2020 Suzuki RM85 Smokes on Startup – Causes and Fixes

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Understanding Startup Smoke on the 2020 Suzuki RM85

Seeing smoke from your 2020 Suzuki RM85 when you first fire it up can be concerning, but it isn’t always a sign of trouble. Knowing when smoke is normal and when it signals a problem helps you keep your RM85 running strong and reliable. This guide breaks down the most common causes of startup smoke and offers practical fixes tailored to your bike.

When Is Smoke Normal?

  • Cold Starts: A small amount of white or bluish smoke is common when starting the RM85, especially on cold mornings. This is often due to condensation burning off or a bit of extra oil in the combustion chamber.
  • After Long Periods of Sitting: If your RM85 has been parked for a while, oil can settle in the crankcase or exhaust, leading to a brief puff of smoke at startup.

In these cases, the smoke should clear up within a minute or two as the engine warms up.

When Smoke Indicates a Problem

If the smoke is excessive, persistent, or accompanied by other symptoms (like fouled spark plugs or loss of power), it’s time to investigate further. Here are the most common causes and fixes for the 2020 Suzuki RM85:

Common Causes of Startup Smoke

  • Premix Ratio Too Rich: The RM85 relies on a precise fuel-to-oil premix. Too much oil in the mix leads to heavy blue or white smoke at startup and during riding. Double-check your premix ratio and adjust to the manufacturer’s recommended specification.
  • Oil Pooling in the Crankcase or Exhaust: If the bike has been stored on its side or not run for a while, oil can accumulate in the crankcase or exhaust. This oil burns off when you start the engine, causing temporary smoke. Running the engine for a few minutes should clear this up.
  • Worn Crankshaft Seals: Damaged or worn crank seals can allow transmission oil to seep into the combustion chamber, resulting in persistent white or blue smoke. This issue often comes with a noticeable drop in transmission oil level. Replacing the crank seals is the only fix for this problem.
  • Excessive Oil in the Air Filter: Over-oiling the air filter can cause oil to be drawn into the engine, leading to smoke on startup. Clean and re-oil the filter sparingly, ensuring excess oil is squeezed out before installation.
  • Incorrect Spark Plug Heat Range: Using a spark plug with the wrong heat range can cause incomplete combustion, resulting in more smoke. Always use the recommended spark plug for your 2020 Suzuki RM85.

Diagnosing the Source of Smoke

  • Color of Smoke:
    • Blue or White Smoke: Usually indicates burning oil, either from premix or a mechanical issue.
    • Black Smoke: Suggests a rich fuel mixture, possibly from a clogged air filter or carburetor issues.
  • Duration: Smoke that disappears after a minute is often harmless. Persistent smoke points to a deeper issue.
  • Other Symptoms: Check for fouled spark plugs, loss of power, or unusual engine noises, which can help pinpoint the cause.

Practical Fixes for the 2020 Suzuki RM85

  • Adjust Your Premix: Use a precise measuring cup and mix fuel and oil according to the RM85’s recommended ratio. Avoid guessing or “eyeballing” the mix.
  • Inspect and Replace Crank Seals: If you notice persistent smoke and dropping transmission oil levels, inspect the crank seals. Replacing them requires splitting the engine cases, so consider your mechanical comfort level before tackling this job.
  • Clean the Air Filter: Wash and dry the air filter thoroughly, then apply a light, even coat of filter oil. Squeeze out any excess before reinstalling.
  • Check the Spark Plug: Remove the spark plug and inspect for oil fouling or incorrect coloration. Replace with the correct type if needed.
  • Run the Engine Regularly: Regular use helps prevent oil pooling and keeps seals lubricated, reducing the chance of smoke on startup.

When to Seek Professional Help

If you’ve checked the basics and your 2020 Suzuki RM85 still smokes excessively on startup, it may be time to consult a professional mechanic. Persistent smoke can indicate internal engine wear or seal failure that requires specialized tools and experience to repair.

Summary

Startup smoke on the 2020 Suzuki RM85 is often normal, especially after cold starts or periods of storage. However, persistent or excessive smoke usually points to issues with premix ratios, crank seals, or air filter maintenance. By understanding the causes and applying these practical fixes, you can keep your RM85 running clean and strong for every ride.

Related Shopping Categories

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Shop Air Filters for a 2020 Suzuki RM85 Dirt Bike.

Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.