Well I`ve known that from the start, but the masses seem to be blinded by the bling. All the old hydraulics were much better. Pretty sad that for years now the riders in the know have swapped out the parts right away.
I would go back and look at the needle. Pull it out from the slide. Is the retaining clip still holding the needle in position? Sounds like a new needle is needed before you start chasing your tail.
I remember a guy that was riding a demo had a switch. In the excitement of the moment he forgot to turn it on. The little steam explosion was entertaining for the crowd, but not for the rider.
The biggest change was the 2010 frame that did not break in half. Have you had the frame and swing arm replaced? Then the major new frame in 2013. Those are not little changes. Get the super smooth if you like a good low score.
What makes you think a bicycle company would continue making trials bikes as it`s such a niche market! I`ve never heard of a Trials bicycle made by them.
Myself, it is just satisfying to take a bone stock 40 year old bike and clean section after section that modern riders have to stop in. That is what vintage is to me, no price tag involved.
The kill switch depends on what year it is. Post pictures, description, (all purple. red, orange guards, bumble bee yellow)might check the Beta websites on VIN numbers,
I rode mine several years with the springs removed. I ended up putting them back in when our vintage sections become harder. Having the clutch beak loose on a steep incline is no fun. If you normally ride easy sections, the two springs removed works great!