S&S Cycle 1250cc Conversion Kit To Turn A Harley Sportster Into A Smoking Sporty


The Harley Sportster being so popular again, you could imagine that S&S Cycle would not take long would to release a conversion kit to add the adjective “smoking” to the Sporty name.

1250 cc is more than double the horsepower of a factory 883 Sportster! The kit is the largest big bore kit S&S offers for 1986-’14 Harley-Davidson® Sportster® models that can be bolted directly into stock crankcases. It includes 3-9/16” bore pistons, cylinders, and gaskets.

Needless to say the new S&S 1250cc conversion kit will appeal to the rider who wants to get the most from his or her bike, so S&S also recommends the S&S 600 cams and S&S CNC ported heads  to complete the package. Make the most of that displacement!

1250ccterThe Dynojet® 250i chassis dynamometer shows what a potent package the S&S® 1250cc kit for Harley-Davidson® Sportster® models can be. This chart compares a stock 2009 883cc engine before and after the 1250cc kit was installed. Over twice the horsepower! In addition to the 1250cc kit with 5.5cc pop-up dome forged pistons, the test bike was equipped S&S slip-on mufflers, stock EFI throttle body with an S&S tuned induction system, S&S 600 cams, and stock cylinder heads CNC ported by S&S. (Note: Not recommended for engines with stock 883 heads, but works great with stock 1200 heads and 883 or 1200 heads CNC ported by S&S)

Choose from silver or wrinkle black powder coat finish that matches the stock finish on late model engines. Also, these kits are available with flat topped or 5.5cc pop-up forged pistons for a choice of compression ratios. Flat topped pistons yield 10.3:1 with stock 1200cc heads or S&S CNC ported heads. The pop-up pistons deliver 11.2:1.

If you’re looking for the largest bolt-on kit available, this is it! The S&S 1250cc kit delivers great performance at an affordable price. $989.95.



7 Responses to “S&S Cycle 1250cc Conversion Kit To Turn A Harley Sportster Into A Smoking Sporty”

  1. 1 Rod Feb 26th, 2014 at 9:37 am

    And to your insurance company it is still an 883 for setting the rates. Sweet..

  2. 2 BobS Feb 26th, 2014 at 12:21 pm


  3. 3 Mikira Feb 26th, 2014 at 2:08 pm

    What great bolt on performance? The figures are not with only the cylinder kit, how much is the whole package for the near 100hp curve?

  4. 4 Blackmax Feb 26th, 2014 at 4:52 pm

    Nice! Nobody does it better than S&S
    Rock Solid !

  5. 5 Terence Tory Feb 26th, 2014 at 6:09 pm

    How long will a late model XL crankshaft handle this kind of power increase and high revs? Not long,I say.

  6. 6 Burly Brand Feb 27th, 2014 at 12:45 am

    Can we get a six pack of these?

  7. 7 Sportster Mike Feb 27th, 2014 at 5:36 am

    Yes, looks fab.. and yes you need to do the heads as well and the cam while you are at it

    I was saving up for the Hammer Performance package – which have the big fin cylinders – they don’t seem to have a problem with 100hp power…

    Do these cylinders have the big fins? can’t seem to find on the S&S website…

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Cyril Huze