84 Update Porting Specs


Using a hand grinder, grind away the port material shown in the shaded sections of the illustration, being sure to match the specifications given.  Note that the figures in brackets represent approximately the amount of material to be removed.  This is for initial layout only.  The final dimensions of the ports should be matched exactly to those specifications shown.

Be sure to chamfer ports.

Grind material from the transfer port as shown in the illustration.

Note:  This illustration refers to the transfer port windows leading into the cylinder; this is not at the base of the cylinder.  This is transfer port modification must be done correctly to obtain indicated horsepower increase.


Machine 0.3mmof material from the cylinder head gasket surface.  For best results, check the total volume of each combustion chamber; the volume should be 26.3+- 0.2cc.  If either combustion chamber volume is outside this range modify accordingly. 


The addition power output resulting from these engine modifications requires changes to the engine's oiling system.  For 1984 ~ 1986 V-Max models (VMX540H/J/K) you may either retain the standard oil pump and use premix fuel at a ratio of 50:1 or change to the 1983 oil pump.  For 1983 models, no change is required.  Note that this additional lubrication is necessary to ensure connecting rod and crankshaft bearing operation, not to prevent piston seizure.