BAKER Drivetrain

The love affair with classic motorcycles will never stop and there’s nothing like putting authentic, vintage styled components on your nostalgic bike. That’s why BAKER has taken the time to reinvent the 4-speed transmission. BAKER 4-speeds are intended as stock replacements and work as bolt-in transmission on most models, whether you’re running a stock closed type primary or open belt drive. While looking like the original patterns on the outside, they are packed inside with improvements and extras: Gearset is made out of high grade 8620 steel, Gears ride on needle bearings, High tensile cast aluminum (A356-T6) transmission case, designed for roller ball bearing main drive gear, With 1979-83 Big Twin 5 speed sprocket, Ratchet top cover with linear detent system for smooth reliable shifting, Billet steel machined and case hardened shift drum rides on two Permaglide bushings, With BAKER Klassic kicker gears, Vintage style cast kicker cover, Includes 1939-75 style throw-out bearing and release rod, Gear ratios: 1st - 2.50:1 2nd - 1.70:1 3rd - 1.25:1 4th - 1:1 The shift drums on FL and Fx style versions are different, while the shift pattern is 1N234 for both. So, on FL style ratchets the shifter lever points downward, while on FX style ratchets the lever points upward. Can be equipped alternatively with 1:1 ratio mechanical speedo drive or with sensor for electronic speedometers.

Convert your old rumblin’ mill into a purring interstate mile eater. These transmissions are replacements for stock 4-speed units. They bolt directly into your stock frame and your stock 4-speed primary and dry clutch fit right up. The BAKER 6 into 4 has a 1:1 fifth gear and a 0.86:1 overdrive sixth gear for a 500 rpm reduction in cruising rpm on the highway. There is no provision for mechanical speedo drive, but the case accepts a sensor. The sensor-triggering gear has 37 teeth. Gear ratios: 1st - 2.94:1 2nd - 2.21:1 3rd - 1.60:1 4th - 1:1.23 5th - 1:1 6th - 1:0.86

This is the original 6-speed design that revolutionized the American V-Twin industry. Yet, it‘s still one of the best overdrive 6-speeds built to this day...hands down. The BAKER OD6 is built to comfortably handle the power from today's big-inch motors and has the gear ratios to suit your fast highway cruising needs. Example: in 6th gear at 70 mph, the engine revs 2720 rpm compared to 3170 rpm with a regular 5-speed transmission (calculated data based on a 24/37 primary, a 32/70 secondary, and a 25” rear tire). Gear ratios: 1st - 2.94:1 2nd - 2.21:1 3rd - 1.60:1 4th - 1.23:1 5th - 1:1 6th - 0.86:1

A super strong kicker arm which has a twice as thick cross section compared to stock counterparts. Features a 45 mm offset design to clear most exhaust systems.

A super strong kicker arm which has a twice as thick cross section compared to stock counterparts. Since this kicker arm is straight, make sure it'll clear your exhaust before ordering.

This kicker pedal is cast from bronze and reinforced throughout. It features a heat treated spindle with 5/8” diameter (stock = 1/2”) to prevent breaking.

The BAKER Shift Fork Kits include all three forks and are a direct replacement for the standard OEM 5-speed transmission forks but with much needed improvements over the stock design. Cross section is three times thicker than stock.

BAKER improved the shape of the splines, to prevent stripping, and a thicker truss style cross section offers a stronger overall design.

The stock ratchet pawl used from 1980 to 2000 utilized a scissor spring that was well known for breaking. Each time an upshift or downshift is made the pawl spring is cycled. After many cycles, the spring leg breaks. The unfortunate side effect of this failure is the broken spring leg going through the transmission gears and destroying the transmission. The BAKER ratchet pawl utilizes a more substantial, rectangular cross-section spring like the 21st century Big Twins. Other improvements include: Lever ‘beak’ for overshift protection, Pawl shaft lever splines are hobbed on a gear cutter just like our gears for high strength,

Have you ever heard of a 5-speed transmission dipstick breaking off and working its way into the transmission with disastrous results? Ask any seasoned technician; he’s seen one. Over time, the low frequency firing pulses of the American V-twin make the stock zinc die-cast dipstick break off and now you know the rest of the story. Bigger motors make this situation even worse. BAKER redesigned the dipstick with the largest radius possible between the stalk and the head. This radius stiffens the dipstick and increases its natural frequency.

If you need to cap off the speedo sensor hole for whatever reason, you need this plug. Some other companies do this with a steel plate and a gasket, just like old 4-speeds. BAKER plugs are machined from 6061-T6 and include a no-leak o-ring and a chrome button head screw for a clean look.

Over time and miles with dirt and grit, the stock 33344-94 spacer is too soft and it gets gouged by the seal that rides against it. As the spacer gets gouged, the seal relaxes. When the seal relaxes, the leaks begin. The BAKER sprocket spacer is a direct replacement for the stock spacer except it is case hardened steel that has a Rockwell ‘C’ hardness of 55. No more gouging, no more leaks.

When using aftermarket clutches like Barnett Scorpion and Rivera Pro-Clutch with 7/16”-20 adjusters you require this special adjuster screw and locknut.

When using stock clutches you require this special adjuster screw.

Performance transmission top assemblies by the US company BAKER. These stock replacement Ratchet Tops are available in your choice of an FL or FX shift system, with the FL systems set up as bottom pull and FX systems set up for top pull. All tops feature billet steel machined and case hardened shift systems that rotate on Permaglide bushings and a linear detent system for a smooth repeatable shift each time. The lids are cut out of Aircraft grade 6061-T6 billet aluminum. A hidden top cover vent design eliminates clogged vent screws. The shifter pawl backing plate is hard anodized for wear resistance.

The N1 shifter drum by Baker converts a standard FL shifter cover (ratchet top 1952-1979) from the stock 1N234 shift sequence to 4321N (Neutral all the way up). This is very helpful when drag racing or at traffic light "encounters", because you just stomp down on the shift lever from Neutral to upshift. Jockey shifters and suicide clutch users also benefit from this set-up because the "all the way forward" neutral makes quick stops safer.

The OEM 34091-85 inner bearing race has been used on Big Twins since 1985. The OEM 9135 roller bearing rides on this race. By design, this race press-fits onto the transmission mainshaft. This system works fine for stock motors, however, 100 HP+ motors will make this bearing walk on the mainshaft. If it walks towards the tranny, it will damage the maindrive gear seal and cause a transmission oil leak. If it walks towards the clutch, it will cause a primary oil leak. This ball bearing kit eliminates this condition.

This kicker cover is milled from solid aluminium, which guarantees high stability. Cracks, as they occur more frequently in cast iron covers, are therefore almost excluded. It features an integrated Evo type ramp and ball release mechanism for smooth and easy clutch actuation and is designed to work with 1987→ clutch cables. The clutch release lever and clutch cable bracket are omitted. Kicker shaft, high-strength BAKER Klassic starter gear are pre-assembled.

High performance kicker cover which features a show polished BAKER "Function Formed" design and which is machined from Aircraft Grade 6061 Billet aluminum for strength and increased part life. Included with this cover is a pre-installed 1-piece kicker shaft bushing plus smooth and strong BAKER Klassic kicker gears.

The time honored 1936 design, re-engineered by the US company BAKER. These gears are CNC-machined and heat treated, which results in smooth rolling and high wear resistance. No more broken-off stop pegs and deformed kick-back plates. These are the last kicker gears you will buy for a long, long time. Each kit consists of five pieces and fits all 1936-85 four speed transmissions.

In the original and many aftermarket kicker covers, one kicker shaft bushing is pressed in from both the outside and another one from the inside, with the seal (a cork ring with a rectangular cross-section or a thin O-ring) placed between them. BAKER has simplified and thus improved the design in its kicker covers. There is a 2” long bronze bushing, with the seal sitting on the outside under the thrust washer. This ensures that the bushing is lubricated along its entire length, whereas in the original setup the outer bushing always suffers from a lack of oil.

6-speed transmission »6 in 4« by BAKER Drivetrain; fits Knucklehead 1936-1947, Big Twin Flathead 1937-1948, Panhead 1948-1964; cast aluminum / steel, black; with 23 T sprocket, chrome-plated kicker cover; USA; gross weight: 22 kg

6-speed transmission »6 in 4« by BAKER Drivetrain; fits Knucklehead 1936-1947, Big Twin Flathead 1937-1948, Panhead 1948-1964; cast aluminum / steel, polished; with 23 T sprocket, chrome-plated kicker cover; USA; gross weight: 22 kg

6-speed transmission »6 in 4« by BAKER Drivetrain; fits Knucklehead 1936-1947, Big Twin Flathead 1937-1948, Panhead 1948-1964; cast aluminum / steel, bare; with 23 T sprocket, chrome-plated kicker cover; USA; gross weight: 22 kg

6-speed transmission »6 in 4« by BAKER Drivetrain; fits 4-speed Shovelhead 1970-1984; cast aluminum / steel, black; with 23 T sprocket, chrome-plated kicker cover; USA; gross weight: 20 kg

6-speed transmission »6 in 4« by BAKER Drivetrain; fits 4-speed Shovelhead 1970-1984; cast aluminum / steel, bare; with 23 T sprocket, chrome-plated kicker cover; USA; gross weight: 22 kg

Gasket kit by BAKER Drivetrain; for Transmission; for BAKER 4-Speed Transmissions; paper / rubber / steel; gross weight: 105 g