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High Torque Bearing Kit

The 34091-85 inner bearing race has been used on Big Twins since 1985. The inner primary bearing rides on this race. By design, this race press-fits onto the transmission mainshaft. This system works fine for stock engines. 100 HP+ engines will make this race walk on the mainshaft. If it walks inboard, it will damage the maindrive gear seal and cause a transmission oil leak. If it walks outboard, it will cause a primary oil leak. Our high torque bearing kit eliminates this condition. Kit includes a precision honed bearing and seal.

 PN 189-56

This part is now included in DD6, OD6, GrudgeBox, and DD7 kits.

  • 1991-2007 Big Twin Models*

* Designed for closed wet primary applications


This part is now included in DD6, OD6, GrudgeBox, and DD7 kits.


Eliminates lateral walking of the mainshaft race, found especially found in high horsepower setups.

This part is now included in DD6 and OD6 kits.

Installation Instructions
Please refer to your Stock Service Manual.


BAKER Drivetrain reserves the right to change prices, terms or policies at any time without notice. Orders can be pre-paid using Visa, MasterCard, American Express, Discover or PayPal. All orders not pre-paid will be sent C.O.D. certified check or money order only unless pre-approved for company check acceptance. Any orders from outside the USA must be pre-paid in US funds via wire transfer; a $30 transfer fee will apply. Prices shown are F.O.B. Haslett, MI.


BAKER™ transmission assemblies and transmission builder 's kits, are guaranteed to the original purchaser to be free of manufacturing defects in materials and workmanship for a period of 5 years from the date of purchase or up to 50,000 miles, whichever occurs first. All other BAKER products are guaranteed to the original purchaser to be free of manufacturing defects in materials and workmanship for a period of 2 years from the date of purchase or up to 24,000 miles, whichever occurs first, except for the following; Warranty does not cover clutch plate wear, throw out bearing failures or mainshaft breakage due to improper clutch nut installation.Electrical components carry a 30-day warranty; cosmetic finishes (chrome plating, hard anodizing, powder coating) are covered for 60 days. Certain promotional products may carry a shorter warranty as specified at the time of purchase. If the product is found by BAKER to be defective, such products will, at the option of BAKER, be replaced or repaired at cost to BAKER.In the event warranty service is required, the original purchaser must call or write BAKER immediately with a description of the problem. If it is deemed necessary for BAKER to make an evaluation to determine whether the transmission assembly or transmission kit or accessory is defective, the entire transmission assembly, whether originally purchased as an assembly or kit, must be properly packaged and returned prepaid to BAKER with a copy of the original purchase invoice. If after evaluation by BAKER a defect in materials and/or workmanship is found, BAKER will, at their option, repair or replace the defective part of the assembly.


Returns are permitted within 90 days of the delivery date. Any merchandise returned for any reason (exchange, credit or modification) must be accompanied by a Return Goods Authorization (RGA) number or it will be refused. Call BAKER to obtain this number prior to returning goods for any reason. There is a 15% re-stocking fee for all returned items. BAKER is not liable for any shipping.


NOTE: Limited warranty does not cover labor or other costs or expenses incidental to the repair and or replacement of BAKER products.This warranty does not apply if one or more of the following situations is judged by BAKER to be relevant: BAKER OEM transmissions ; (these are subject to the OEM manufacturers warranty only), Improper installation , accident, modification (including but not limited to use of unauthorized parts, transmission oils or lubricants), racing, high performance application, mishandling, misapplication, neglect (including but not limited to improper maintenance), or improper repair.BAKER shall not be liable for any consequential or incidental damages arising out of or in connection with a BAKER transmission assembly, transmission kit, component or part. Consequential damages shall include without limitation, loss of use, income or profit, or losses sustained as the result of injury (including death) to any person or loss of or damage to property.BAKER transmissions, transmission kits and accessories are designed exclusively for use in American V-Twin motorcycles. BAKER shall have no warranty or liability obligation if BAKER parts are used in any other application.If it is determined that a BAKER product has been disassembled during the warranty period for any reason, this limited warranty will no longer apply unless you were instructed to do so by a BAKER Drivetrain technician for diagnostic purposes.

High Torque Bearing Kit
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Customer Reviews
4.8 Based on 61 Reviews
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Jerry C.
United States United States

Routine maintenance after 4200 mile trip to Sturgis

This kit is much better than the OEM HD style bearing. Well worth the investment.

Anthony G.
United States United States

High Torque Bearing Kit

So far it has been working perfectly. Hoping for no more failures.

BAKER Drivetrain High Torque Bearing Kit Review
Terry W.
United States United States
  • What model motorcycle do you ride? 2006 Harley Davidson Road Glide

Easy to install , great price, will definitely be buying from Baker again

Dennis C.
United States United States
  • What model motorcycle do you ride? 2008 Thunder Mountain

Inner primary bearing

Bearing was good.Shipping fee awful high.

Matt Z.
United States United States
  • What model motorcycle do you ride? FXR

Bert Baker is a bad mofo

I had the pleasure of personally picking up my 6 speed trans from Baker. I got to meet Burt and tour the shop. Acid rock was jamming, Bert was having a dart. It renewed my faith in humanity.

Web Product ID: 7419343491
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