Assembly Part 3

This part will deal with the assembly of the upper castings the big end bearing and all the parts associated the cylinder and piston.

Also the assembly of the cylinder head and all associated parts, fitting the fuel tank.

Before fitting the ring it was checked in the groove and found no tight spots  in the top ring groove in fact it was a bit sloppy but let's ignore that for the moment. The second grove was much better.

The rings were then put onto the piston and the gap set at 180  degrees to each other.

The shells of the big end bearing were checked to be marked and in their proper position as made including the location of the oil way.

The piston was fitted to the connection rod and the big end tightened up.

The upper main castings was then oiled and the piston inserted and alignment checked before marking the lower main casting where the fixing stud were to be tapped into place.

After this temporary assemble the big end was taken apart and set aside with the upper casting and work began on drilling and tapping.

The studs were fitted and the main upper casting and piston brought to the engine and set upon the studs. With all well the nuts were placed on the studs and tightened down. The crank was now rotated so the the big end could again be fitted.

Two hole to take a magneto had been drill and these were temporary filled with M5 bolts.

With all the tops parts tightened down the mail cylinder oiler was put into position.

However no is the time to fit the cylinder head and all its parts.

The first part to fit is the head gasket  and slide it onto the cylinder head studs.

Not the cylinder head its self can be assembled.

The bungs are put in place where holes were drill for the through ways to the ports.

Both the valves are put in place and held with their washer caps and split pins making sure that the weak spring is on the inlet valve and the strong on on the exhaust valve. A little oil on the valve stems is a good idea !!

Then on goes the rocker making use you have it the right way round.

If the timing plate is all in place then so should the push rod for the exhaust valve.

With this checked the head can be slide on making sure that you include the rocker push rod and then tightened down. The nuts are not tightened in numerical order but one then miss one etc and the tightening down is done evenly so that the head will sit parallel to the face of the casting and not cocked up.

Fit the bung through which the water from the cooling the engine will exit and make sure you have an "O" ring to seal it so do not tighten too tight.