Changing the timing chain
of a big Guzzi engine
This will be an instruction, how to change
the timing chain of a big Guzzi engine. Considering the engine still in
the frame it is usually only necessary to remove the long front engine
bolt. On flat floor it is even not necessary to remove the oil out of the
engine, because the oil pan is deep enough. So take the speedo cable off
and get ready, hopefully with a soft cushion under your ass.
If you change the timing chain, I recommend
a better than the original tensioner, which is not really a tensioner but
more a placeholder for one. There is a really good tensioner available
with a spring preloaded plastic guide, which gives your engine accurate
ignition timing and stabile idle. In Germany it is called Stucci tensioner.
Besides this you need as spare parts:
-
27mm nut for the camshaft
-
special nut for the crankshaft gear with security
washer
-
new timing chain
-
new gasket for the front cover
You will need these tools:
-
3mm Allan head (for Saprisa alternator)
-
5mm Allan head
-
6mm Allan head
-
8mm hex nut
-
13mm hex nut
-
27mm deep socket nut
-
special tool for the crankshaft nut
-
a 55mm long 6mm thick pin and a 30mm long M8
bolt
-
a chisel and a hammer
The last preparation should be to turn the
engine in left TDC position. Take your time and follow the instructions:
-
take off the alternator cover
-
pull off the cables and remember the positions
-
take off the stator after taking out the three
bolts holding it
-
turn out the bolt, which holds the alternator
on the crankshaft
-
take the 6mm pin, put it in the hole and screw
the bolt into the alternator as long as the alternator falls off
-
take out all bolts of the front cover (12)
-
take the front cover carefully off, don't destroy
the gasket surface, there are two guide pins, so don't hammer too hard
-
check if the marks on the crankshaft and camshaft
gear are in line
-
use a power wrench or a chisel to loose the
27mm nut of the camshaft (top)
-
use the special tool to loose the special nut
on the crankshaft (middle)
-
loose the 13mm nut on the oil pump
-
are the marks on the gears still in line?
-
take off all three bolts and pull the whole
assembly of three gears and the timing chain out
-
be careful, on the shaft of the crankshaft and
the oil pump there are little metal guides, don't loose them
-
take out the old tensioner, as long as the bolts
doesn't hold the bearing, you can leave them out
If you now want to continue to take out
the camshaft, you have first to take off both cylinders.
Then you would be able to check the camshaft surface. If you only want
to change the chain and the tensioner, you can do as follows:
-
take the new tensioner, take off the little
8mm nut and pull the tensioner a little bit from the shaft, so that the
spring stays just on the shaft
-
now bolt it into the housing in the appropriate
holes
-
take the whole package of three gears with the
chain and push it onto the shafts, make sure that the two metal guides
are still in place, the pin on the camshaft wheel is also in the gear?
-
Secure them all with the different nuts, don't
forget the security washers on all three
-
Push the tensioner in the gap between the chain
and the housing, tight the 8mm nut of the tensioner
-
Tight all three nuts on the shafts, bend the
security washer on the crankshaft so, that it locks the nut
-
If you want to change the sealing of the crankshaft,
now it's the right time to do so (grease the inside a little bit after
mounting
-
Clean the surface of the housing from the old
gasket and the oil
-
Put on the new gasket and push the cover into
place
-
Tight the bolt all around
-
Clean the conus on the crankshaft and the alternator
and put one on each other
-
Put the long bolt of the alternator through
and tight it
-
Mound the stator and put the three bolts in
-
Close the alternator cover, put the speedo cable
in place and that's it
DONE
Eric Koch, 1999