[SpudRider]

Originally Posted by fishman10

Yes , when I saw spuds top end tutorial and saw the decompression device I also wondered if that could be my issue. I too hope they tell me what was wrong with it!

The decompression device in the RX3 camshaft is very similar in design to the decompression device in my Honda CRF250X. When adjusting the valves, it's important to turn the crankshaft far enough to click past the knob which partially opens the exhaust valves. Otherwise, you will not get the valve lash set to the proper gap.



The decompression device has a long arm where it exits from the camshaft (see photo above). Once the engine starts running, centrifugal force on the arm causes the decompression device to rotate, moving the knob out of the slot on the camshaft. However, at speeds lower than 400 rpm, the spring holds the knob in a slot at the bottom of the exhaust cam. This protruding knob presses the exhaust valve rocker, and partially opens the exhaust valves.