ENGINE SECTION RED PART NUMBERS INDICATE NEW PARTS 6-43 1 2 3 4 5 6 7 8 9 10 11 CONTENTS ELECTRICAL FRAME FRONT END CONTROL WHEEL ENGINE DRIVE TRAIN FUEL EXHAUST GENERAL REFERENCE • Wiseco Big Bore pistons are forged from hi-silicon aluminum alloy for superior strength and dependability. • The unique piston shape allows tight piston to wall clearances for quieter operation. • Grooves are machined around the top ring lands to reduce detonation and improve the sealing power of the top ring. • Designed for stock stroke flywheels only. • All wrist pin holes are ream fit for a perfect geometrical surface. • Enlarged valve pockets provide the clearance for larger valves and high lift cams but must be checked. • Includes Instructions and clearance recommendations. • All Piston Kits include Cometic brand gasket sets. Note: Hastings replacement rings are for one piston only. BIG BORE PISTON KITS WITH GASKETS FOR TWIN CAM Compression Bore Piston Kit Replacement Replacement Piston Model & Year Ratio Size Part # Ring Set Lock Ring Pair Style Twin Cam 1999/Later 9:1 Standard 62236 63021 65103 1550cc (95ci) +.010” O.S. 62238 63023 65103 10.5:1 Standard 62233 63021 65103 Big Bore Twin Cam Pistons & Big Bore Kit Model & Year Description Bore Size Part # Ironhead Sportster 1972/1985 1000cc (61CI) STD Bore 62402 Note: It is not recommended to bore STD Bore = 3.188” +.010” 62404 1972/Early 1973 models more than +.030” 8.2:1 compression ratio +.020” 62405 Dome top pistons +.030” 62406 +.040” 62407 Evolution Sportster 1988/2003 1200cc (74CI) +.010” 62274 STD Bore = 3.498” +.020” 62275 9:1 Compression ratio +.030” 62276 Flat top pistons 1200cc (74CI) +.010” 62431 STD Bore = 3.498” +.020” 62432 8.9:1 Compression ratio Flat top pistons with valve pockets cut .060” deeper for use with shaved heads & high lift cams Evolution Sportster 1986/Later 1200cc (74CI) STD Bore 62290 STD Bore = 3.498” +.005” 62291 883cc to 1200cc 10:1 Compression ratio +.010” ----- Overbore conversion Dish top pistons that do not require head modification PERFORMANCE PISTON KITS FOR SPORTSTER • Spawned from this successful manufacturer’s line of automotive pistons. • Lightweight permanent mold cast pistons. • Manufactured from Hypereutectic 390 Alloy, contain 16-18% silicon, and heat treated to T6 specifications producing a stronger than stock piston. • Special alloy composition keeps heat confined to the combustion chamber and reduces heat transfer to the piston itself, producing a cooler running piston. • Piston expansion is reduced by as much as 20% over conventional pistons. • Less piston rock, better ring support, more durability and better retained compression for maximum power. • The key feature to these pistons is the accumulator groove between the tip and second ring which averages the normal pressure between the first and second ring, keeping the pressure low enough to prevent lifting of the top ring while maintaining preload on the second (oil scraping) ring. • Each set of pistons includes wrist pins, spiral locks, engine assembly lube, and Hastings Moly rings. • Order 65199 for replacement wrist pin spiral lock (sold each). • Wrist pins measure .792” OD. • See page 6-45 for replacement rings.
RkJQdWJsaXNoZXIy MzYzNTI=