S&S 128" M8 Big Bore Kit


The old saying is true.  There is no replacement for displacement!!!!  Already have a cammed M8 but want more fun?  This is the kit for you.  While the M8 114"/117" is a great improvement over previous engines, this bolt-on big bore kit takes your quest for fun to a whole new level.  Increasing your cylinder diameter to 4.25" and bumping the compression up to a completely streetable 11:1, this kit puts all the power you want at the twist of your wrist.  All of this is completed without the need to remove your motor from your bike or machine your cases - that means you can do the install in your garage.  The kit comes with pistons, new cylinders(no machining time), piston rings, wrist pins and clips, as well as new cylinder head and base gaskets.  Easy to follow instructions make this install a breeze.  The kit is available in three different finishes including black with highlights(stock), black granite(CVO), or black without highlights.

Fits:  All M8 motorcycles equipped with a 114"/117" from the factory

Note:  We highly recommend new cylinder head bolts.  Our https://fat-head-cycles.myshopify.com/admin/products/4725539209264 are a great choice or you can pick up part #10200303 from your local dealer.