Bloody screw won't stay in place!

There has to be another way to get the screw that holds the gear shift to stay in place on my 690. Less than 300km and the shifter is dangling and I'm swearing why I keep missing gears - and I'm sure its starting to ware away the teeth on the shaft. I have tried everything I can think of: Loctite, Spring wash, both together, I've cleaned it out with  engine cleaner and tried but still it come loose. Any ideas from the other dogs?