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Transmissions Complete

Transmissions Complete

BAKER 4-Speed Footshift Transmissions
BAKER 4-Speed Footshift Transmissions
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.
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BAKER 6 into 4 Transmissions
BAKER 6 into 4 Transmissions
When Harley-Davidson first introduced four-speed transmissions, it was a technical breakthrough. Even though some people question the value of having more gears — “the engine already has enough torque!” — the fact remains that more closely spaced gears allow a combustion engine to operate more consistently within its optimal RPM range than fewer gears with wide ratio-steps. That’s why BAKER has packed not just five, but six gears into a case that fits the old four-speed frames. Riders who gave it a try confirm that performance and acceleration are significantly smoother and stronger with the additional two gears.
Gears one through four are closely spaced, the fifth gear is a direct drive (equivalent to the fourth gear in a four-speed transmission), and with a ratio of 0.86, the sixth gear reduces RPMs by another 500 compared to fifth.
On the left side, the primary cover corresponding to the model year fits (tin or aluminum), while a kicker is flanged on the right side. Not all primary covers, however, are compatible with the five-speed pinion used — please check.
Because the transmission is wider on the right than the old four-speed unit, the original exhaust may get in the way. You need to consider this when planning the conversion, as well as that the shift mechanism and cover are taken from Harley’s five-speed gearboxes. Thus depending on your setup, the oil tank and battery tray may also require modifications.
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,
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Transmission Base Plates
Transmission Base Plates

Repair it again or install a brand new 4-speed gearbox in the Big Twin?

Anyone who doesn't necessarily have a 100% correct restoration of the bike in mind will be happy to answer this question with "a brand new one". Especially as it is not always guaranteed that the old 4-speed gearbox will last for a few more decades despite its new interior. After 30 or 40 years of service, cast aluminum does reach its limits, as the Wrecking Crew found out on the Patagonia trip.

Our selection of complete gearboxes from the manufacturer BAKER covers the most common applications and even offers a version with six gears in a housing that fits into 4-speed frames.

What's the point of six gears?

My Panhead is a high-torque motor, it can cope with four gears! You often hear this almost classic argument. However, anyone who enjoys racing knows that the time lost by more gear changes is more than compensated for by the time saved when the engine does not have to work its way through half the rpm range again after each gear change, but can work continuously in the optimum range with small speed jumps. So: the more gears, the faster on the road ...

Why BAKER gearboxes?

BAKER 4-speed gearboxes are - among many other improvements - optimized in one decisive point compared to classic 4-speed gearboxes. Parts from the 5-speed gearboxes are used at the gearbox output, which is otherwise prone to oil leaks. They have an improved guide for the main shaft and the gearwheel of the fourth gear.

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Have any questions?

Our service team will be glad to help out: Mondays - Thursdays 08:00-17:00 CET, Fridays 08:00-16:00 CET, Phone: +49 / 931 250 61 16, eMail: service@wwag.com