| I already have the engine stripped and all the relevant parts
are on the workbench. As usual, I have placed to parts in order. When I
strip any machine I usually place the first nut, bolt washer, on one side
and to the rear or my workbench, and work forward. It stops me from losing
parts, it also gives a good indication as to what the part does and
where it goes on the rebuild without having to referring back to the manual
|1. The crank, con(necting) rods, and big end shells.
The con rods, shown top left, and there are two in site in the
crank itself. They have two bearings each, these are called the big end
shells, and they fit firstly into the con rod, then the con rods are then
placed onto the crank itself.
When doing up the bolts of the con rods you have to tighten them
exactly, too loosed and they will fall off, too tight and they won't turn,
or seize up when used.
Big end shells should always be replaced in the same con rods
they came from.
||2. The lower crankcase.
Now the crankcases are clean, the main shells are placed into
their correct position, top left. There are four in the lower cranks in
this engine, three at the front left and the last front right.
You can also see the gear selector forks (lower part of large
photo.) I have checked them and are free of damage or wear. These move
the cogs on the gearbox shafts and change gears
|3. The upper crankcase, and crank.
I have cleaned the upper crankcase, then placed the five main
shell bearing in place. Then placed the crank into position, then placed
the last of the lower main shells into place and loosely done the two bolt
and clamp which hold the crank into place, later I'll have will have to
tighten them to the correct torque.
||4. Gear clusters.
I have checked the cogs of both shafts and found no damage, so
I don't have to take either of the clusters apart. The top one is the shaft
that goes through the clutch, the lower one is the shaft which, eventually
will have on the cog which hold the drive chain.
The next step in to place both shafts into place into the
|5. Placing the main output gear cluster and shaft into position.
First you have to align the two selector forks so they fit into
the two grooves between the second and third cogs, then the fourth and
fit cogs, then gently the shaft into position into the lower crankcase.
the hole in the bearing on the left of the shaft shown here should point
up, and it will be align up with a dowel in the upper crankcase.
||6. Placing the main input gear cluster and shaft into position.
Again, position the selector fork so that it aligns up with the
groove into the input shaft between the third and fourth cog, then gently
lower the shaft into position. again, make sure the hole in the bearing
in the end of the shaft points up so it aligns up with the dowel in the
|7. Preparing to join the two crankcases.
Make sure all dowels are in the correct place, and then lightly
smear a bit of sealing compound onto the lower parts of the crankcase,
where the two cases meet. Do not too much, as when the crankcases are bolted
together, the excess can get into oil ways and cause problems.
||8. Joining the crankcases.
Gently lower the top crankcase, with the the crank shaft itself
in it. Make sure the dowels mentioned earlier are located correctly, and
the semi circular retaining clips are located in the two bearings of the
gear shafts, fit flush with the groove top crankcase.
Now put in a couple of the crank case bolts into the top crankcase,
just finger tight for now, just to keep the two cases together before I
begin on the crank case bolts sequence. These bolts are go in sequence,
and have to be tightened exactly.
|9. Installing the clutch, soz got no photo's of that, camera run out
of battery power, and I wasn't waiting.
10. Alternator drive chain mechanism.
place the chain over both cogs and hold them apart and slide
both splines onto the shafts together.
Add the two washers and bolts, then tighten.
||11. Alternator drive chain tensioner.
This you have to hold in the position as you can seen in the
photo, it is spring loaded. and there are two washers on the back side
of the two washers and they have to be in position as you position the
tesioner. The two bolts should be treated with thread lock, as if they
come undone, it will smash into the clutch basket.
Once this is done the gasket should be a small amount of gasket sealant
and placed over the clutch casing which then be placed into positioned
|12. Oil pump.
Now the oil pump has been cleaned and the dowels and oil seals
have been correctly, the oil pump can be placed onto the plate, which will
fit up and into the sump.
||There is a small key on both sides of the pump itself, these have to
be positioned correctly, or the pump will not sit in the crankcase properly.
They run up/down if you have the engine right side up or, upside down.
There is a small oil seal on the other end, which should not be forgotten.
|13, The five bolts which hold the oil pump casing have now been tightened.
The dowels and "O" ring seals are being placed into position, as with the
first of the oil tubes feed lines. The large circular oil seal in the top
left will eventually hold the oil filter and casing.
||14, The oil sieve has now been put into position, and the second of
the two internal oil tube feeds.
15, A small amount of gasket sealant now has to be smeared the outside
edges of the casing then the gasket should be positioned before replacing
the sump plate itself.
|16, The gear selector casing has to be placed into position by 9 screws,
then place drive sprocket and the tab washer are put onto the splines into
the shaft. Then do do the nut itself is tightened, before bending up the
edges of the tab washer, this is to stop the cog nut from undoing itself
when being used.
17, Water pump. This has to align the shaft with the "key" on the oil
pump. Make the "O" seal is not damaged.
||18, The alternator.
The alternator, which generates the electricity for battery,
lights etc. has four splines which fit into four cush drives into the crankcase.
There are 3 bolts which hold them into place.
(cush drives have rubber inserts)
19, The starter motor.
This sits just behind the the alternator, and the splined shaft
fits in easily enough, again make sure the "O" seal is good condition,
if so, tighten the two bolts that hold in position.
|20, Connecting the piston.
Firstly turn the engine so that two of the con rods are as high as
they can be, then feed the pin partly into the piston, then align it with
the top of the rod (sometimes called "small end"), then push it through.
Have left one circlip (held in my fingertips in photo) on the other side
of the piston, so the pin cannot fall through. Then place a cloth under
the piston, and cover the gap underneath to stop from the other circlip
from falling into the sump. Then fit that in the groove into the piston
to the pin slipping this side.
If possible always use the same piston and gudgeon pin (wrist
pin) with the same connecting rod.
||Rings, pins & pistons
When buying rings they usually have a mark on each of the rings,
the mark goes on the top side. The oil ring is made in three pieces and
goes in the lowest of the three grooves.
For a bigger, clearer view click on the photo.