF THE CYLINDERS OF A BIG GUZZI

This will be a step-by-step guide to take your cylinders off and back on again. For this job you will need the tools as listed:

5mm Allan head socket
8mm Allan head socket (80mm long)
10mm Allan head socket
10mm socket (M6)
13mm hex open end(M8)
17mm hex socket (M10)
piston ring compressor
torque wrench

Obviously it is necessary to remove the exhaust system and the carburetors with the intake manifolds. Last preparation is the removal of the oil line behind the cylinder.

We start with the left cylinder:

Take off the valve head cover
Remove both spark plugs
Bring the piston in TDC, this is the area, where both valves are closed and the ignition takes place

To do this, turn the engine either with the bolt in the alternator (clockwise from the front) or turn the rear wheel in fifth gear (I personally prefer the rear wheel, spares you work), first the outlet valve moves down and up again, then the intake valve does the same, outlet again and so on; after the intake valve has moved and is closed (rocking lever is up again), you have TDC (if you've turned the engine in the right direction J), it should be possible to move the valves. I use a little screw driver in the spark plug hole to feel when the piston is coming up

Loosen the adjustment nuts of the valves
Take out the 10mm fixing bolts from the rocking lever
Take out the shafts with the rocking levers (remember the position of the washers and springs)
Take out the push rods, check if the pins on the upper and lower ends are still tight in the rod, if not replace
Take out the four 17mm nuts which hold down the rocking lever bracket
Remove the rubber rings on the four studs
Take out the 10mm Allan head screw on top of the head (mostly very tight)
Take out the 17mm nuts below this screw and the other at the spark plug
Remove the cylinder head
Remove the cylinder
Remove the gasket and the two little rubber rings on the upper and lower stud

Destruction is done, now there is time to do something useful, at this point in time you can check some things visually.

Take a look into the cylinder, are there still signs of the honing to see, that's good, means the surface can keep the oil for greasing. Clean the cylinder.

Is the piston OK, are the rings broken?

You can check if the valves in the cylinder head close tightly by putting the cylinder head upside down on the table and fill the combustion chamber with gas. In the intake and outlet you can see, if there is moisture running down the valves. Better don't use a lighter for this :o) . You can clean up the combustion chamber with a rotating brass brush for you drill machine.

Take the plungers/lifters out, check the bottom side, which is running on the camshaft, if there is any pitting. That is most likely and I recommend to change them, otherwise it will destroy the camshaft.

You can't check the camshaft without turning the engine, what I wouldn't recommend. If you take a look into the holes, where the plungers were, you only see the ground circle of the camshaft.

After you have taken off the piston rings (carefully, perhaps you need them later on), cleaned the surfaces from the old gaskets and the oil, you can mount the rings. Mount the three new rings (if one breaks - they are not out of rubber - you have as spare ones the old ones). There are three rings, the lower one is the oil ring and the upper two the compression rings. The middle one is not symmetrical, the little groove has to show to the bottom, the upper compression ring is symmetrical. Bring the rings in a position, where the openings are showing in different directions, 120 degree difference would be perfect. So you will have minimum bypass loss.

Now you can build up the engine again:

Put the plungers back in place
Put the foot gasket and the two little rubber rings onto the clean surface (check if all holes are free)
Use the ring compression tool to compress the rings
Lubricate the cylinder a bit and push it over the piston (you can see through the cylinder if it fits)
Put the head gasket in place (check if all holes are free)
Put the cylinder head on
Push the four little rubber rings over the studs and mount the rocking lever bracket
Tight the bracket with the four 17mm nuts a little bit
Put the other nuts in place and use the torque wrench to tight all six down in three steps (30, 40 and 43 Newtonmeter; I don't know how much that is in ...pounds) in zig-zag shape
Close the hole at the upper end with the 10mm Allan head (perhaps a new rubber ring?)
Put the push rods into the holes
Mount the rocking levers and tight the 10mm screws
Adjust the valve clearance
Fix the oil line behind the cylinders
Close the valve cover

DONE (with the left cylinder)

Now you can do the same job on the right cylinder, first search for the TDC for the right cylinder and start the same sequence.

If you have finished both cylinders and reassembled your bike, you can go for a ride for some miles to heat up the whole engine. After that leave it to cool down over night. The next day you can check the torque of the nut by removing the spark plugs, the valve cover and the rocking lever bracket. In my opinion it is not really necessary to check the torque after 600 miles again, but it is not absolutely wrong. Adjust the valves and you are ready to go.

Eric Koch, 1999