Oil Mixer Addition
Oil Mixer Addition
After a little research I
found that the oil mixer device on the PK50 and PK 80 Automatica was
similar to the one on the PK 125 Automatica. Also it seemed that all
the casings were cast the same regardless of whether they had an oil
mixer system or not.
The wheel side of the
crankcase has a small bearing cover on the non-mixer model, but has all
the holes for a mixer device. I found the carb also has the linkage in
place to accept the mixer device.
I removed the cap by removing
the three retaining bolts to expose the end of the crank. It turns out
that the only difference between a non mixer engine and a mixer engine
other than the system itself is that the crank nut is different and
incorporates a drive gear..
Above shows the special nut
that drives the mixer device from the parts manual.
To remove the nut I locked the
crank with a con rod holding tool, and then loosened the nut..
With the nut removed I could
start searching for a mixer device. I found the best place to look was
the German eBay site. Ralf at SIP Scootershop was very helpful and offered to
allow me to use their address for sellers that weren't willing to ship
outside of Germany. Now if I can just find one - more to come soon.
I managed to score an oil
mixer device from a PK 50 Automatica, which looks the same from the
outside, but I am concerned it moves less oil due to the original bike
being a 50cc. Since it will now go on a 125cc I may have to modify it
so it pumps significantly more oil. Looking at the part there is a
throttle arm connected to the carb (green arrow), a drive from the end
of the crank (blue arrow), and a small tunnel where the oil is pumped
out (red arrow). The long tube is the oil intake from the tank.
I have taken apart the whole
engine since the previous shots so the crankcase half is no off the
motor and cleaned up. I found that non-oil metered bikes have no hole
drilled through to the intake area for the oil to mix with the
Only one thing to do! I found
a drill bit the same size as the hole out of the oil pump, figured out
where it needed to be drilled, and then drilled straight through the
A test fit on the bare casing
shows how the mixer integrates with the casing half. I might need to
trim the intake tube depending on what happens inside the small frame
One more modification that
needed to be made to the crankcase half was to srill a larger hole to
allow the linkage from the trottle to operate the throttle arm of the
oil mixer. The arm passes through the space just under the carb intake
shown with an arrow above.