ThunderMax® is an industry award winning, performance ECM designed specifically for EFI equipped Harley Davidson® motorcycles. This highly advanced, stand-alone tuning system utilizes proprietary AutoTune technology specificly designed to interface with wide-band oxygen sensors to automaticly adjust a wide range throttle positions and RPM ranges to deliver unmatched performance and driveability like no other product in the industry. ThunderMax® is made in the USA and comes 100% assembled, ready to install with no wire-cutting or splicing required. Simply replace the factory ECM and oxygen sensors, load a map, and enjoy your new ride!
Not legal for sale or use in California on any pollution controlled motor vehicle.
Not legal for sale or use on any EPA pollution controlled motor vehicle.
ThunderMax® is an industry award winning, performance ECM designed specifically for EFI equipped Harley Davidson® motorcycles. This highly advanced, stand-alone tuning system utilizes proprietary AutoTune technology specificly designed to interface with wide-band oxygen sensors to automaticly adjust a wide range throttle positions and RPM ranges to deliver unmatched performance and driveability like no other product in the industry. ThunderMax® is made in the USA and comes 100% assembled, ready to install with no wire-cutting or splicing required. Simply replace the factory ECM and oxygen sensors, load a map, and enjoy your new ride!
Not legal for sale or use in California on any pollution controlled motor vehicle.
Not legal for sale or use on any EPA pollution controlled motor vehicle.
We’ve taken the hassle of converting your late model belt driven H-D® to chain drive. Whether you’re interested in a different final drive ratio, added driveline strength or more clearance for a wider tire, these kits will make your life easier. Kits are available with durable, high wearing RK Pro O-Ring chains (best for street use) or RK's brutally strong, non-o-ring DR (Drag Race) chain.
*** Due to supply problems, 1991-1999 kits are only available with chrome steel or silver steel rear sprockets!!! 2000-2003 kits are only available with black steel rear sprockets. 2004 and alter kits are only available with chrome steel or silver steel rear sprockets**
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883 SPORTSTER® TORKSTER 883-1200 KITZipper’s Torkster 883-1200 kit Increases Your 883’s Horsepower output by 63% and its Torque by 72%! The key to this huge increase is Zipper’s High Velocity Stage II CNC headwork and carefully matched forged piston design. Your cylinders are decked on both ends, bored from 3” to 3.5” then honed on a state-of-the-art Sunnen SV-30. Heads receive Zipper's CNC porting to Stage II specs and are fitted with new Step Lock valve guides, stainless steel valves and upgraded valve springs. This combination promotes a great power curve, with torque topping 80 ft/lbs and HP over 75 - with factory camshafts! Supplied with a quality top end gasket set. Easy to install, fantastic results!Note regarding late 2009-up 883 cylinders: Since the 883 was introduced in 1986, H-D® used a thick iron insert in the casting that allowed the 3” bore 883 cylinder to be safely bored to 3.5” for 1200cc displacement. Mid-year 2009, this changed. Less cast iron was used, and the cylinders can no longer be bored to 1200 (see cutaway photo). If you can see aluminum on the outside of the cylinder spigot (arrow), your cylinders can not be bored to 1200 due to the step circled in red. We try to keep used, earlier versions in stock that we can use for these applications, but this is subject to availability and finish. Contact our sales department for availability. An exact color may not be available and you may need to paint to match your engine. H-D® sells color-matching spray paint you can use for this. We do not recommend powder coating as the heat required to cure the PC will alter the precision-bored finish of the cylinders.
*#517-912 Includes reconditioned ’04-‘E09 cylinders (see above note)This kit uses your factory head & cylinder* cores sent in for modification
Not legal for sale or use in California on any pollution controlled motor vehicle.
Not legal for sale or use on any EPA pollution controlled motor vehicle.
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Zipper’s Air Filter kits are designed to maximize available airflow and minimize intake turbulence at the entry point. We start with a fully machined, radius inlet billet backplate, and add special mounting and crankcase venting hardware that allows the installer to route breather venting internally or externally (purchase vent filter separately if external).
*1 Accepts stock '07-up oval Sportster® outer air cleaner cover (not included)
*2 Accepts EV BT round cover or accessory 8" covers (not included)
Not legal for sale or use in California on any pollution controlled motor vehicle.
Not legal for sale or use on any EPA pollution controlled motor vehicle.
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