BOLD MAGENTA part numbers are new for 2026 PISTON & PISTON KITS PARTS-UNLIMITED.COM OFFROAD | 2026 PISTON & PISTON KITS 1421 HIGH-PERFORMANCE PISTONS continued on next page. FITS MODEL BORE (MM) X STROKE (MM) DISPL. (CC) BORE SIZE (MM) OVER SIZES (MM) PK KIT PART # PISTON PART # REPL. RING SET PART # REPL. CIRCLIPS PART # REPL. WRIST PIN PART # TOP-END BEARING PART # YAMAHA 2-STROKE (CONT) YZ250 83-87 68 246.8 68 STD - 560M06800 2677CD CW18 - B1014 Power Valve must be modified for 0.040 and larger. Pro-Lite. x 68.25 0.25 - - 2687CD 68 68.5 0.5 - 560M06850 2697CD 69 1.0 - 560M06900 2717CD 69.5 1.5 - 560M06950 2736CD 70 2.0 - - 2756CD YZ250 83-87 68 246.8 68 STD - 560M06800 2677CD CW18 - B1014 Power Valve must be modified for 0.040 and larger. Pro-Lite. x 68.25 0.25 - - 2687CD 68 68.5 0.5 - 560M06850 2697CD 69 1.0 - 560M06900 2717CD 69.5 1.5 - 560M06950 2736CD 70 2.0 - - 2756CD YZ250 92-98 68 246.8 68 STD - - - CW18 S-508 B1014 Racer’s Choice. x 250cc Single ring. 68 YZ250 99-01 66.4 249 66.4 STD 0903-0921 804M06640 2614CD CW18 S-508 B1003 Ceramic Composite - Cylinder sleeving or replating required for oversizes. Pro-Lite. x 67 0.6 - 0910-1244 2638CD 72 67.5 1.1 - 0910-1245 2658CD 68.5 2.1 - 0910-0207 2697CD YZ250 02-24,YZ250X 16-24 66.4 249 66.4 STD 0903-0308 804M06640 2614CD CW18 S-508 B1003 Ceramic Composite - Cylinder sleeving or replating required for oversizes. Pro-Lite. x 67 0.6 - 0910-1244 2638CD 72 67.5 1.1 - 0910-1245 2658CD 68.5 2.1 - 0910-0207 2697CD YZ250 02-24,YZ250X 16-24 66.4 249.3 66.4 STD 0903-0929 0910-0367 0912-0106 CW18 S-508 B1003 Racer’s Choice 250cc; Single ring. x Electra Coated.ArmorGlide skirt coated. 72 DT400 75-78, MX400 75-78 85 397 85 STD - - 3347TD CW18 S-277 B1003 x 85.5 0.5 - 232M08550 - 70 86 1.0 - 232M08600 3386TD 86.5 1.5 - - 3405TD 87 2.0 - - 3425TD IT/YZ400 76-78 85 397 85 STD - - 3347TD CW18 S-277 B1003 x 85.5 0.5 - 394M08550 - 70 86 1.0 - - 3386TD 86.5 1.5 - 394M08650 3405TD 87 2.0 - - 3425TD IT465 81-82,YZ465 80-81 85 465 85 STD - - 3347TD CW18 S-277 B1014 X 85.5 0.5 - 451M08550 - 82 86 1.0 - - 3386TD 86.5 1.5 - 451M08650 3405TD 87 2.0 - - 3425TD IT490 83-84,YZ490 82-83 87 487 87 STD - 478M08700 3425TD CW18 S-277 B1014 x 87.5 0.5 - 478M08750 - 82 88 1.0 - 478M08800 - 88.5 1.5 - - - 89 2.0 - - 3504TD YZ490 84-90 87 487 87 STD - - 3425TD CW18 S-277 B1014 WR500 91-93 x 87.5 0.5 - - - Pro-Lite. 82 88 1.0 - 546M08800 - 88.5 1.5 - 546M08850 - 89 2.0 - 546M08900 3504TD YAMAHA 4-STROKE TT-R90E 03-07 47 90 47 STD - 0910-0368 0912-0112 CW13 0913-0005 - 11:1 High-Compression x 92 47.5 0.5 - 0910-0369 0912-0113 Cylinder boring required for oversizes. 51.8 94 48 1.0 - - 0912-0114 110 52 .0 5.0 - - 0912-0111 TT-R125/L (all) 00-23 54 123.7 54 STD 0903-0742 4752M05400 - CW15 - - 11:1 Compression x 54.5 0.5 0903-0740 4752M05450 - 54 55 1.0 0903-0741 4752M05500 - TT-R250 99-06 73 249 73 STD - - 2874XC CW18 - - 10.5:1 Compression x 73.5 0.5 - 4689M07350 2894XC 59.6 74 1.0 - 4689M07400 2913XC WR/YZ250F 01-04 77 249 77 STD - 0910-0573 - CW16 0913-0008 - 12.7:1 Compression (0903-0554/0910-0573) x 262 79 2.0 - - 3110XG 13.2:1 Compression (0910-0574) 53.6 WR250F 01-13,YZ250F 01-11 77 290 83 6 - 0910-2936 3268XG CW16 0913-0008 - 12.5:1 Compression x 290cc Big Bore. 53.6 ArmorGlide skirt coated. HIGH-PERFORMANCE PISTONS (CONT)
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