Honda TRX 250R Porting & Head Mods DRI has spent 1000's of hours testing, doing R&D on 2-stroke port types and designs. There are no quick read manuals to explain the complexity of 2-Stroke porting. Data must be gathe

Suzuki LT 250 Porting & Head Rechamburing DRI has spent 1000's of hours testing, doing R&D on 2-stroke port types and designs. There are no quick read manuals to explain the complexity of 2-Stroke porting. Data must be gathered

Suzuki LT 500 Porting and Head Modification DRI has spent 1000's of hours testing, doing R&D on 2-stroke port types and designs. There are no quick read manuals to explain the complexity of 2-Stroke porting. Data must be gathered

Yamaha Blaster Porting and Head Rechamber DRI PTR ported cylinders have won more Pro ATV Races and Pro ATV Championships than any other company in the world over the last 2 decades

Banshee NATIONAL Porting & Head Rechambering No company in the indusrty can match DRI's record for 2-stroke ported cylinders. PTR Banshee cylinders have set the standard for both racing and recreational usage