DIYMINIBIKES

Product Specs:
Clone Box Stock (BSP) Engine Inspection Tech Gage
.815 Must-Go Spring Installed Height Gage
Official Rix Technical Inspection Tool — MADE in USA
Valve spring installed height is the distance/opening between the lower retainer and the upper valve retainers on cylinder head. If there is no upper retainer this measurement will be taken directly off the spring pad on cylinder head.
The installed height distance needs to stay as close to the must go gauge dimensions to achieve the most valve spring pressure possible with a stock spring. The larger the distance the less spring pressure the valve will have.
Installed height distance will change from normal engine operation or if valves, lower or upper retainers are replaced.
2014 rules allow valve spring retainer shims to be used for tightening up installed height that is too large.
Please consult rules for your race sanctioning bodies for installed height requirement.