top gear box 4-Speed Complete Transmission – BAKER Drivetrain

top gear box 4-Speed Complete Transmission – BAKER DrivetrainLIMITED AVAILABILITY! GIVE US A CALL AT 517 339 3835 TO ORDER YOUR 4 SPEED TRANSMISSION NOW! 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

LIMITED AVAILABILITY! GIVE US A CALL AT 517-339-3835 TO ORDER YOUR 4-SPEED TRANSMISSION NOW!

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 Complete Transmission. 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.

The sprocket/pulley is not included in the complete transmission assembly. For the acquisition of these components, kindly contact BAKER Drivetrain at 517-339-3835.

Features

• Vintage sand cast (A356-T6) design that holds true to the original 1936 through mid 1980’s.
• Hidden transmission vent designed into the Ratchet
• Billet steel machined and case-hardened shift systems (FL, FX and N1)  that rotate on Permaglide bushings for a smooth, repeatable shift each time; see technical section
• BAKER Classic Kicker Gears come standard
• BAKER Offset Kick Arm comes standard
• Modern 4 speed gearset made out of 8620 gear steel
• Gears ride on needle bearings, not bronze bushings
• Vintage cast kicker cover with traditional 1 piece release rod and BAKER Heavy Duty throwout bearing
• Direct bolt-in on most models; see instructions for 65-69 fitment (ear case)
• 5 Year limited warranty

Fitment

• 1936 to 1984 Knucklehead, Panhead or Shovelhead
• 1936 to 1964 tapered mainshaft
• 1965 to 1969 tapered mainshaft
• 1970 to E1984 tapered or splined mainshaft 

Shift System:

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 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 [email protected], or call us at 517-339-3835.

Part Number

Detail

Case Finish Options

You have 2 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 lengths

Kicker Gears

All BAKER 4-Speeds come standard with our Classic 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

Kicker covers come in different finishes ranging from the standard chrome cover to the raw replica cover. 

The offset kick arm comes standard. 

Gearset

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.   Any factor Harley electronic speedometer will work with the transmission. We recommend using the Dakota Digital Billet sensor.  Depending on what type of electronic speedometer you use, an additional speedometer recalibration box might have to be purchased, BAKER PN 95E-56B.

Alignment Track

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 adjustments 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. 

Top Covers

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. 

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.

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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 the customer that they are using the 1962-67 ratio as specified above.

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 Fluid Capacity Dry: 22-24fl-oz
• BAKER 4-Speed Fluid Capacity Wet: 18-22fl-oz

Installation Instructions

BAKER 4 Speed install instructions with exploded views: Click Here