Laser R5 oil leaking

[GrumpyCat]

I have a 2006 Laser R5 with about 7700 miles.  After storing it for the winter, I got it ready for riding by draining and refilling the fuel tank, cleaning the carburetor and jets.  It was running well for a few weeks, but then one day I couldn't start it, by electric starter or kick starter.
Removed the air cleaner cover and found oil pooling inside.  Also found oil pooling in the exhaust pipe.  Went to the scooter dealer, who told me that the check valve where the oil line connects to the carburetor was probably faulty, allowing oil to leak into the carburetor.  I bought and installed a new check valve and cleaned the carburetor again, but the engine still won't start and the oil fouling continues as before.  Any suggestions?  There is another line from the oil pump to the intake manifold.  Does this have a check valve also?  If I cannot solve this problem, could I remove the oil tank altogether and pre-mix the oil and fuel myself?  If so, what is the correct ratio of oil to gas?

[harry]

yes both valves can leak . if severe oil can
fill the cylinder ,case and exhaust pipe depending where
 the piston stopped eg; top of the stroke , mid stroke  or bottom
 usually you remove the pipe , drain it and crank the motor
and wipe up the oil that comes out .  on some motors if the plug is
out you can push out  oil there too  but you have to remove shroud
 to clean and if you don't the motor will smoke  like its on fire.

anyway, yes you can go pre mix ...  50/1

oilyhans

[GrumpyCat]

Where is the other check valve located?  Is it at the fitting where the oil line connects to the manifold?  Will I have to drop the engine to get to it?

[harry]

there maybe a inline valve  or at the intake.
just remove the seat bucket and all will be revealed !

 oilyhans

[GrumpyCat]

The check valve appears to be in the line between the oil pump and the manifold.  Blowing into this line toward the manifold end is like blowing into a bottle;  sucking from the other end allows air to pass freely.  Assume this is meant to prevent oil from flowing unless there is a partial vacuum at the manifold.  This appears to be working as designed and doesn't explain the oil leak.  I've decided to remove the oil tank, drain the gas tank and refill it with a gallon of 50:1 mix and see how it runs.  As for other issues, the scooter shop guy told me to start with the air mixture screw backed off 1 1/4 turns from fully seated and adjust in or out for best idle.

[GrumpyCat]

If I empty the oil tank and run the engine on pre-mix instead, would any other modifications be necessary, such as to the jets or fuel filter?

[GrumpyCat]

Emptied oil tank, filled fuel tank with 50:1 mixture, pulled oil feed lines from oil pump and plugged them with little vacuum caps.  Scooter seems to be running OK now with original jets. 
Electric starter doesn't work, but that's a separate problem.

[harry]

i keep all  them vacuum caps from the carbs i install
for just that purpose !
 if you had excess oil from the leaky valve  in the case , that  will clear up
so you might be a bit richer in a few days or 50 miles or so.
keep checking your plug .

lots of people have told me they use amsoil  saber  100:1 ,
   but they mix it 80:1 with good results.
 i use it in my tank ( 1oz  ) just for a bit more protection with the 70cc
cylinder kit . but  i still have the pump working too...

i also  removed  most the pumps on my rental scooters and went premix
due to the amount of time i spent getting 8 scooters ready in the spring
with premix you just fire them up  might need a shot of starting fluid
but they are running in 5 mins . might spend up to 1.5 hrs getting the leaky oil
valve ones running .

oilyhans