Stop cussing that early EFI system, just replace it!
Zipper’s has taken the popular ThunderMax® EFI electronics and merged it with a single-throat Delphi®-style throttle body (with the help of some specially made parts) and developed this full conversion kit for bikes with H-D’s earliest Magnetti-Marelli EFI systems. This kit allows you to retain the original wiring harness and gas tank, while upgrading to similar components used in the highly durable and reliable Deplhi®-based bikes of 2002-2005.
Gone is the idle stepper-motor and its funky linkages that caused wandering idle and hard starting! Gone are the limitations of the stock throttle body air flow and hard-to-find injectors! In its place are modern throttle body configurations available in multiple bore diameters allowing easy selection of performance injector sizes! This is THE KIT to use, especially for engines with performance modifications as our vast selection of ThunderMax base maps allows fast set-up and tune-in.
Instant starting! Consistent idle! Superb performance! It’s all here in this kit. The ThunderMax with its integrated AutoTune transforms this system to full closed-loop automatic air/fuel ratio correction, maintaining your custom tune no matter what the ambient conditions or elevation you choose to ride in! Includes detailed installation instructions and TMax Tuner software. Requires exhaust system equipped 18mm oxygen sensor bungs or modification to accept 18mm oxygen sensors.
You’ll fall in love with your bike all over again!
These kits are built to order with special parts for each application, Please contact a sales representative for lead time.
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.
SKU: 2319
Travis –
Great EFI upgrade! After 100K was time to freshen the ole girl up. Complete rebuild included this Thunder Max EFI with 51mm T-body, new case barrings, welded, balanced, and trued the crank, Stage 2 heads ported and polished by Salty (wow! great work and a great price you can find him on eBay), 98ci big bore kit and TW555 cams! She runs great (115hp/118tq) !
Mike Scherban (verified owner) –
I installed this kit myself on my 99 ultra. I previously had no cold idle and could not get better than 25mpg with the MM system. After installing the Zippers kit the bike ran way better. It pulls way harder than it used to. First run i went from 25mpg to 32…after i let it autotune i flashed that into the base map and reset it…then went from 32mpg to 37 mpg…best i have done is 40mpg….i am very impressed with this kit. It feels like a whole new bike.
Bryan Rudd –
simple and easy install…. bike runs great and pulls harder. i only have one complaint should send the breather bolts with the kit. if you are in my case with a stage one airfilter the bolts wont work…. other than that it woke up my bike. thank you for the great fuel system if i ha e to do it over on another bike i will any day of the week.
Marcus Laster –
Put this kit on my 01 RD king classic with sum light engine mods, The difference is night and day!!! Love it, would recommend it to anyone with the early magneti marelli system. Woke it up completely, best money I’ve spent on my machine. 2 thumbs up👍🏾👍🏾
Erick Kennard (verified owner) –
This kit is comprehensive, no guesswork, and gone are the days of messing with Magneti Marelli.
Instructions are easy to follow, and getting it set up is a breeze. Simply tell Zipper’s what your mods are, and they send you the ECU, pre-mapped with a base tune for your modifications.
Only change I’d make, is if there were conversion fuel lines available, something like the Goodridge lines to eliminate the weak HD factory lines.