Part 26 By Vince Cutajar

I decided to test the ignition system using the Kiwi contact points and the spark plug in the cylinder head. Hooked everything up temporarily using hook up wire (looks like spaghetti junction) and connected it to a car battery. Turning the contact point cam by hand, I managed to get a decent spark in the plug.

After having a go at case hardening the wrist pin I made two brass end plates for the wrist pin which were eventually pressed in. Also the two piston rings were fitted on the piston and the piston fitted into the cylinder. It was not difficult to press the piston into the cylinder and the miniature ring compressor I had made was not used.
I was going to fit the crankshaft but then I remembered that every time I needed to untighten either the flywheel nut or the special nut retaining the gear I always had problems because I could not stop the crankshaft from turning. So I milled two flats on both threaded extremities of the crankshaft to lock the shaft from turning with a spanner.
I then fitted the con rod to the crankshaft  and then mounted the crankshaft to both halves of the crankcase.
After rough timing of the camshaft, and also fitted the ignition timing cover with its associated mechanism,  set the ignition cam position.

I also made up the H.T. lead using the NGK resistive spark plug cap.

All that remains to be done is grinding the valve seats.

I fitted the valves into the head using 600 grit grinding paste and an MT3 drill chuck. Put the valve in the head and clamped the valve from the end of the valve stem with the drill chuck. The inlet valve did not need a lot of work but the exhaust valve needed a fair bit of work.

Used a vacuum hand pump to check for valve seating. I then gave the head and valves a good cleanup in the ultrasonic cleaner to remove any traces of the grinding paste.
I re-assembled the cylinder head and bolted it to the engine.

I decided to try and start the engine to see if at least it would make any encouraging noise. I connected a plastic tube to the carb and filled it with fuel (unleaded gasolene) and gave the engine a twirl with the electric drill. Bad news. Not even the slightest indication of combustion in the engine.

Decided that further work on the engine will stop until I troubleshoot what is the problem.

Started off to check if the spark plug is working. Took the spark plug out and ran the engine again. Yes there is a spark but the problem is I do not know how a good spark should look like. Replaced the ht lead (which had a resisitive cap) with common wire and tried again. Again same spark (I think). Checked the plug gap and it is set at 0.5mm. Should I change this gap?

I increased the spark plug gap from 0.5mm to 0.6mm and had a closer look at the colour of the spark. It is whitish with blue edges.While turning the engine with the hand drill to see the spark, I realized something. OMG. I had been turning the engine in the wrong direction. After some unprounoucable phrases I cooled off a bit and put some fuel in and gave it another try. It still did not start but I think at one time I heard an encouraging splutter coming out of the engine.

I removed the cylinder head and started lapping the valve seats with toothpaste to remove the small leak that they had.

Eventually  the engine ran when trying to start with the electric drill but is not self-sustaining. My friend said that the spark and the timing are okay but just needs a bit more compression. When making the crankcase, I left the cylinder platform about 1mm higher to reduce the compression. Westbury suggested that a lower compression would make an easier starting engine.

While dismantling the engine to mill off that extra height on the crankcase I had another idea. Why not make a new longer piston and make it even tighter with no clearance at the top and make it 1 mm longer to cater for the extra material on the crankcase cylinder platform. 

Made the new piston from bar stock, connected the fuel line to the carb and, believe it or not, my electric drill gave up the ghost.

Bought a new electric drill. Hooked it up to a plastic pipe. Filled the pipe with fuel (no tank yet) and gave it a twirl.

OMG it runs! Only for short periods, as it runs out of fuel quickly, but at least now I know that it works. Unbelievable.

Now I can continue and finish it up. Still need to do the exhaust pipe, a base and some sort of fuel tank.

I visited an acquaintance with my engine, hopefully, to get a base done for it.

He is a retired wood-turner but still goes to his shop to tinker and do the odd job. He is an avid plane-spotter and sometimes I visit him and talk about his favorite subject.

I entered his shop holding my Kiwi in my hand with the temporary MDF base I am using. After commenting favourably about the engine he then said that that base will not do and went scurrying to the back of his shop. Came back with a piece of oak and said that this should do for the base. Thirty minutes later I was going out of his shop with a nice base for the Kiwi and the best part is that he refused payment for the job. My lucky day.

Decided to use the brass flange I previously used as a template. The tube is a tight push fit into the flange.
For the exhaust pipe, I annealed, bent, annealed and bent.  I was getting a flat area on the outside radius. Did not like it. So I redid it and bent a little less between annealing operations.
I silver soldered the exhaust pipe to the flange and pickled it in white vinegar. I cleaned it up  and fitted it to the cylinder head , gave the engine a run and it gives a nice motorcyle noise with the exhaust pipe.

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