Motorcycle Repair: yamaha radian, change engine oil, overflow tube

Question
hi Mark, i  have a 86 yamaha radian 600 , when i park it at night the number 2 piston fills up with gas , i take out the plugs  turn the motor to clean it out  then it runs fine. any ideas on what is wrong .will gas get in the oil like this  ... 2 question - is the PRI on the tank for cut off?   thanks a lot Andy

Answer
Hi Andy,

Sorry to keep you waiting. I usually reply within a couple of hours.

PRI position bypasses the petcock's vacuum system.
It is for refilling the float bowls on the carburetors after servicing them.

Use ON position for riding. Use RES when you've had alot of fun riding and forgot to add more fun to the fun tank.

The needle valve on #2 carb is sticking and causing gasoline to overfill the float bowl. This is caused by varnishing (gelling) of the gas or by other contamination such as rust particles trapped between the needle valve and its seat. Gas may have also flowed into the airbox and and through the overflow tube to ground. Change engine oil and oil filter before riding.

The carbs will need to be removed, thoroughly cleaned, and synchronized to restore proper performance.

IF you send me an email, I'll return several files on cleaning, tuning, and synchronizing carburetors. My email addy is: mshively1@woh.rr.com

Respectfully,
Mark Shively