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NRHS Sportster 883 to 1250 Upgrade Conversion Kit

Regular Price: 699.95

Special Price 599.95

Availability: Out of stock
Item #: DK-NRHS-1250
Manufacturer: NRHS

NRHS Sportster 883 to 1250 Upgrade Conversion Kit  for Harley Davidson DK Custom Products Iron lined cylinders forged pistons increased power


883 to 1250cc

Conversion Kit

(also works for 1200 to 1250 Upgrade)


1986 and Up Sportsters



  • Set of Premium Forged Hurricane Reverse-dome conversion pistons
  • 3-916 bore = 10:1 Compression ratio in stock 883 heads
  • If you're upgrading your 1200 to 1250 You will receive 10.5:1 Pistons*
  • Set of NRHS iron lined Aluminum cylinders
  • Rings, pins, lock and circlips
  • Cometic EST head/base gasket set
  • NRHS will gap your rings and pre-install your assembled pistons into pre-lubed cylinders if requested
  • Your Cylinder choice of silver, black or black with highlighted fins
  • Everything you need to bolt on, no case boring required



Check out the video below.  This is an 883 low with this NRHS 1250 Conversion installed.  Stock Heads.  The wheelies are all done with roll-on power only, NO clutch used.  Just twisting the throttle.


The famous NRHS 1250 kit takes your 883 to the largest displacement that will fit into the stock cases.  No hassle and expense of case boring.  It bolts right up.

Your choice of cylinder colors:  silver, black or black-highlighted.

The iron-lined aluminum construction of the cylinders offers excellent heat dissipation, together with structural integrity and ring seal of a thick ductile iron liner that wears much less than the factory cylinders.

Also include are the NRHS Premium Forged Pistons, Total Seal Rings, pins, locks, circlips, and Cometic Head & Base gaskets.

This kit works with all EVO Sportsters 1986 and up, including the EFI models.  There are slight differences in gaskets and fins, so please use the drop down below to let us know what Model Year you are ordering for.

Rejetting/upgrade to an adjustable ignition module for carbed engines and  for EFI engines  a tuner is needed with this 1250 Conversion.

*If you are converting your 1200 to 1250, and have or are adding more aggressive than stock cams, you will recieve 10.5:1 Pistons that work well with the 1200 heads, for even more power. Make sure to let us know it is a 1200 to 1250 Conversion, and if you are keeping the stock cams or using aftermarket cams, in the drop down below.


If your bike is 2 years old or has more than 4,000 miles, you should consider upgrading to a full Cometic top end gasket kit.  This kit includes all rocker box, head, base, pushrod, intake and exhaust gaskets. 

Note:  All 1250 Conversions use the 2003 and older style cylinders.  They bolt up just like the newer cylinders but the fins are slightly smaller.  This does not cause any extra heat and most cannot tell the difference when installed.  Look at the pictures below.

Check out the Dyno Chart above. Just bolting on this upgrade kit will almost DOUBLE Your Power. 

These typically ship 2-4 days after order is placed.

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