About
About
NEW ESP Race Winning Championship Ported 25.4cc G260PUM top end kit
For serious boat racers, new from E.S.P. is the upgraded 25.4cc PUM top end kit. Porting is upgraded to the big numbers (Duration/Port time area) that wins big races today. The cylinder base is cut to decrease squish clearance and elevate compression needed for getting the most from the stock stroke crank, (still uses stock cylinder gasket). Porting the G260 PUM cylinder’s exhaust port alone to these big duration numbers, while cutting the base of the cylinder, leaves the roof of the port very thin, (about .015” thin), with this particular casting. That can break off the exhaust tunnel from the cylinder during a race. So ESP incorporated the new 34mm Zenoah/ESP “high rev”, and “light weight” piston, (only from ESP as of spring of 2018), which increases the exhaust duration by 5.5 degrees open duration, and allows this cylinder to be much stronger at the exhaust port. The High Rev piston is improved again to reduce compression as little as possible, (less than a cylinder base gasket that is .002” thick), and also lightened by about 4 grams while not losing any strength.
Note: This kit has a tight squish clearance with the stock stroke crank and the stock cylinder base gasket. Because of “part tolerance stack up”, your squish clearance may be a slightly different height than optimal, (.010“/.012“). It is HIGHLY advised you check your squish clearance accurately to make sure your squish clearance is not thinner than .010”. Most of the builds should be about .012” on your cases. If you need an adjustment, (to get the squish between .010” and .012”), you will have to do so with a different thickness cylinder base gasket, (DDM sells .005“, .012“ and .020“ thick copper gaskets. These gaskets are found in the "also purchased with this item" listings at the bottom of this page.) This is necessary for best performance and reliability.
Doug @ ESP is proud to offer “Top Performance” and “Top Quality” to racers around the world for a price that keeps their wallet on the fat side. For quality control and cost reduction reasons, ESP has never farmed out it’s work. All CNC machining, manual machining and hand finishing is done by Doug himself, (the quality freak), insuring that every part that leaves the ESP shop is of top quality and ready for you to win with.
With a 1mm stroker crank and .020 gasket, you can make a 26.33cc engine.
The best way to reach Doug @ ESP is by phone, 7 days a week, from 9am to 9pm Eastern Standard Time Zone. 616-458-8103
For serious boat racers, new from E.S.P. is the upgraded 25.4cc PUM top end kit. Porting is upgraded to the big numbers (Duration/Port time area) that wins big races today. The cylinder base is cut to decrease squish clearance and elevate compression needed for getting the most from the stock stroke crank, (still uses stock cylinder gasket). Porting the G260 PUM cylinder’s exhaust port alone to these big duration numbers, while cutting the base of the cylinder, leaves the roof of the port very thin, (about .015” thin), with this particular casting. That can break off the exhaust tunnel from the cylinder during a race. So ESP incorporated the new 34mm Zenoah/ESP “high rev”, and “light weight” piston, (only from ESP as of spring of 2018), which increases the exhaust duration by 5.5 degrees open duration, and allows this cylinder to be much stronger at the exhaust port. The High Rev piston is improved again to reduce compression as little as possible, (less than a cylinder base gasket that is .002” thick), and also lightened by about 4 grams while not losing any strength.
Note: This kit has a tight squish clearance with the stock stroke crank and the stock cylinder base gasket. Because of “part tolerance stack up”, your squish clearance may be a slightly different height than optimal, (.010“/.012“). It is HIGHLY advised you check your squish clearance accurately to make sure your squish clearance is not thinner than .010”. Most of the builds should be about .012” on your cases. If you need an adjustment, (to get the squish between .010” and .012”), you will have to do so with a different thickness cylinder base gasket, (DDM sells .005“, .012“ and .020“ thick copper gaskets. These gaskets are found in the "also purchased with this item" listings at the bottom of this page.) This is necessary for best performance and reliability.
Doug @ ESP is proud to offer “Top Performance” and “Top Quality” to racers around the world for a price that keeps their wallet on the fat side. For quality control and cost reduction reasons, ESP has never farmed out it’s work. All CNC machining, manual machining and hand finishing is done by Doug himself, (the quality freak), insuring that every part that leaves the ESP shop is of top quality and ready for you to win with.
With a 1mm stroker crank and .020 gasket, you can make a 26.33cc engine.
The best way to reach Doug @ ESP is by phone, 7 days a week, from 9am to 9pm Eastern Standard Time Zone. 616-458-8103