New Honda Pistons - Not Legal in 2008

From time to time, Honda Engines updates the parts used in their GX390 engine - the only powerplant used in MMRA minicup racing.  For example, in 2006 they updated the crankshaft and rod used in the engine.  Generally, these new parts are legal for use in MMRA racing - when the change happens in the off-season. 

In this case, the new piston design came after our 2008 rulebook had been released, and our season had started.  Many competitors have already freshened their engines for the season, and they planned to run all year before having engine work done again.

As such, MMRA will not allow the new piston to be used in competition during the 2008 points season.  Racers who buy new engines in the middle of the season will also have to purchase an "old style" piston to put in their engine - although they will then already have a new piston ready to go when it becomes legal for use.  This is the best way to minimize costs for the majority of our racers, while ensuring a level playing field for everyone.  Old style pistons are still available to purchase.

The old and new pistons are pictured below.  The photo shows the new piston on the right having "shorter" rings, which are also located higher on the piston.  In addition, the new piston is engraved with "ZF6W01" whereas the old piston is engraved with "ZF6W0".