YZ125 BIG BORE CYLINDERS

PORTED AFTERMARKET CYLINDERS for 2005-21 YZ125,134,144 $350-$550

USPS PRIORITY MAIL INCLUDED!

These aftermarket cylinders are designed by Eric Gorr for better reliability over original cylinders. Special design consideration was given to the exhaust bridge area on the small bores and porting on the big bores. Longevity is all about casting design and tooling. These cylinders don't have stress-risers around the exhaust port like a OE Yami cylinder so they don't form death-cracks that can't be repaired by the popular plating companies. The casting process is state of the art with 3D printed polymer lost foam tooling for each cylinder. 

124cc $350
Ported for more mid to top in comparison to stock Yamaha and the exhaust bridge is strengthened for better reliability. The exhaust port height is 28mm and the transfer port height is 42, advanced 1mm over stock. Cylinder porting by Eric Gorr in Wisconsin
$350 USPS included

134cc $550
Ported for mid to top end. This cylinder is a replacement for top ends previously converted to a 134cc. This assumes that the powervalves and cylinder head have been modified for the larger bore size. Cylinder porting by Eric Gorr, cylinder plating by Millennium. Made in Wisconsin USA
New OE heads modified to 134cc available along with the piston and gasket kits.
$550 USPS included

144cc $550
Ported for a wider powerband, mx & off-road mix. This cylinder is a replacement for top ends previously converted to a 144cc. This assumes that the powervalves and cylinder head have been modified for the larger bore size. Exhaust bridge widened, Cylinder porting by Eric Gorr, cylinder plating by Millennium. Made in Wisconsin USA
New OE heads modified to 144cc available along with the piston and gasket kits.
$550 USPS included