I always like to tear down the Engine for inspection ASAP on any toy I buy especially one with a 2 stroke Engine , we all know they run perfect right up until the last millisecond then poofkaboom.

One thing I noticed with the MXZ when I picked it up was it smoked alot, the owner claim it was from fogging it after the snow season, sounds reasonable I did run it long enough to clean out but I also noticed the exhaust had a huge amount of oil dripping out, the exhaust at the exhaust manifold also was leaking and dripping oil into the bottom of the Engine compartment.

Once out I pulled the intake manifold and rotary valve, I noticed a bunch of oil in the pocket where the drive gear is for the oil injection way to much to be considered normal so I filled up the RV drive gear lube hose to see if the RV drive shaft seal was leaking, it turns out it was where the 2 cases meet it was leaking, see the pics.

I will know more when I split the cases, I planned on changing the crank seals so this is not a big deal it was coming apart anyways.

The green arrows are pointing to damage to the cases where metal got between the rotary valve (RV) and the case the red arrows are where the cases meet and the oil is seeping out between the cases.

After 10 minutes the oil puddles up.

RV damage by something hard, assuming metal getting between the RV and the cases.

Same damage spot just the other side of the RV

The casting flaws on this intake setup match up alike a after thought product, they don't match, this will change, the pink arrows are the cases their is a ledge on the sides, you can only remove so much metal on the sides then yo u lose critical support the RV needs to back it up, the factory could have done a better job of designing the intake, I will use epoxy to fill the area between the blue arrows on the manifold to build it up then match them to the cases.

Both sides are the same.

More pics of intake flaws and tunnel problems that need changed, this will really wake up this Engine once the casting and production flaws are removed.

The cylinder on the clutch side had the metal that hit the RV damage the piston and cylinder wall slightly.

No bevel around the ports.

RAVE valve, this is cool, at lower RPM's the valve is lowered effectivally lowering the height of the exhaust port, this means a longer power stroke, more trapped charge so more compression, this makes lots of bottom end torwque, at higher RPM's the valve will raise changing the port timing, mo power at higher RPM's

I made some port molds of one of the cylinders to see how much work they need like most production machines they need dialed in.

More

Some serious deformity or flat spots here.

The matching I will be doing is about the same as I did to the 440 ZOOM ZOOM
http://pilotodyssey.com/PO/viewtopic.php?t=759

Here are some more pics of the factory casting flaws.