Okay, here is where we venture in a couple different directions. Originally I intended to replace the 4 parts previously mentioned, those being the gasket (11482-38B10), Plate (25380-10F00), Stopper Comp (25350-24B00) and Stopper Comp Spring (25355-13E10).

However I found something that I think is the problem and it has nothing to do with the parts being replaced. Here is the diagram of the component parts I'm going to start talking about, namely the Stopper Comp Assembly:

From this point on I am going to call the Stopper Comp the arm and I'm going to call the center Shift Gear Cam the star. I'm from Oklahoma, I like to keep things simple.

By the way, now is a good time to read the disclaimer for this site because I'm about to give a lot of personal opinion here.

The Stopper Comp arm appears to me to have one function in life, and that is to keep the shifting star from rotating on it's own. In other words to hold the bike in gear after you've made a shift. I can see no other purpose that this device can have other than to apply resistance to the cam lobes on the shifting star.

The Stopper Comp arm has a small wheel on the end and this wheel rides up and down the peaks and valley's of the shifting star. The Stopper Comp arm has a spring attached to it, a rather stout spring, that forces the wheel of the Stopper Comp to ride up and down those peaks and valley's. At this point I came to the conclusion that is is most likely why my bike likes to pop out of 4th gear, because the spring is weak allowing the shifting star to turn.

Here is how the peaks and valleys work on the shift cam. When you are in gear and cruising the Stopper Comp arm will be in a valley. It is up to the spring attached to the Stopper Comp arm to make sure that it does not come out of that valley short of you hitting the shifter. I was curious about the 6th lobe and then decided it wasn't used because I could see the trails that the Stopper Comp arm left on the shift cam...there wasn't one on that last lobe (6th gear?). This is probably the same shift cam used on other Suzuki bikes that actually do have a 6th gear.

Continued...