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NOTICE: This very-limited-quantity special price below is only available with the discount code distributed on Black Friday only to Gearhead Newsletter subscribers.
Favored by those inspired by the old school cool, garage builders and riders of the nostalgic persuasion this transmission offers the worry-free convenience and reliability of a new BAKER Drivetrain product.
The introduction of the Knucklehead and the 4-speed in 1936 marked an epoch in the history of American motorcycles. Many consider the period of 1936-84 the holy grail of Harley fuckin Davidson. To carry on that legacy we developed the BAKER 4-speed, available with ratchet top or jockey top lids. The external architecture of our cast (A356-T6) 4-speed transmission case was modeled after factory cases to capture all the details and character of the original design. But we made many functional upgrades to address shortcomings of the original design like leaks, serviceability, and durability. The loose rollers on the maindrive gear were replaced with a radial ball bearing. The bronze bushings on the gearset were replaced with caged needle bearings. We added a provision, hidden in the back of the case, for an electronic speedo but retained the traditional worm gear speedo provision on the front of the case. The stock Fred Flintstone shift detent was replaced with a snot-slick linear ball bearing detent for that smooth ‘snick-pop’ shift quality you expect from us.
We manufacture three shift drums for the 4-speed; the FX & FL types with conventional shift patterns and the N1 style. The N1 drum takes the FX pattern and relocates neutral down below 1st for a N-1-2-3-4 pattern as an alternative to the standard 1-N-2-3-4 pattern. Great for foot clutch and performance applications.
Shift Lever Orientation:
The FL shift drum in a Jockey top cover is setup for a top pull (1936-46) or bottom pull (1947-65). The N1 shift drum in a Jockey top cover is setup for bottom pull only. The FL shift drum in a Ratchet top cover is bottom pull only. The FX and N1 shift drum in a Ratchet top cover is top pull only. For further information, please contact us through the website chat, email us at firstname.lastname@example.org, or call us Monday-Friday 8AM-7PM EST/EDT at 517-339-3835.
Case Finish Options
You have 3 different options for case finish on the 4-Speed.
Shift Drum Options
We manufacture 3 shift drums for the 4-speed; the FX & FL types with conventional shift patterns and N1 style.
The N1 drum takes the FX pattern and relocates neutral down below 1st for a N-1-2-3-4 pattern as an alternative to the standard 1-N-2-3-4 pattern. Great for foot clutch and performance applications.
Mainshaft lengthsWe manufacture 4 different length mainshafts for the 4-Speed; the 1936-64, 1965-69 (1st year of electric start), 1970-E84 and a 1970-E84 splined mainshaft for a modern clutch setup. To see our mordern Splined Shovel Clutch Click Here. BAKER does not make the late 84 (diaphragm clutch) style tapered mainshaft. All mainshafts are designed for caged needle bearings for 3rd gear, no more metal to metal like stock.
All BAKER 4-Speeds come standard with our Klassic Kicker Gears. 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.
Kicker Cover Options
We manufacture and sell 6 different kicker covers making the 4-Speed completely customizable. Kicker covers come in different finishes ranging from the standard chrome cover to the raw replica cover. To see the full line of kicker covers available Click Here. Depending on the choice of cover and finish, charges might apply.
4-speed gears and shafts are manufactured with 8620 steel. Vacuum carburized heat treat gives a case hardness of 58-62 Rockwell ‘C’. Gear tooth profiles are ground and finished with diamond tooling after heat treat to correct the tooth distortion that naturally occurs when you put a chunk of steel in a very hot furnace. Take off the shifter lid on our 4-speeds and turn the shafts; you will hear silence because the involute profiles are perfect. The designers of this transmission back in the '30s would be envious of the improvements we made to their design with modern manufacturing processes. We added lead-in helical ramps on the shift clutches to improve shift quality. All bronze bushings were replaced with modern low friction bearings.
Case Options & Provisions
The 4-Speed Transmission case was modeled after the factory 1936 and 1965 cases to capture all the details and character, but we made some modern improvements as well. Our 1936-64 case is a no ear case which utilizes the stock style speedo gear drive while our 1965-E84 is an ear case. Both cases have the option to use the speedo gear drive location but we also molded an electronic speedometer mounting boss to follow the ear on our 1965-E84 case only. By tucking the electronic speedometer provision mount by the ear you can conceal any modern components keeping your bike looking stock. The electronic speedometer would utilize a stock 1996-2006 speed sensor, PN 74437-96. Pending what type of electronic speedometer you use, an additional speedometer recalibration box might have to be purchased, BAKER PN 95E-56B.
Gear & Electronic Sensor Locations
|Recalibration Box 95E-56B|
Like the stock 1936-64 4-Speed the BAKER 1936-64 cases have an alignment track on the bottom of the case (in between the studs), tongue-and-groove for the transmission plate to prevent lateral movement of the transmission. Any forward and aft adjustment are done through the adjuster boss location for the primary chain. This type of setup ensures a positive alignment when running belt drive applications, where you don’t have an inner primary to lock the motor to the transmission.
All 4-Speed top covers have a hidden vent system which allows the transmission to breathe. Machined into the internal walls of the billet top cover, the breathing system flows through the ratchet cavity and out through the shift cover. Jockey top covers are vented out through the bottom side of the cover just below the neutral switch. Click Here to see all top cover choices and information.
Speedo Gear Drive
All BAKER 4-Speed gearsets come with the gear drive ring installed. Using the list below; pending the year and model of your motorcycle you will have to use the following gear drive unit OEM part number or equivalent for your speedometer to function correctly.
|Year||Speedometer Drive Ratio||OEM Drive Unit PN|
|1936-61||2:1 Ratio, 7 Tooth Drive Ring Gear||67130-36 (11 Tooth Drive Unit)|
|1962-67||1:1 Ratio, 4 Tooth Drive Ring Gear||67130-61 (13 Tooth Drive Unit)|
|1968-80||1:1 Ratio, 7 Tooth Drive Ring Gear||67130-69 (23 Tooth Drive Unit)|
1947-61 FL Models use a 2:1 Ratio Speedometer
1962-80 FL Models, 1971-72 FX Models and 1980-83 Models use a 1:1 Ratio Speedometer
BAKER 4-Speed part numbers and default speedometer gear drive configurations unless specified by customer that they are using the 1962-67 ratio as specified above.
|4-3664||4-speed, no ear case, 2:1 speedo drive||1936-64 FL & FX|
|4-6569||4-speed, 1:1 speedo drive||1965-69 FL & FX|
|4-7085||4-speed, 1:1 speedo drive||1970-E84 FL & FX|
|4-70E84||4-speed, 1:1 speedo, splined mainshaft||1970-E84 FL & FX, see note|
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
BAKER 4 Speed install instructions with exploded views : Click Here