[SpudRider]

Originally Posted by Weldangrind

I believe you're right.

Looking at the NC250 engine parts diagram, I can verify I was correct. Part #19 in the following diagram is the automatic decompression assembly.



At low engine rpms this assembly protrudes from the bottom of the camshaft, and contacts the roller rocker of the exhaust valves. It partially opens the exhaust valves on the compression stroke, reducing the compression as the engine attempts to start. At higher rps the centrifugal force overcomes the spring, and the lobe swings inside the camshaft, returning compression to normal.

Here is the part listed at Taobao.

http://item.taobao.com/item.htm?spm=...97&ns=1#detail