{"product_id":"1200cc-piston-set-040-oversize","title":"1200cc Piston Set .040 Oversize","description":"\u003cp\u003eKeith Black flat top piston set is .040 oversize with a 8.9:1 compression ratio for 1988-up XL 1200cc Evolution models.\n\u003cbr\u003eThe Keith Black 390 hypereutectic alloy is cast in a permanent steel mold which makes it possible to build a light weight piston that makes more power and uses less fuel and lasts longer. Pistons are .040 oversize  for a 3.498 inch bore and has a 9:1 compression ratio. The low heat transfer of the alloy keeps the skirts cool so piston expansion is minimal. The combination of a low heat transfer piston alloy and high compression ring placement increases power and economy. The high ring placement alone reduces detonation and increases the top ring temperature.                                                                     **Note: Run engine at moderate speeds for at least 500 miles  avoiding excessive running in lower gears  in order to properly break-in new pistons and rings. \n\u003cbr\u003e Instructions: http:\/\/www.vtwinmfg.com\/Instructions\/MS\/KB Sym-Asym Piston Installation Guide.pdf\u003c\/p\u003e","brand":"Keith Black","offers":[{"title":"Default Title","offer_id":67622838763705,"sku":"11-2250","price":328.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0775\/0179\/2441\/files\/11-2250.jpg?v=1790864397","url":"https:\/\/www.thespeedshopusa.com\/fr\/products\/1200cc-piston-set-040-oversize","provider":"THE SPEED SHOP USA","version":"1.0","type":"link"}