This is something I've theorized for a couple years, but never had anyone trusting enough.... until now.
Let me start with why this type of STVA fails. These STVAs have a simple brush contact DC motor that simply wears out. With a list price of nearly $400, not a fun failure to experience.
My theory started with a friend's ZX636. I saw his exhaust actuator a few years ago when we swapped the exhaust. Looked kinda like this generation of STVA. So, I started digging into the much hated 2006 and up exhaust actuator on the GSX-R. Damn... they look very similar.
On the right is the 01 STVA. On the left, a 2006 GSX-R exhaust actuator. There are only two differences here. First, the diameter of the rotor and the position of one of the two mounting points on the housing. So, let's dig inside.
Here you can see inside both. Damn... they look identical. What's that on the circuit board? Holy FUCK! It's the same circuit board!
Okay, let's check out the gearing. I'll be damned, they're identical inside!
Okay, so we pull the electric motor out of the exhaust actuator and put it in the STVA. NO! It's even simpler than that. You don't have to pull the rotors, you don't have to pull the circuit board. All you have to do is take the rotor side of the STVA and put it on the drive side of the exhaust actuator. Install and you're done. Some of the clips don't line up on the housing, but since the whole thing is screwed together anyway, just break them off. You'll probably break them off taking it apart anyway.
Want some more good news? Nobody wants the exhaust valve on their newer bike. They remove them, and toss them. I'll bet there's a lot of guys on this board that have one laying around taking up space. This trusting person bought one on ebay for $25. Cheap fix, simple and fast to do.