Bombardier SeaDoo 1996 factory shop manual, Page 66Get this manual
Section 04 ENGINE Sub-Section 02 (TOP END)
Boring Precaution
In its stock configuration the RAVE valve guillotine has minimum of 0.5 mm (.020 in) clearance to the cylinder bore measured at the center line of the cylinderThis is the minimum production clearanceThere is only first oversize piston available for the 787 engineThat piston is 0.25 mm (.010 in) larger in diameter than the stock pistonWhen the oversize is installed, the guillotine will have minimum clearance of 0.375 mm (.015 in) with the cylinder boreThis is the minimum operating clearance the guillotine should be used withClearance less than 0.375 mm (.015 in) will require reworking of the guillotine to achieve the proper clearance and radius