Motorcycle Repair: oil, valve clearances, yamaha 650

Question
i have a 77 yamaha 650 special the right side as a tap in motor.  can i put a heavier oil in if so what would be good and how much. i have no manual as of yet, but have orderdone. thank you.

Answer
Hi Bryan,

You may use a heavier oil as long as it's a viscosity recommended by Yamaha.

If a noise is present, why not investigate the source of the noise? Noises may indicate engine problems.

Excessive valve clearances may cause ticking or tapping noises and is unharmful, though clearances should be checked
and adjusted.

Other noises from the top and bottom end can cause engine damages and failures. Noises should be investigated.

Respectfully,
Mark Shively