Many bikes, especially classic two strokes like Kawasaki H1, H2, S1, S2, S3, KHs etc had inaccurate ignition marks from the factory, some so bad that if you timed the bike from them you would be holing pistons! Many factory workshop manuals admit this. Many set the timing mark as a piston height before TDC (Top Dead Centre). This means that you screw the applicable adapters into the spark plug hole to hold the dial gauge in the correct place and turn the engine over until the piston is shown by the dial gauge indicates the piston to be at the top of the stroke or TDC. You can then turn the engine backwards until the dial indicates that you have dropped the correct amount eg Kawasaki S2 fires with the piston at 2.4mm before TDC (BTDC) and you can then re-mark the flywheel or back plate correctly. This kit contains a dial gauge, extensions for the dial gauge plunger, adapter for the dial gauge and an extension for this adapter and adapters to fit 10mm, 12mm and 14mm plug holes. This is a professional set but, as can be seen from the photo, the plating on some of the adapters leaves a bit to be desired. Whist we don't like the quality of finish it is a perfectly useable product at a very good price.