Starter stall: It's that annoying sound emanating from your motorcycle, and you've heard it before -- you hit the starter button and hear arrrrrra. You think to yourself, is my battery going belly-up? Or maybe it's the starter. You let off the button, and you wait a second to try it again; this time the engine rotates slowly at first, then gets up to speed before firing. You let out a sigh of relief and wonder what you can do to eliminate this problem.
Just what causes starter stall? There are different elements that combine to put serious strain on your starting system. Things like getting the engine components moving quickly and, of course, compression.
Something can be done to help alleviate the last one, compression. That's the reason for the noise you hear as your starter stalls. The engine parts start to rotate, but then slow down as the compression begins to build.
Compression is one of the main items contributing to battery and starter failure; and compounding this problem is the proliferation of high compression, big inch engines.
A compression release (they are installed in pairs, one per head) is a small valve which threads into the head from the outside. At the bottom of its threaded mounting port is a 0.125-inch hole that enters the combustion chamber near the spark plug hole.
Inside the release is a valve and seat arrangement similar to the intake and exhaust valves in your engine. An internal spring in the release is calibrated to close the valve after the initial compression stroke of the piston is completed.
With a cost of around 75 bucks for a set (plus machining, gaskets, and assembly), some serious consideration would be in order when you look at the cost of battery and starter replacement.
While installation is pretty straightforward, it will vary slightly from engine to engine. It would be wise to consult your local shop or dealer before deciding to go ahead.