A Fantastic Value in the Power-Per-Dollar Department!

The Torkster 883-1200 conversion is a fantastic value in the power-per-dollar department, as it adds nearly 65% more power to the 883! The Torkster is not just a bore job to increase displacement, but a highly refined cylinder, head and engine management package that promotes big gains in power and torque.

The key is in the blueprinting of the head. After cleaning, new Step-Lock guides are hand-fit to new, high-flow stainless steel valves. Next, the bowl in the port is aligned to the center of the valve using a special form tool that promotes high velocity for optimum air to fuel atomization ratios. The result is increased fuel efficiency, and in layman’s terms, a big, fat, long torque curve!

The heads are delivered assembled with Viton® seals and a performance valve spring set; and after nearly 8 pounds of cast iron is removed from the cylinders*, they are precisely fitted with lightweight, reverse-dome forged pistons. To provide proper fuel and ignition curves, the factory ECM is replaced with the versatile ThunderMax ECM with AutoTune, supplied with maps that ensure quick and accurate automatic AFR tuning. A Zipper’s high flow air cleaner kit and complete top end gasket set is supplied. If you enjoy the feeling of strong power that really sits you back against the seat when you twist the grip, the Torkster kit is for you!

Zip Tip: 2004-up 883 Sportsters® have different primary and secondary gearing than the factory 1200’s do (final 4.07 [883] vs. 3.52 [1200]. We recommend lowering the final drive gear ratio when converting an 883 to 1200 with our kits.

These kits are available from any Zipper’s Performance Products dealer, or you can send your carefully packed parts directly to Zipper’s. The Torkster kit requires modification to your cylinders* and heads. Your original 883 parts are modified and returned to you, ready for installation. In-shop time is generally 1-2 weeks. Please pack your parts carefully!

Note for 2009 and Later 883 Owners – In 2009, H-D® made a change to the cylinder cast iron liner that no longer allows cylinder boring to 1200cc’s. New 1200 cylinders may be required for these applications – check your cylinders at the bottom spigot for an aluminum O.D. Below the base gasket surface.

All kits can be purchased whole or in any combination of desired components, please contact our sales department at 410-579-2828 for more details and pricing.



Zipper’s Job Order Sheet



This product is not for sale or use on pollution controlled vehicles.

Weight63 lbs
Emissions Compliant

Fuel / Air


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1 review for Zipper’s Torkster 883-1200 EFI XL® Sportster® Engine Kit

  1. 5 out of 5

    Pulls like a freight train! I acquired this bike from a friend who was quitting riding. After riding it I decided it was boring. With only 40hp is was really not that fun to ride. You had to wring the hell out of it to have any fun and it felt like it did not like that and was overstressed. I had Zippers do their magic. They installed the 1200cc Torkster kit. WOW. What an improvement. It is like a different bike. It is much smoother, power is everywhere. It does not matter if you are at 2000 rpm or 4000rpm it pulls like a freight train. Not scary fast like a hot rod, not peaky or temperamental, just clean power everywhere. It double the HP and TQ over stock with no negative side effects. I have had faster bike, but none ran an smooth clean or were as enjoyable to just go out and ride.

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