Originally Posted by Wentwest
Have you explored the crankcase ventilation system? There's a good bit of information on www.ch250.net
in the tech tips. If the ventilation system is plugged you will get a lot of pressure just from the single piston going up and down, and that pressure has to go somewhere. For some reason people seem to think that ripping off the ventilation system will released massive amounts of undiscovered horsepower, and so they do get vandalized from time to time. And, the engineering Honda used in the design was not great either.
Short answer: Yes, and that is not the problem, but thank you.
I know the captive-ball hiss vent in the stator cover is working properly. The CA model, my motor, has a hose that goes from that nipple to a cylindrical plastic condenser chamber, then over the head and into a filter in the airbox, where the liquids drain into a tube. I know none of these are obstructed, and though the motor runs a little easier when I hold that captive ball in place, with no tube connected, there is still an inordinate amount of exhaust escaping past the cylinder, down into the crankcase. The thing I really don't get is how exhaust gasses could be getting out from the housing around the crank itself, directly below the piston and con-rod. I don't want to pull the flywheel off, as I don't have the right tools to do it correctly...
Originally Posted by Warney
Exhaust plugged up?
Nope. Tested that before I put the whole motor back together. Even filed down the factory welds on the inside of the pipe.