WE ARE PROUD TO PRESENT S3 PISTON KITS 

 by Vertex   

      DOESN'T FIT TRIALS MODELS   

TOP END OVERHAUL KIT FOR 2021-2023 RIEJU MR 300 MODELS ,1999 THROUGH 2019 GASGAS EC,XC,MC,DE,SE,SM,300 MODELS

INCLUDES: S-3 "A" 71.94MM (PISTON KIT (PISTON,CIRCLIPS,RINGS & PIN),WRIST PIN/NEEDLE BEARING,HEAD O-RINGS,(INCLUDES TWO BASE GASKETS .3MM & .5MM) BOTH POWER VALVE GASKETS,WATER OUTLET GASKET,EXHAUST FLANGE GASKET,A PAIR OF HIGH QUALITY VITON EXHAUST O-RINGS . On Jul-10-11 at 11:52:04 PDT, seller added the following information:

Important Note:  if you have an S-3 (red anodized) head with changeable domes on your bike the dome seal/oring around the spark plug hole is included in the gasket kit

We also carry the S-3 o-ring kits separately if you want some spares.

THIS COMPREHENSIVE KIT INCLUDES EVERYTHING NECESSARY TO REBUILD YOUR TOP END PROPERLY.  LET US KNOW IF YOU WANT TO ADD ANYTHING.  WE STOCK A FULL COMPLIMENT OF HIGH QUALITY BEARINGS & ROD KITS ETC. TO FULLY OVERHAUL YOUR ENGINE .      

Cast vs. Forged

What’s better and why:

Because of a cast piston’s ability to contain higher silicon content compared to forged pistons, and because two strokes have lower cylinder pressures when compared to four-strokes, cast pistons are ideal for two-stroke engines. Vertex pistons are gravity cast from an aluminum alloy with 18% silicon content. Silicon is important because:

• It decreases thermal expansion, which changes the geometry after the piston reaches operating temperature. With low thermal expansion characteristics, Vertex pistons can be run at tighter tolerances compared with forged pistons. This creates better power and performance, also making them less susceptible to rattling or breaking.
• Silicon gives the pistons better wear characteristics and prolongs piston life by decreasing wear on the

 S-3 2-stroke pistons are cast for maximum performance and 18% silocone content for strength and durability. 

The skirts are moly coated for increased lubricity and easy break in

WE ALSO OFFER ENGINE REBUILDING SERVICES 

CUSTOM PPORTING AND HEAD MODIFICATIONS               

Improper warm-up-A great way to cold-seize the engine. This also kills crank and rod bearings, not just forged pistons.                      

Anytime you rebuild the top-end, you have to measure the ring end-gap, and file the ring ends if necessary. I have rarely seen rings that don't need to be relieved slightly. If the end-gap is too tight, the ring ends can hammer the locator pin right out of the piston, with devastating results. Approx .004" per inch of bore size for the optimum ring end-gap clearance.

 Sticker not necessarily included