1987 Yamaha PW50 Smokes on Startup: Causes – and Fixes

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Understanding Startup Smoke on the 1987 Yamaha PW50

Seeing smoke from your 1987 Yamaha PW50 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 points to a problem helps you keep your PW50 running strong and reliable.

When Is Startup Smoke Normal?

  • Cold Starts: A small amount of white or bluish smoke is common when starting the PW50, especially after it’s been sitting. This is often due to condensation in the exhaust or a bit of extra oil burning off.
  • After Long Storage: If your Yamaha PW50 has been parked for a while, oil can settle in the crankcase or exhaust. The first startup may burn off this excess, causing temporary smoke.

Common Causes of Excessive Smoke on the 1987 Yamaha PW50

If the smoke is thick, persistent, or has a strong odor, it’s time to investigate further. Here are the most likely causes and how to address them:

  • Premix Ratio Issues
    • The PW50 relies on a precise fuel-to-oil mixture. Too much oil in the premix leads to heavy blue or white smoke on startup and while riding.
    • Fix: Drain the fuel tank and refill with the correct premix ratio as specified for the 1987 Yamaha PW50. Use a measuring cup for accuracy.
  • Oil Pooling in the Crankcase or Exhaust
    • Leaving the bike unused for extended periods can allow oil to seep into the crankcase or exhaust, resulting in a smoky startup.
    • Fix: Run the engine for a few minutes to burn off excess oil. If smoke persists, check for oil leaks or overfilled oil tanks.
  • Worn Crank Seals
    • Damaged or worn crank seals can allow transmission oil to enter the combustion chamber, causing thick, persistent smoke and sometimes a burning oil smell.
    • Fix: Inspect the crank seals for wear or damage. Replacing crank seals is a more involved job but essential for engine health.
  • Cold-Start Enrichment
    • Using the choke or starting the PW50 in cold weather can temporarily enrich the fuel mixture, leading to extra smoke until the engine warms up.
    • Fix: Allow the engine to reach operating temperature. If smoke disappears, this is normal behavior.

How to Diagnose the Source of Smoke

  • Color of Smoke:
    • Blue or White Smoke: Usually oil burning. Check premix ratio and for oil pooling.
    • Thick, Persistent Smoke: May indicate crank seal issues or excessive oil in the system.
  • Smell: A strong, acrid oil smell points to oil burning, while a lighter, sweet smell may be normal condensation.
  • Duration: Smoke that clears up after a minute or two is often harmless. Smoke that continues after warm-up needs attention.

Practical Fixes for the 1987 Yamaha PW50

  • Check and Adjust Premix: Always use the correct oil-to-fuel ratio for your PW50. Too much oil is a common cause of startup smoke.
  • Inspect for Oil Leaks: Look for oil around the crankcase, exhaust, and under the bike. Address any leaks promptly.
  • Replace Worn Seals: If you suspect crank seal failure, plan for a replacement. This will prevent further engine damage and reduce smoke.
  • Run the Engine Regularly: Regular use helps prevent oil from pooling in the engine and exhaust, reducing the chance of smoky startups.

When to Seek Further Help

If you’ve checked the basics and your 1987 Yamaha PW50 still smokes heavily on startup, it may be time for a deeper inspection. Persistent smoke can indicate internal engine wear or seal failure that requires more advanced mechanical attention.

Summary

Startup smoke on the 1987 Yamaha PW50 is often normal, especially after long storage or cold starts. However, if the smoke is excessive or doesn’t clear up, check your premix ratio, inspect for oil pooling, and examine crank seals. Addressing these common issues will keep your Yamaha PW50 running clean and strong for years to come.

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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.