Cannondaleriders

Hi

So my engine started to get trans oil in the engne oil. I torn it down most of the way and still no smokin gun. Any ideas what is mostlikely the cause?

You may have to remove the trans and put some air pressure to the cc and use a little soapy water... thats how I found a crack in the case at that faint v between them. Did your trans or cart plate bolts come loose possibly? This is what caused the one I had because the torque values are a bit too low in the manual.

Ok so I foun that the epoxy is missing from the end of the bore that hold the check ball in the oil pump. I'm thinking that must be how the trans oil is getting in the crank case side...

Thanks Ray

I will check for a crack in the "V" while I have it out. How has life been for you? Been to the dunes lately?

Oil bridge?

Problems at the oil bridge or main oil pump would push sump oil into the gearcase, and not the other way around. And the oil pumpblock may be normal, if it's the earlier style that uses the circlip, piston, and o-ring in the checkball boreways -- you don't want to epoxy over the circlips, since those pumps don't leak anyway, and you may need to service in the future -- they would only leak from a missing or nicked o-ring, from day 1. The later pumps that use the pressed in borecaps would need to have the epoxy intact.
When the motor is running, I have measured actual sump pressure at zero to slight vacuum, as a normal scavenge pump is pushing oil out to the frame as fast as it tends to arrive -- that's enough to draw tranny oil into the sump if there is a crankplate seal issue, a loose or missing bolt somewhere, or a case crack as mentioned. When parked, there can be more oil creep to the right side, if a problem is down low enough and the sump level is lower than the gearcase level.

Hi Dave
Good call. I found chunks of te epoxy from the oil pump block in the drain plug and sure enough the large open one has come out.