Next up, the head shims had to be fitted. Six screws hold the head on [Note: One screw is between the valve rockers] so that came off in a jiffy.

The shims just sit between the head and the barrel. You actually need to fit them in the head first, it was just easier to get a photo of them sat on top of the barrel.

Getting the head back on was fairly easy but the push rods wouldn’t line up with the rockers for me so I ended up taking the rockers off (only one screw) and aligning everything carefully. None of this was difficult and took not many minutes at all.

Having shimmed up the head, the valve clearances were now huge, so they had to be brought back within tolerance (0.04mm-0.1mm). This is a simple matter of loosening the little lock nuts on the top of the rockers and then adjusting the screws down until the gaps are within tolerance. I checked the gap with a pair of feeler gauges (a 0.05mm and a 0.1mm). I managed to achieve a loose sliding fit on the thinner gauge and a tight fit on the thicker gauge. Again this only takes a short while.

The glow plug needs to be replaced with a spark plug. That was just the easiest job on this project.

The next job is the set the timing. The instruction pages that came with the CDI kit had an angle gauge printed on them so you just have to cut it out and stick it to some cardboard.

Just set the engine to Top Dead Centre and clamp the gauge up with the prop nut to read zero against some kind of fixed pointer.

The instructions said to set the timing between 28 and 30 degrees before TDC, so I set the angle to 29 degrees as my starting point. The prop driver and crankcase were marked at TDC and 29 degrees before TDC.

The sensor holder was then rotated so that it lined up with the magnet when the engine was at 29 degrees before TDC.