Mary Shelley published the novel ‘Frankenstein’ when she was 19 years old in 1818. Her brilliant story has withstood the test of time with many subsequent novels based on her work and many interesting movies. According to the inner circle of the BAKER opium den, the 1936-based Harley 4-speed kicker is the mechanical equivalent of Ms. Shelley’s literary masterpiece. So we got inspired by her and went back to the R&D lab and pieced together something for Evos and 1st generation Twin Cams. Effectively, we combined a 4-speed kicker with a BAKER 6-speed that fits into the 5-speed cases used from 1990-2006.
– Billet 6061-T6 bearing door
– Hard chrome plated shift forks
– Diamond cut OD6 Gearset
– 500 RPM reduction in cruising speeds on highway in 6th gear
– Doweled trap door for positive kicker cover alignment (ONLY with BAKER Kicker Covers)
– Redundant neutral shift system
– 5 Year limited warranty
Made out of Billet 6061-T6 the Frankentranny bearing door is about 1 3/8″ wider then a stock 5-Speed . The door is wider in order to contain the 6th gear and all of the kicker gear components used in a 4-Speed application. The beehive spring is contained within the door riding on a ball mill track, the kicker gear stops are machined into the internal profile of the door for strength. In looking at the sectioned view you can see we didn’t leave any room to waste.
Our 6 Speed shift system with roller detent guarantees smooth shifts every time and our redundant neutral ensures that finding neutral is a easy chore. We mount a plunger detent on the left side pillow block and cut a plunger track into the shift drum itself. The plunger follows this track during operation (shifting) and when shifting into neutral pops into a pocket. This system lets you feel that you’re shifting into neutral. No more guessing. Shift drum features more aggressive timing on the fork groove profiles and is case hardened to 58 Rockwell for wear resistance and crisp shifts. We built our reputation on smooth shifting 6-speed transmissions; our drum designs benefit from the engineering lessons learned.
The Frankentranny utilizes the OD6 gearset. Made out of 8620 steel, gears are shaper cut before heat treat then precision ground with diamond coated tooling after heat treat (58-62 Rockwell ‘C’). This extra steps ensures not only a quieter gear pair, but enables much tighter backlash control. This tighter control on the gears yield a silent operation.
The Frankentranny comes in a standard ‘2.94’, optional ‘3.24’ or R-Ratio ‘2.82’ configuration. A way to physically tell which ratio you have is pretty common knowledge here at BAKER, but if you would like to know look at the 1st gear pair on the gearset. Our standard 2.94 1st gear will not have a notch on the 1st countershaft gear, our (stock) 3.24 1st gear will have a single notch around the center of the 1st countershaft gear and our 2.82 (R-Ratio) 1st gear will have 2 notches around the 1st gear countershaft. Use the image on the far right for reference. This is very important to know if you need any replacement parts or components.
Our investment cast shift forks are made out of 4140 then dipped in a hard chrome plate bath for wear resistance, also designed with oil reliefs to ensure proper lubrication and wear resistance on fork blades and shift dogs.
Available No Cost Options
– Standard Shift Drum (1-N-2-3-4-5-6)
– N1 Shift Drum (N-1-2-3-4-5-6)
– Ear or no starter ear case (for complete builds only)
The Frankentranny comes in a standard, optional or R-Ratio configurations
|1st Gear||2.94 / Optional 3.24|
Builder’s Kit Part Numbers
All Part Numbers Listed Are Standard 2.94 Gear Ratios
|FT106L||Frankentranny Builder’s Kit||1990-97 Big Twin – All Models|
|FT106SL||Frankentranny Builder’s Kit||1998-99 Softail1998-00 FLT-FLH & Dyna|
|FT106P||Frankentranny Builder’s Kit||2001-05 Dyna2001-06 FLT-FLH2000-06 Softail|
Builder Kit Notes
– EFI models require carb retrofit and cam based ignition
– FL Models from 1993-Later require a BAKER FF oil spout See Recommended Upgrades
– For N1 shift system add suffix ‘N1′ to the part number; example FT106L-N1
– The Frankentranny is available with a 3.24 optional 1st gear ratio . Change the middle numeral ‘0’ to a ‘1’. example: FT116SL
– For R-Ratio gears change the middle number ’0′ to ’21′; example FT1216SL
– Some exhaust systems may not be compatible with the Frankentranny Kit due to extended mainshaft and bearing door length.
-We started providing install DVD’s with every builder’s kit starting in October 2012. At approximately 3:25 of the OD6 portion of the DVD, Bert talks about modifying the shifter pawl. This modification is related to the stock shifter pawl lever assembly (H-D PN 34972-02B) and the use of BAKER 5-6QSN & 5-6QLN shift drums. We now provide a shift drum BAKER PN 124-0D6, which supercedes the 5-6QSN, 5-6QLN Shift, 5-6QEN, 5-6QFN & 5-6QGN shift drums, that requires no shimming and works with BAKER shifter pawl 555-56C or 555-56L (depending on year or motorcycle) which we include in kits and on all BAKER complete builder’s kits. We do not sell any kits, shift drums or transmissions that require any shifter pawl with BAKER marked on it, that needs to be ground or modified anyway. Any questions, please call us at 877-640-2004.
– Kit does not include, kicker cover or components. See Recommended Upgrades
Complete Build Part Numbers
All Part Numbers Listed Are Standard 2.94 Gear Ratios
|K701*||Frankentranny Complete w/Standard Cover||1990-99 Softail|
|K701*-FF||Frankentranny Complete w/FF Cover||1990-99 Softail|
Complete Build Notes
– For N1 shift system add suffix ‘N1′ to the part number; example K701P-N1
– EFI models require carb and cam based ignition
– The Frankentranny is available with a 3.24 optional 1st gear ratio . Change the middle numeral ‘0’ to a ‘1’. example: K711*
– For R-Ratio gears change the middle number ’0′ to ’21′; example K7211*
Complete Build Case Finish Options
Replace the “*” in the part number to a ‘P’ for Polished, ‘R’ for Raw or ‘B’ for Wrinkle Black ; example: 701B
Ear or No Ear
You get the look of an old bobber with the Frankentranny, but you also have the option to use a modern starter. Start with a push of a button or kick start. If you would like to keep things simple, we can remove the starter ear on the case. Start your bike the old fashioned way, by kick only.
For a No Ear Case add suffix ‘S’ to the end of the part number; example K701P-N1-S
The BAKER Softail case design had all leak potentials in mind during the design. We added stud pads to the inside of the case so that the thread holes for the transmission studs were blind holes, NOT through holes like some aftermarket brands. Looking at the image on the right you can see the difference.
All complete Frankentranny’s come with our Klassic Kicker Gears standard. Made out of 1018 HR Steel, tumble finished to around a 20 micro and heat treated to 50-55 RC; these gears roll smooth as glass.
A Speedometer recalibration unit is required for electric speed sensor applications; PN 95E-56A. The sensor is going to be plugged into the bearing door and NOT the case. Complete builds will not have a speedo sensor hole on the case, but if you are doing a builder’s kit the case will hole will have to be plugged off. A sensor plug comes in the kit which is usually installed on the bearing door for safe keeping.
Ignition Retrofit Alternatives
Starting in 1999 with the first Twin Cam engines, Harley started using a flywheel-based trigger for the ignition. This style ignition requires the flywheel (aka crankshaft) to turn over 3 or 4 times for it to ‘find itself’ before it starts sparking. 3 or 4 rotations of the flywheel may not sound like much while you’re taking a shit right now and reading this, but it’s almost humanly impossible. Cam-based ignitions spark spark at less than one flywheel revolution and it lights off the first time it hits TDC.
If you install one of our Frankentranny kits on a Twin Cam you must covert the ignition to a cam-based unit like the ones shown below. Also EFI models will have to be converted to a carb setup.
Any information regarding the ignition units please visit the company websites listed below by clicking on the link.
|5011||Gates Performance Kit||Gates Performance Website|
|T-5||Morris Magneto Kit||Morris Magneto Website|
|3757||Vulcan Cover Kit – 1||Vulcan Engineering Website|
|3886||Vulcan Cover Kit – 2||Vulcan Engineering Website|
|4365||Vulcan Cover Kit – 3||Vulcan Engineering Website|
– Kicker Covers
– Kicker Arms / Pedal
– Klassic Kicker Gears
– Inner Primary High Torque Bearing Kit
– SP9: Street Performance 9 Plate Clutch
– King Kong Clutch
– Formed Oil Spout (For 1993-Later FLT/FLH Models Only)
Click on any of the images below to learn more
Recommended Fluid / Level
Picking the right transmission fluid ensures the life and durability of your transmission, that’s why BAKER recommends a fully synthetic GL-5 rated gear weight oil of 75W-140. If a GL-5 rated gear lube is not available, these commonly carried viscosities (weights) will work 75W-90, 75W-140 and 85W-140. BAKER does not recommend the use of Syn3 (20W-50). For Bert’s article on ‘Oil & Spiders’ Click Here
Frankentranny Fluid Capacity Dry: 22-24fl-oz
Frankentranny Fluid Capacity Wet: 18-22fl-oz
Frankentranny installation instructions with exploded views: Click Here
We started providing install DVD’s with every builder’s kit starting in October 2012. At approximately 3:25 of the OD6 portion of the DVD, Bert talks about modifying the shifter pawl. This modification is related to the stock shifter pawl lever assembly (H-D PN 34972-02B) and the use of BAKER 5-6QSN & 5-6QLN shift drums. We now provide a shift drum BAKER PN 124-0D6, which supercedes the 5-6QSN, 5-6QLN Shift, 5-6QEN, 5-6QFN & 5-6QGN shift drums, that requires no shimming and works with BAKER shifter pawl 555-56C or 555-56L (depending on year or motorcycle) which we include in kits and on all BAKER complete builder’s kits. We do not sell any kits, shift drums or transmissions that require any shifter pawl with BAKER marked on it, that needs to be ground or modified anyway. Any questions, please call us at 877-640-2004.
1st Gear Design Change
1st Gear Change Addendum-March 2012: Click Here
I want to thank you for your time and advice when I stopped by your shop a few weeks ago to inquire about a Frankentranny for my ’93’ Softail.
I took your advice and went to see Dan at Diggers Speed Shop in Kalamazoo. Dan, Lance, Jerry and the guys were very easy to talk to and very enthusiastic about taking on the job. Ever since I first saw The Frankentranny in a cycle magazine I’ve wanted to put one on my bike. Diggers was the first shop that didn’t try to talk me out of it, in favor of a less expensive alternative.
The guys at Diggers did a great job for me. Do to the age and miles on my old Softail, the job quickly “snowballed,” as we all suspected that it would. Dan and Jerry stayed right on top of it though and got me out the door with exactly what I was hoping for, at a very fair price.
I can’t tell you how much it means to me to have a Michigan made, Baker transmission on my bike. Getting to meet the guys at Diggers was really icing on the cake, I will recommend Baker and Diggers to anyone who asks.