2015 ec250 squish and port timing

[ljdb]

Hey guys pulling down my top end and thought to check the squish and piston to port location at bdc. Motor has never been apart. Everything ive researched says piston level with exhaust port is better for top end power and above is better for low down grunt. Now my piston sits below the exhaust port at bdc but level with the rear transfer ports. I havent measured the squish yet but looks to be on the large side. Will lowering the barrel to make the piston at bdc level with the exhaust port and then also covering more of the transfer ports be worse for power. Im chasing more low down grunt without sacrificing to much top end. Thanks in advance

 

[Zman]

The piston spends very little time at BDC and the more important timing variable is based upon the top edges of the ports. If you want more bottom end lower the cylinder by using thinner base gaskets. Another option is to have the base of the cylinder cut to further change the port timing.

Squish and compression will make a significant difference across the rpm range. You can also increase you power at lower RPMs by increasing your ignition timing a few degrees.