2020 Yamaha YZ85 Smokes on Startup: Causes & Fixes

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Understanding Startup Smoke on the 2020 Yamaha YZ85

Seeing smoke from your 2020 Yamaha YZ85 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 YZ85 running strong and reliable.

When Is Startup Smoke Normal?

  • Cold Weather: On chilly mornings, a brief puff of white smoke is often just condensation burning off in the exhaust system.
  • After Long Storage: If your YZ85 has been sitting, a small amount of smoke at startup can result from oil settling in the crankcase or exhaust.
  • Initial Warm-Up: Two-stroke engines like the YZ85 may emit a little blue or white smoke as they reach operating temperature, especially if the engine is cold.

Common Causes of Excessive Smoke on Startup

If the smoke is persistent, thick, or has a strong odor, it’s time to investigate further. Here are the most likely causes specific to the 2020 Yamaha YZ85:

  • Premix Ratio Issues: Using too much two-stroke oil in your fuel mix can cause excessive blue or white smoke. The YZ85 requires a precise premix ratio. Double-check your measurements and mix thoroughly.
  • Oil Pooling in the Crankcase: If the bike has been stored on its side or for an extended period, oil can pool in the crankcase or exhaust, leading to a smoky startup. This usually clears after a short ride.
  • Worn Crank Seals: Failing crank seals can allow transmission oil to seep into the combustion chamber, producing thick, persistent smoke. This is often accompanied by a burnt oil smell and may require seal replacement.
  • Excessive Idling or Low RPM Use: Running the YZ85 at low RPMs for extended periods can cause unburned oil to accumulate in the exhaust, which then burns off as smoke when the engine is revved or started again.

Diagnosing the Type of Smoke

  • White Smoke: Usually condensation, but if it persists, it could indicate coolant entering the combustion chamber (rare on the YZ85, but possible with a blown head gasket).
  • Blue Smoke: Indicates burning two-stroke oil. Check your premix ratio and look for signs of oil pooling or crank seal issues.
  • Thick, Oily Smoke: Suggests excessive oil in the fuel or a mechanical issue allowing oil into the combustion chamber.

Practical Fixes for a Smoking 2020 Yamaha YZ85

  • Check and Adjust Premix Ratio: Always use the recommended oil-to-fuel ratio for your YZ85. Too much oil leads to smoke and carbon buildup.
  • Inspect for Oil Pooling: If the bike has been stored, remove the spark plug and kick the engine over a few times to clear excess oil before starting.
  • Replace Crank Seals: If you notice persistent smoke with a burnt oil smell, inspect the crank seals. Replacing them can resolve oil seepage issues.
  • Run the Engine at Proper RPMs: Avoid excessive idling. Ride the YZ85 at the recommended RPM range to ensure complete combustion and prevent oil buildup in the exhaust.
  • Check for Coolant Leaks: If white smoke persists and the coolant level drops, inspect the head gasket and cooling system for leaks.

When to Take Action

Occasional light smoke at startup is normal for the 2020 Yamaha YZ85, especially in cold weather or after storage. However, if you notice any of the following, it’s time to address the issue:

  • Smoke is thick, persistent, or increases over time
  • There is a strong burnt oil smell
  • Performance drops or the engine runs rough
  • Coolant or oil levels are dropping unexpectedly

Keep Your YZ85 Running Clean

Regular maintenance and attention to your premix ratio are key to minimizing smoke and maximizing the life of your 2020 Yamaha YZ85. If you suspect a mechanical issue, addressing it early prevents further damage and keeps your ride enjoyable. For replacement parts and maintenance essentials, MotoSport.com has you covered.

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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.