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Accu-Products' Deck Height Setting and Timing kit with timing mark alignment block.

Deck height (the distance from the piston crown edge at TDC to top of cylinder) is a critical aspect of any two stroke competition machine, especially the later V-twin TZ Yamahas. Many a TZ owner (the author included) has struggled with feeler gauges, straight edges and the like attempting to get an accurate deck height reading to allow adjustment of squish clearance to a desired amount utilising different thickness base gaskets. Trying to do the job accurately this way (without the proper equipment) is "Mission Impossible" really.

We recently tried out one of Accu-Products' "Deck Height Setting and Timing kits" and came away thoroughly convinced that this was the way to go. 100% accuracy and confidence that one has it right this time is worth 100 times the cost of the kit. Nothing could be easier and once again Rick Merhar and his team at Accu-Products have proven that the simplest inventions are invariably the best!


The kit comprises a quality metric dial gauge with extensions as well as a precision machined nylon spacer block and timing mark alignment block all contained in a neat, purpose built timber storage box.







Checking deck height is as simple as:

  1. Screwing the dial gauge adaptor into the block and then the dial gauge itself into the adaptor.
  2. Holding the block firmly onto the cylinder's top surface with the dial gauge tip on the cylinder surface as well (not the piston crown just yet)  then zero-ing the gauge.
  3. Turning the block across so that it's outer edges remain in contact with the cylinder surface but the dial gauge tip contacts the piston crown directly above the piston pin (to eliminate any piston rocking error.).
  4. Rotate the motor until TDC (top dead centre) is found for the cylinder you are working with.
  5. Take this measurement, this is your deck height, your accurate deck height. Easy as that!


The photo shows the final step in the process and indicates that this particular cylinder has a 0.1mm positive deck height in this position.

 Pretty impressive!

The kit doubles as an ignition timing adjustment tool, the adaptor also screws straight into the spark plug hole allowing the dial gauge to be utilised when setting your timing statically. A special "timing mark alignment block" has been provided to eliminate any parallax error in reading of the marks by eye. They've thought of everything!


For more information on the kit (or for all your racebike setup requirements) give Rick at 202-Racing a call on:

        1-877-ACCU-MIX    (in the USA only).

or    1-440-356-1202     (001 International)

or visit their website for more information.

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03/23/08 06:38 AM +1000    

This website Greg Bennett 2002.