Blue smoke, good compression. Help appreciated. | GTAMotorcycle.com

Blue smoke, good compression. Help appreciated.

palanski

Member
Hello everyone.

Here's the lowdown on my 1983 Yamaha Virago XV500.

  • At low rpm, front cylinder sputters, little smoke.
  • Rear cylinder fires well and is working fine.
  • At higher rpms, front cylinder fires more readily and gives blue smoke.
  • Front cylinder 160psi, rear is 155psi.
  • Carbs have been taken apart and cleaned thoroughly.
  • Float levels seem to be okay, engine not flooding.
  • Front sparkplug is dark, and has what seems like oily residue on it.
  • Pilot screw is 2 full turns out on both cylinders.
  • Carbs have been synced with a homemade manometer.
  • TCI replaced with known working unit.

I'm about to adjust the valve clearance, but I'm pretty sure that's no longer the issue here, and I'm banging my head against the wall now.

Any guidance would be appreciated!
 
Yup valve seals or oil level too high and burning through vent into airbox
 
+1 for valve guides. Compression test would show good, but oil would drip into cylinder.
 

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