SKI-DOO 420850245 Exhaust Manifold Gaskets Nos 521CC
fits model: Formula. make: Skidoo, Ski-doo. year: 1987–1988.
( Brand: Ski-doo ), ( Manufacturer Part Number: 420850245 ), ( Part Type: Gasket Exhaust Manifold )
Review SKI DOO Exhaust Manifold Gaskets Oem Nos Plus 521cc fits FORMULA 1987–1988
The **Ski-Doo 420850245 Exhaust Manifold Gaskets** are meticulously engineered replacement components specifically designed to restore optimal performance and sealing integrity to the **1987 1988 Ski-Doo Formula 521cc** snowmobile engines. These gaskets are crafted from high-quality, heat-resistant materials, ensuring they can withstand the intense thermal and mechanical stresses of high-performance snowmobile operation. Engineered to fit precisely within the exhaust manifold assembly, these gaskets eliminate leaks, prevent oil contamination in the exhaust system, and maintain proper compression, which is critical for maximizing power output and fuel efficiency. The gaskets feature a durable, reinforced design that resists warping and degradation over time, even under the demanding conditions of off-piste riding, high-speed cruising, or aggressive racing applications. Whether you're restoring a classic Ski-Doo to factory specifications or performing routine maintenance to extend the life of your engine, these gaskets provide a reliable, long-lasting solution that adheres to OEM standards. Their easy installation thanks to precise cutouts and alignment features makes them an ideal choice for both professional mechanics and DIY enthusiasts looking to maintain peak engine performance in their 521cc Formula models.
Buying the **Ski-Doo 420850245 exhaust manifold gaskets (for 1987-1988 Formula 521cc)** has both advantages and drawbacks, depending on your needs, budget, and priorities. Below is a detailed breakdown of the pros and cons, followed by a conclusion and recommendation.
---
### **Pros of Purchasing These Gaskets**
1. **Direct Compatibility**
The gaskets are specifically designed for the **1987-1988 Ski-Doo Formula 521cc** models, ensuring a proper fit without modification. This reduces the risk of leaks or improper sealing, which can cause performance issues or damage to the exhaust system.
2. **Prevents Exhaust Leaks**
Worn or damaged exhaust manifold gaskets can lead to **exhaust gas leaks**, reducing engine efficiency, increasing emissions, and causing a loss of power. Replacing them ensures a tight seal, maintaining optimal engine function.
3. **Extends Engine Lifespan**
A leaking exhaust manifold can allow **coolant or oil** to mix with exhaust gases, leading to overheating, corrosion, or even catastrophic engine failure. Replacing the gaskets helps prevent such long-term damage.
4. **Improves Performance and Fuel Efficiency**
A properly sealed exhaust system allows for **better airflow and pressure regulation**, which can enhance throttle response and fuel economy. This is particularly noticeable in older Ski-Doo models where wear is common.
5. **Cost-Effective Compared to Engine Replacement**
Replacing gaskets is a **relatively inexpensive fix** (typically under $50 for parts) compared to the cost of repairing or replacing an entire engine due to neglect. This makes it a practical solution for maintaining reliability.
6. **Easy Installation (For DIYers)**
The exhaust manifold gaskets are **relatively straightforward to replace**, especially if you have basic mechanical skills. Most owners can complete the job in **1-2 hours** with standard tools, reducing labor costs if doing it yourself.
7. **Prevents Contamination of Other Components**
Leaking gaskets can allow **exhaust gases to enter the cooling system**, leading to **foamy coolant** and potential damage to the water pump, thermostat, or radiator. Replacement mitigates this risk.
8. **Maintains Emissions Compliance**
If your Ski-Doo is used in areas with **emissions testing**, a leaking exhaust system can cause it to fail inspections. Replacing the gaskets ensures compliance with local regulations.
---
### **Cons of Purchasing These Gaskets**
1. **Potential for Counterfeit or Low-Quality Parts**
Some aftermarket gaskets may be **cheaply made**, leading to premature failure or leaks. While reputable sellers (like OEM suppliers or trusted dealers) minimize this risk, there is still a chance of receiving subpar components if buying from unverified sources.
2. **Additional Labor Costs if Not DIY**
If you **do not have mechanical experience**, hiring a professional to replace the gaskets could add **$50-$150 in labor costs**, increasing the overall expense. However, this is often outweighed by the long-term benefits.
3. **Risk of Overlooking Other Issues**
When removing the exhaust manifold, you may discover **additional problems** (e.g., cracked manifolds, worn gasket surfaces, or exhaust leaks elsewhere). If these are not addressed, the gasket replacement alone may not fully resolve performance issues.
4. **Limited Availability of OEM Parts**
Original equipment manufacturer (OEM) gaskets may be **hard to find** from Ski-Doo dealerships, forcing buyers to rely on aftermarket alternatives. While aftermarket parts are usually fine, some owners prefer genuine components for peace of mind.
5. **Time-Consuming for Inexperienced Owners**
If you are **not familiar with Ski-Doo engine work**, the process could take longer than expected, especially if you encounter resistance when removing bolts or misaligning the manifold.
6. **Potential for Misalignment or Improper Sealing**
If the gaskets are **not installed correctly** (e.g., not centered properly or compressed unevenly), they may fail prematurely or cause leaks. This requires careful attention during installation.
7. **Cost of Replacement Tools (If Needed)**
Some installations may require **specialized tools** (e.g., a torque wrench for proper bolt tightening, a gasket scraper, or a manifold puller). If you don t already own these, there may be an additional upfront cost.
8. **Environmental and Safety Concerns During Removal**
Exhaust manifolds can be **hot** when removed, and coolant may be present, posing a **burn or slip hazard**. Proper safety precautions (gloves, eye protection, and allowing the engine to cool) are necessary.
---
### **Conclusion**
Replacing the **Ski-Doo 420850245 exhaust manifold gaskets** is a **practical and cost-effective maintenance task** for the **1987-1988 Formula 521cc** model. The benefits such as **preventing leaks, improving performance, extending engine life, and avoiding costly repairs** far outweigh the minor drawbacks, which are mostly related to **part quality, installation difficulty, or hidden issues**.
The **biggest risk** is purchasing **low-quality gaskets or failing to address related problems**, but this can be mitigated by **buying from a reputable seller** and **following proper installation procedures**. For most owners, this is a **simple and worthwhile upgrade** that should be done as part of routine maintenance.
---
### **Recommendation**
1. **Buy from a Trusted Source**
Purchase the gaskets from an **authorized Ski-Doo dealer, a well-reviewed online retailer (e.g., Amazon, eBay with positive feedback, or specialty snowmobile parts stores), or a manufacturer like **BorgWarner or Fel-Pro** (known for high-quality gaskets).
2. **Consider OEM vs. Aftermarket**
- **OEM gaskets** (if available) are the best choice for **long-term reliability** but may be harder to find.
- **Aftermarket gaskets** (e.g., **Fel-Pro, Sealed Power, or AC Delco**) are often just as good and may be more affordable.
3. **Prepare for Installation**
- Gather the necessary tools: **socket set, torque wrench, gasket scraper, new gaskets, gasket maker (optional), and a drain pan for coolant**.
- If unsure, **watch a Ski-Doo exhaust manifold replacement tutorial** (e.g., from **YouTube channels like "Snowmobile Repair Guy"**).
- Have **coolant and a funnel** ready in case some spills during removal.
4. **Inspect for Additional Issues**
While replacing the gaskets, **check the exhaust manifold for cracks, the head gasket for leaks, and the bolts for wear**. Replace any damaged components to ensure a complete fix.
5. **Follow Proper Torque Specifications**
Over-tightening or under-tightening bolts can cause **warping or leaks**. Use a **torque wrench** and follow the manufacturer s specifications (typically **25-30 ft-lbs** for Ski-Doo exhaust bolts).
6. **Test After Installation**
After reassembly, **start the engine and check for leaks** (listen for hissing near the manifold). If leaks persist, **recheck the gasket installation or bolt tightness**.
7. **Maintain Regularly**
Since gaskets can degrade over time, **inspect them during routine maintenance** (every **2-3 years or 50-100 hours of use**) and replace them preemptively if signs of wear appear.
---
### **Final Verdict**
**Worth the investment.** The **Ski-Doo 420850245 exhaust manifold gaskets** are a **simple, affordable fix** that prevents **serious engine damage, performance loss, and costly repairs**. With proper installation, they will **extend the life of your Ski-Doo and keep it running smoothly**. If you re comfortable with basic mechanical work, **DIY replacement is the best approach**; otherwise, hiring a professional is a reasonable alternative. **Do not delay replacement if leaks are present**, as the long-term consequences can be severe.
Details:
1987 FORMULA PLUS 521. PART # 420850245 SKI DOO EXHAUST MANIFOLD GASKET. 1988 FORMULA PLUS 521.
part #: 420850245 prices
- $5.00-$13.99
specifications exhaustsnowmobilee:
- for models: Formula
- for makes: Skidoo, Ski-doo
- for years: 1987-1988
- brand: Ski-doo
- mpn: 420850245
- part type: Gasket Exhaust Manifold
offer exhaustsnowmobilee:
- availability: In Stock
- best offers: True
- started: April 9, 2026
- options: Ship-to-home
- sold: 0
- quantity: 2
payments exhaustsnowmobilee:
- credit card: Visa
- wallet: Paypal
- other
returns exhaustsnowmobilee:
- policy: Returns Accepted
- paid by: Seller
- time: 30 Days
general exhaustsnowmobilee:
- condition: New other see details
- Parts Accessories > Snowmobile Parts > Exhaust
shipping exhaustsnowmobilee:
- cost: $0.00
- class: Standard
- type: Calculated
- carrier: USPS, UPS
- transit: 4-7 Days
- service: USPS Ground Advantage, UPS Ground
seller exhaustsnowmobilee:
- city: Sanford, Maine
- rating: 99.7%
- # reviews: 1901
Ski-doo 420850245 Is Similar To:
- 02-147 Kimpex Ski Doo Moto (24.8% similar) Complex replacement part for bro fits many 250 elan TNT, 340 Everest some future spirit model's. Complex ski doo moot exhaust grommet...(September 22nd, 2017)
- 02-222pl-c Bikeman Performance Bmp Ski-doo Powder (17.6% similar) This exhaust can sounds awesome...(December 31st, 2016)
- 02-228-sb Bmp Performance Y-pipe Ski-doo (15.7% similar) All manifolds fit simply replace the stock one for horsepower gains. No jetting for efi controllers required, we just recommend using premium pump fuel. Available for many of the popular arctic cat and ski model's with gains up to 12 horsepower. Id: Sb mfg price: 199. 95 size: great bolt on ...(April 27th, 2017)
- 02-228pl-b Bikeman Performance Bmp Ski-doo (15.5% similar) Simple, are you a die hard arctic cat enthusiast. If your answer is yes, so we and can prove it. If you want a light muffler that barks, powder lite is the way to go. 2-LBS and they fit great with laser cut mounting brackets. Arctic cat ATV dealer of the year. See pictures for examples of the damage...(November 13th, 2017)
- 02-228pl-c 241-01468pc Bmp Ski Doo Powder Lite (18% similar) This application is the bump full velocity stainless steel muffler. See on previous page...(March 7th, 2017)
- 03-211-c Bikeman Performance Bmp Ski-doo (15.7% similar) Please e-mail or call for a rma. Bull item must be in original condition packaging with all tags attached. Arctic cat ATV dealer of the year. Simple, are you a die hard arctic cat enthusiast. If your answer is yes, so we and can prove it...(July 2nd, 2017)
- 03-212 Bikeman Performance Bmp Ski-doo (16% similar) Arctic cat ATV dealer of the year. Bull item must be in original condition packaging with all tags attached. Simple, are you a die hard arctic cat enthusiast. If your answer is yes, so we and can prove it. Bike man performance exhaust manifold - black brand new, in factory packaging bolt on this ...(July 10th, 2017)
- 03-212-c Bikeman Performance Bmp Ski-doo (15.7% similar) Bull item must be in original condition packaging with all tags attached. Bike man performance ceramic y-pipe exhaust manifold - Ski-doo ho SDI e-etc brand new, in the factory packaging bolt on this high flow for instant power gains this rev is one of best manifolds MARKET2-3 peak horsepower not ...(November 24th, 2017)
- 054460 Ski-doo Ski Doo Exhaust Pipe (37.7% similar) Virtually new exhaust pipe. Came out of etc...(December 26th, 2016)
- 08-2301 4630-0067 Kimpex Ski Doo (16.8% similar) Items are for sale locally and we update our listings constantly to prevent unavailability. Free shipping is for us lower 48 states only...(April 4th, 2017)
- 09-895 Starting Line Products Slp Single Pipe Set Ski Doo Xp (13.6% similar) ...(September 27th, 2018)
