BMW 11261461831 Countershaft K75RT

( Manufacturer Part Number: 11261461831 ), ( Custom Bundle: No ), ( Placement On Vehicle: Front ), ( Type: Countershaft )

Review BMW Oem Countershaft fits 1990

The **BMW 11261461831 1990 K75RT Countershaft** is a meticulously engineered component designed specifically for the legendary BMW M1, a high-performance sports car renowned for its racing pedigree and precision engineering. This countershaft, part of the M1 s legendary 3.5-liter inline-six engine (the S35B30), plays a critical role in the transmission s smooth and efficient operation. Crafted from high-grade steel, it is forged to exacting tolerances to ensure durability under the extreme stresses of high-revving performance driving, where the M1 s 321 horsepower and 269 lb-ft of torque demand flawless mechanical reliability. The countershaft interfaces directly with the mainshaft, facilitating the precise gear ratios that define the M1 s legendary shift quality and top-speed capability, often exceeding 155 mph in its road-going variants. This part is essential for maintaining the M1 s iconic manual transmission s crisp engagement and minimal backlash, which were hallmarks of BMW s racing heritage. Whether restoring a classic M1 to its original glory or upgrading a modified engine for modern performance, this countershaft is a vital replacement for worn or damaged units, ensuring optimal gear meshing and longevity. Its compatibility with the K75RT transmission commonly found in the M1 s later models makes it a sought-after aftermarket solution for enthusiasts seeking to preserve or enhance the M1 s legendary driving dynamics. Proper installation requires alignment with the mainshaft and input shaft, often necessitating a thorough inspection of related components like bearings, synchronizers, and seals to prevent premature wear. For collectors and performance-minded drivers, this countershaft is not just a functional replacement but a nod to BMW s engineering excellence in the 1970s and 1980s.

### **Pros and Cons of Buying a 1990 BMW K75RT with the Specified Countershaft (BMW Part Number 11261461831)**

#### **Pros**

1. **Performance Potential** The K75RT is a high-performance motorcycle with a 750cc air-cooled inline-four engine capable of producing around 75 horsepower and 55 lb-ft of torque. With proper maintenance, it can still deliver strong acceleration and top-end speed, especially if the engine is in good condition.

2. **Classic BMW Reliability (When Well-Maintained)** BMW s air-cooled inline-four engines are known for durability if they have been regularly serviced. The K75RT s engine is robust, and with a fresh countershaft, it may have improved longevity.

3. **Timeless Design** The K75RT is a classic BMW motorcycle with a distinctive, aggressive look that appeals to enthusiasts. Its retro styling makes it a desirable collector s item.

4. **Modification Potential** The K75RT is a popular platform for modifications, including exhaust upgrades, carburetor tuning, and suspension adjustments. A fresh countershaft could help restore performance if the original was worn.

5. **Strong Secondary Market** BMW s classic models, especially the K-series, hold value well in the used market. If maintained properly, this bike could appreciate over time.

6. **Riding Experience** The K75RT offers a sporty, upright riding position with good handling for its time. Its weight (around 450 lbs) makes it stable at speed but requires some skill to maneuver in tight spaces.

7. **Potential for Restoration** If the bike is in rough condition, a fresh countershaft could be part of a larger restoration project, making it a more enjoyable and reliable ride.

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#### **Cons**

1. **Age and Wear** A 1990 motorcycle is nearly 35 years old, meaning it has likely accumulated significant mileage and wear. The countershaft alone won t fix issues like worn bearings, seized pistons, or failing transmission components.

2. **High Maintenance Requirements** BMW air-cooled engines require regular oil changes, valve adjustments, and chain maintenance. Neglect in these areas can lead to costly repairs.

3. **Rarity of Parts** While BMW still produces parts for classic models, some components (especially for older K-series bikes) can be difficult or expensive to source. The countershaft itself may be a common replacement, but other parts (e.g., clutch, timing components) could be harder to find.

4. **Fuel and Emissions Concerns** The K75RT uses carburetions and does not meet modern emissions standards. Fuel quality and additives may be necessary to keep the engine running smoothly.

5. **Weight and Handling** At nearly 450 lbs, the K75RT is heavy for its size, making it less nimble than modern sportbikes. It also has a higher center of gravity, which can affect stability at high speeds.

6. **Potential for Hidden Issues** Even with a new countershaft, other critical components (e.g., crankshaft, camshaft, transmission) may be failing or worn. A thorough inspection by a BMW specialist is essential.

7. **Cost of Ownership** While the initial purchase price may be reasonable, ongoing maintenance, repairs, and potential restoration costs can add up quickly. Insurance and storage may also be more expensive than for a modern bike.

8. **Market Demand Fluctuations** Classic BMWs can be niche, and demand may vary. If you re not a dedicated collector, reselling could be challenging.

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### **Conclusion**

Buying a 1990 BMW K75RT with a new countershaft (11261461831) can be a rewarding experience if you are prepared for the challenges of owning a classic motorcycle. The countershaft replacement is a positive step toward restoring performance and reliability, but it is only one part of a much larger maintenance puzzle.

If you are an enthusiast who enjoys working on bikes, appreciates classic design, and is willing to invest time and money in upkeep, the K75RT can be a fantastic project. However, if you prioritize convenience, modern technology, and lower long-term costs, a newer motorcycle may be a more practical choice.

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### **Recommendation**

1. **Get a Professional Inspection** Before purchasing, have a trusted BMW mechanic perform a full diagnostic, including checking the engine, transmission, suspension, and electrical system. Ensure the countershaft is the only major component needing replacement.

2. **Budget for Restoration** If the bike is in rough shape, factor in costs for additional repairs (e.g., clutch, chain, carburetors, brakes). A fresh countershaft is a good start, but other components may need attention.

3. **Consider a Test Ride** If possible, take the bike for a test ride to assess handling, throttle response, and overall condition. Listen for unusual noises (e.g., rattling, knocking) that could indicate deeper issues.

4. **Purchase from a Reputable Seller** Look for bikes sold by dealers with warranties or private sellers with detailed service records. Avoid "project bikes" unless you re fully committed to the restoration process.

5. **Evaluate Your Goals** If your primary goal is daily riding, a modern bike may be more practical. If you re drawn to the K75RT s heritage and willing to put in the effort, it can be a fantastic ride but with realistic expectations.

6. **Join the Classic BMW Community** Connecting with other K-series owners can provide valuable advice, part recommendations, and even potential trade-ins or upgrades.

**Final Verdict:** If you re passionate about BMW classics, mechanically inclined, and prepared for the challenges, the K75RT with a new countershaft can be a great purchase. If not, consider a more modern or lower-maintenance motorcycle to avoid frustration and expense.

Details:

These parts are removed from once running machines. They may have some repairs or they need. They will not look like new parts. They may have some dents, scratches, cracks and/or missing pieces.

#Dreamlike, Removed From: 1990 BMW K75RT with 56,757 miles. They may not be clean. 1990 Bmw K75rt Oem Countershaft, This countershaft is in good condition and shows normal signs of wear. Removed From: 1990 BMW K75RT with 56,757 miles, Please review all pictures for a visual condition of the item.

Seals may need to be replaced.

part #: 11261461831 prices

• $33.78-$349.69

specifications cyclevintagee:

• for makes: Bmw
• for years: 1990
• mpn: 11261461831
• custom bundle: No
• placement on vehicle: Front
• type: Countershaft

payments cyclevintagee:

• wallet: Google-pay
• other
• credit card: Visa

general cyclevintagee:

• Parts Accessories > Motorcycle Scooter Parts Accessories > Other Motorcycle Scooter Parts Accessories
• condition: Used

shipping cyclevintagee:

• service: USPS Ground Advantage
• carrier: USPS
• transit: 4-10 Days
• class: Standard
• cost: $0.00
• type: Fixed

offer cyclevintagee:

• sold: 0
• availability: In Stock
• options: Ship-to-home
• quantity: 1
• started: April 13, 2026
• best offers: True

returns cyclevintagee:

• policy: Returns Accepted
• paid by: Seller
• time: 30 Days

seller cyclevintagee:

• # reviews: 8
• city: London, Kentucky
• rating: 100.0%

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