TOTAL POCKET BIKES TUTORIALS

WHAT IS SQUISH?

This is an overlooked aspect of a motor and it can make a huge difference not only to performance but also to reliability.

Before we look too much into it we'll start with some basics.

WHAT IS SQUISH?

Squish is the distance between the edges of the piston to the dome itself. The smaller the distance, the more heat is generated but also the motor responds better by having increased performance and better response. Heat though is an issue with motors and excessive heat will damage the piston and ring quite severly.

Some bikes though come with a squish that is too big, a perfect example of this is the Blata rep bikes. My blata rep bike had a squish of more than 2mm without even running a gasket which is terrible.

Each motor though generally has a good figure to sit around at which is between .6mm to .8mm. Some owners have even got theirs down towards the .3 to .4mm mark but expect to be rebuilding the motor a lot sooner.

HOW DO YOU SET THE SQUISH?

The squish is set by removing the spark plug and passing a piece of solder shaped in an L pattern. The idea of this is to lower the bottom of the L into the head so it touches the inside of the cylinder wall. The next step is to use the pull start on the bike to make one revolution of the motor, you will feel the solder squash down (hence the name squish). Now measure the edge of the solder with a pair of verniers and you will have your squish figure in mm.