2/4 stroke presentation

Work experience

Motor of bike with camshaft cover removed. To time the engine, the 2 lines have to be horizontal, while the piston is at TDC. However it is easy to time it with the camshaft 180 degrees out.

This is the flywheel. Here we can (just) see 2 marks. T, which is TDC and F, which is fire. The dirrerence between these 2 marks will be approximately 5 to 8 degrees.

This is the flywheel assembly from the side. We can see the timing mark above the flywheel, to line up TDC.

This is the flywheel cover, which has the alternator mounted inside it. It also has starter moter gears mounted there too.

injector pipes off a tractor

Engine of the tractor



engine with rocker cover removed



Rockers on shaft after removal

Starting to lift head off. The head studs stay in the block, so is difficult to have to lift the head up evenly.

Block with head removed

Cylinder head after removal

Aniter tractor which we had split to remove the clutch. This is the back half, looking at the gear box.

This is the front half, looking at the motor. The flywheel would be here but we had removed it.

The tractor. To get at the bolts at the top of the bell housing, we had to undo the cab mounts and jack the cab up.

We split the tractor about  2 to 3 feet. The motor has been jacked up on a jack with wheels, which sits in a track on the ground, (can be seen in the photo) when all bolts etc are removed, the front half rolls forwards on the jack and front wheels.

Frost plug which came out of cylinder head.

Flywheel out of tractor

Flywheel after it had been refaced. This was very worn.

Clutch plate.

Pressure plate.

Pressure plate again.

Piston out of one of our tractors, as you can see from the chunk missing, the engine did not run very well.

Another piston out of our tractor.

Looking down at the cambelt assembly on the bosses car. We had to replace the water pump.

Removed the water pump pully.

Looking up at the crankshaft pully.

I removed the crankshaft pulley and cambelt covers.

Looking down at cambelt assembly.

Torquing down head bolts on the tractor engine.

Setting valve clearances on the tractor.

Practical Work



The block of the engine after we removed the head.



Checking the head for warpage using a straight edge (steel rule) and feeler gauge.

Measuring the overall length of the valve spring using the verneer caliper.

Measuring the lobes for cam lift using the micrometer

Measuring the strength of the valve springs. All of my springs were not springy enough and shims need to be added.

Checking bearing journal clearance on camshaft using plastigauge.

Torquing down bearing caps using torque wrench.

Inserting valve, valve springs, collets and washers using that special tool.

Torquing up cam pulleys using Jiejun's electronic torque meter. Here I forgot to put the plate behind the pulleys so I had to take the pulleys off, put the plate in and put the pulleys back on.

Cylinder head with the plate and pulleys on.

The assembled head.

Removing the water pump from the block.

Bottom end with the sump removed.

Oil strainer

Removing the cambelt pulley. I put a block of wood between the crankshaft balancer and the block to prevent the crankshaft from turning while I undid the nut.

Removing the oil pump.

Measuring the depth of the cylinder at several intervals so I can draw a graph as an exercise.

The assembled cylinder head.

The engine block with everything removed.

The engine block with the pistons removed.

The pistons, crankshaft, and bearing caps lined up on the bench.
Keeping them lined up makes it easier to remember where each component
goes and also keeps the bench looking tidy.

One of the removed pistons.

Checking a conrod for being bent. This one is bent beyond specs as you can see
the bottom prong bit does not touch the plate, whereas the top one does.





Checking the crankshaft main bearings for taper and ovality with a micrometer.

Checking the crankshaft for run out using the DTI.
This crankshaft had virtually no run out.

Torquing down the big end bearing caps. I also checked the journal clearance
 using plastigauge.

Torquing down the main bearing caps. I also checked for journal clearance here using
the plastigauge. All clearances were good.

This is the finished engine that we assembled after we have taken all of the measurements.
We found that most components were in good condition, except for one cylinder that had
some scuffing on the thrust side of the bore.