Top end and pv questions 04 300

[nmhinton]

Hi guys,
my 04 ec300 quit on me the other day. The first sign was that the top end power went, then it just quit altogether. After checking the carb, I started to dismantle the top end. When removing the pv cover on the right side of the cylinder, I noticed that the screw holding the actuator plate for the pv was almost entirely unthreaded such that the rod had no effect on the valve position. Is this reason enough for the bike not to run?
I'm not too familiar with how it works. Anyway, I took the cyclinder off everything looks decent. I am thinking of doing a new piston/rings. To my knowledge, the bike has never had a top end done, and seems to have been ridden quite a bit. What are my options for kits? Will a caliper measurement tell me if I need to go to a "B" size piston, or do I stick with "A?" Where can I find info on tolerances?
Also, I want to clean up the pv. Is it best to remove the entire assembly, or can I just spray it out with carb cleaner? Thanks for your replies.

[Eric K]

If the power valve is stuck closed, then you would lose top end power. However, the engine should continue to run. Did the enginge stop running at all? If so, you likely have another issue.

A caliper does not have the precision nor the access to accurately measure the cylinder bore. You will need a special bore micrometer. Unless you see significant scoring that you want to hone out, go with the A piston since the larger size pistons are often not readily available.

I disassemble the power valve and clean the carbon off with a wire wheel on a bench grinder. It is fairly straight forward to do.

[nmhinton]

thanks Eric,
the bike did stop running altogether and that is what I'm not understanding. Could the closed valve have flooded it out (since I was trying to open up the throttle?)
One more question...regarding the rod that opens and closes the valve, is there a chance that it will become disconnected on the bottom end and require taking off the right cover to fix? I'm afraid that since my hardware on top came loose, the same might be happening in the bottom end, which would be disastrous. How does it attach down there? thanks

[Eric K]

I would not expect the closed valve to cause it not to run.

I don't recall how the valve actuating rod is secured on the bottom. You can tell by moving the rod if it is still secured on the bottom end.

I would start with basic trouble shooting - check spark, spark plug, fuel, carb, reeds...